The Quarrying Industry of Missouri
(1904)

By E. R. Buckley, Director and State Geologist, and H. A. Buehler

Missouri Bureau of Geology and Mines Vol. II, 2nd Series, Jefferson City, Missouri,
Tribune Printing Company, State Printers and Binders, 1904.

(Continued)

Paving Blocks.

“Stone used for this purpose should, above all, have a capacity to resist abrasion. It should also wear evenly and not become slippery with age.  The granite and rhyolite which occur in the southeastern part of the State are the only stones which are well adapted to use.  The rhyolite becomes very smooth and slippery and for this reason is less desirable than the granite.  On account of this tendency, the rhyolite blocks are not, at present, being used extensively for paving.  Millions of blocks of both porphyry and granite have been used in St. Louis and it is thought that the Missouri granite is equally as desirable as that obtained elsewhere, and for this reason should be used in preference to that from other states.

“Both the sandstones and limestones in this State are too soft for paving blocks.  The St. Louis limestone has been used to some extent, in St. Louis, for block paving, but it is too soft for this purpose and should be rejected in favor of the granite.”

Crushed Stone.

“The many uses to which crushed stone is put, together with the increasing demand, makes this one of the most important branches of the stone industry in Missouri.  The different uses for crushed stone call for some variation in the properties of the stone.

“The stone used for macadam should first have a capacity to resist abrasion and second that quality by which the particles will be bonded together when rolled.  In crushed stone used for railroad ballast it is not required that either of these qualities be developed to a very high degree.  the stone, however, should be sufficiently strong and durable to withstand alternate freezing and thawing without disintegration.  Stone which it used for concrete should break with a rough surface, in order that the cement may be attached more firmly to the fragments.  Crushed stone which is used in the manufacture of granitoid sidewalks, should have a high capacity to resist abrasion.

“The granite and rhyolite of southeastern Missouri are the best stones in the State for macadam.  When used as a top dressing to limestone macadam, the granite provides an excellent wearing surface which will last indefinitely if properly cared for.

“Most of the dolomites of the Cambro-Ordovician system are too soft to make a desirable road metal.  The chert or flint is better adapted to this purpose, although it lacks the cementing or bonding quality.  The two might be mixed and used together to produce an excellent pavement.

“The Plattin limestone, in southeastern Missouri, is one of the best limestones in the State for road metal.  It is used very extensively for railroad ballast and is an excellent stone for this purpose.

“The Trenton limestone is in most places where quarried too soft to be used as a road metal.  It breaks with a rough surface and is an excellent stone for concrete.  This stone is being used extensively in the construction of the railroad bridge at Thebes, Illinois, being selected in preference to the Plattin limestone on account of its rough surface when crushed.  The Bainbridge and Bailey limestones which outcrop between Cape Girardeau and Ste. Genevieve are among the best limestones in this State for ballast and road metal.

“Most of the Burlington limestone is coarsely crystalline and unsuitable for road metal.  Some of the limestone of the lower Burlington in Greene county and elsewhere is finely crystalline and compact and might be used locally for macadam.  At Sedalia this limestone, together with the Chouteau, has been used in the lower courses of the street movements, the surface consisting of river gravel. This combination has resulted in a very excellent pavement for light teaming.

“The St. Louis limestone has been used very extensively both for concrete and macadam.  In general, it is too soft for macadam, although it constitutes a very desirable stone for concrete.

“The sandstone of the Pennsylvanian system (Upper Carboniferous) is too soft for road metal.  Much of the limestone is fine grained and compact and might be used in the construction of macadam pavements.  However, in the larger cities, this stone should not be used except in the foundation courses.  A macadam pavement should always be surfaced with granite or other stone equally as durable.  At Kansas City, St. Joseph, Jameson, Parkville, Blackwater and Amazonia, the Coal Measure limestone is being crushed for railroad ballast, street paving and concrete.  For more detailed information relative to the quarries in the vicinity of these cities the reader is referred to the preceding pages of this report.*  In the southeastern and southwestern parts of the State, the tailings (chats) from the lead and zinc mills are used very extensively for railroad ballast and paving.  Hundreds of thousands of yards of chat are used annually by the railroads.  In the Joplin-Carthage-Aurora district, the chats consist chiefly of flint with lesser amounts of limestone.  This makes an excellent combination for macadam roads and should be used more extensively throughout the State.  Millions of tons may be obtained in the southeastern and southwestern mining districts, with very little cost above that of transportation.”

(* Please Note:  You will find this information in the Missouri Quarries section of this web site according to the location of the quarries.)

Lime and Cement

River and Harbor Constructions.

“Great quantities of limestone are used annually by the United States government in the construction of the cribs, break waters, etc., along the Mississippi and Missouri rivers.  Stone used for these purposes should be hard and durable and having a capacity to resist erosion by the water.  The best limestone in the State for these purposes occurs along the Mississippi river and is easily accessible.  The United States government now operates a quarry at Little Rock Landing, near Ste. Genevieve, from which 87,416 cubic yards of rip rap was quarried in 1903.

Quicklime.

“During 1903 Missouri produced over 1,000,000 barrels of quicklime, most of which was manufactured out of limestone belonging to the Burlington and Trenton formations.  Both of these limestones are exceptionally pure, containing from 98 to 99 ½ per cent. calcium carbonate.

“The great quantity of quicklime is produced from the Burlington limestone.  All of this lime is white and of excellent quality  The Trenton limestone in the vicinity of St. Louis burns to a dark colored lime, which is very strong, but on account of its color, cannot be used for finishing work.  This same limestone at Cape Girardeau makes a white lime of excellent quality.

“The oölitic beds of the St. Louis limestone at Ste. Genevieve are used in the manufacture of quicklime.

“Many other beds of limestone in the Carboniferous system have been used locally for the manufacture of quicklime, although they contain impurities which render the product inferior.

“The dolomite of the Cambro-Ordovician system is used, locally, in many places for the manufacture of quicklime, which is said to be very strong.  At Jefferson City, two companies are manufacturing quicklime out of this dolomite to supply the local market.

“The subject of quicklime will be discussed in detail in a subsequent report which is now being prepared by this Bureau.

Cement.

“The American manufacturers require limestone containing less than 5 per cent. magnesia for the manufacture of a high grade Portland cement.  The Kimmswick (Trenton), Burlington, Lithographic and certain beds of the St. Louis formation consist of limestone which meets this requirement.  Two extensive cement factories are in operation in this State, one at St. Louis and another at Hannibal.  A third cement factory is being erected at Louisiana.

“This industry will be considered in detail in a subsequent report.”

Filters and Glass Sand.

“The Pacific sandstone of the Cambro-Ordovician system, where essentially free from iron, is admirably adapted to the manufacture of glass.  This sandstone outcrops extensively in the eastern part of the State, being quarried at Crystal City, Pacific, Grays Summit and Klondike.  This sandstone is very friable and easily quarried and prepared for use.  The sand is used for many other proposes besides the manufacture of glass.

“The Newton county Tripoli, which is a very porous, decomposed chert, is used very extensively for the manufacture of filters.  Extensive deposits have been opened and there are now three companies operating in the vicinity of Seneca.  A large part of the produce is used for purposes other than filters.”

Miscellaneous Uses.

“The Lithographic limestone, occurring in the vicinity of Louisiana, has many characteristics of stone used for lithographing.  Small blocks of this stone have been obtained which were well adapted for this purpose.  The stone, however, is not sufficiently uniform in composition and texture to constitute a valuable source of this material.

“The sandstone at Warrensburg has been used in the manufacture of grindstones and whetstones.  It is a very quick cutting stone and when carefully selected appears to be well adapted to this use.  A number of the Carboniferous sandstones might be used for this purpose, although they are somewhat soft and wear rapidly.”

Résumé.

“Missouri is well supplied with excellent stone suitable for most constructional purposes.  The red granite from the southeastern part of the State has a national reputation, while the limestone and sandstone have an extensive market throughout the central and south central parts of the United States.  It costs more to quarry, cut and dress the Missouri limestone, but it is interesting to note that in spite of this fact it is taking precedence over the cheaper stones, which are being so widely advertised throughout the Mississippi valley.  Preference is given to Missouri limestone, simply as a result of its superior quality.

“In this brief chapter, it has been impossible to refer to all the individual quarries from which desirable stone might be obtained.  it has only been intended to indicate, in a general way, the adaptability of the stone belonging to the different formations to different uses.  For a detailed description of individual quarries, or districts, the reader is referred to the preceding chapters of this report.”*

(* Please Note:  You will find this information in the Missouri Quarries section of this web site according to the location of the quarries.)

(Please Note: Chapter XI.  Discussion of the Results of the Laboratory Test will not be presented here.)

Chapter XII.

Conclusion.

“Builders and contractors, as well as the general public, are often unfamiliar with those qualities of a stone which make it suitable for one purpose and unsuitable for another.  An attempt to reduce the cost of a building sometimes leads to the use of inferior stone.  Fashion sometimes calls for a light colored stone and at other times for one having a dark color.  Sometimes an inferior stone looks better when first cut and dressed than one which is more durable.  Past experience indicates that the successful operation of a quarry does not depend so much upon the strength and durability of a stone as upon its color and market price.

“The actual cost of quarrying a stone depends, first, upon the ease with which it can be obtained in blocks of the size and form demanded; second, upon the price of labor; and, third, upon the equipment of the quarry.  The cost of the rough stone delivered will be further controlled by the cost of transportation.  The selling price of the stone, however, is not determined by these factors alone, but also by its color, susceptibility for taking a fine finish, and reputation.

“The ease of quarrying will depend upon the position of the stone in the quarry and the amount of waste to be removed.  If the stone is near the top of the quarry its removal will be much less expensive than if it is some distance below the surface.  The thickness of stripping frequently results in the abandonment of a quarry.  Occasionally, the  stripping may be used in such a manner as to pay for its removal, but often it is so thick as to cause the quarry to be abandoned.  When the stripping can be so used as to pay for its removal the cost of quarrying should not depend at all upon its thickness.  The equipment of the quarry, in the matter of improved machinery usually lessens the cost of quarrying, first, through amore rapid removal of the stone at a minimum cost; second, through less waste; and third, through the better preservation of the stone.  A well equipped quarry represents an increased investment, but this is usually more than compensated for by the lessened cost of the operation and the increased value of the stone.  A large part of the value of a building stone is in the wages paid employees.  A difference of 25 cents or 50 cents per day in wages will affect very markedly the expense of quarrying the stone.

“The cost of transportation depends altogether upon the location of the quarry with respect to the markets.  If the stone has to be hauled by team several miles to the nearest station, the expense will be greater than if the quarry were located on the railroad.  A quarry which is located on two competing railroads usually secures better freight rates than one which has the privilege of only a single railroad.  Where there is only one line the rates are sometimes so high as to exclude the possibility of operating the quarry.  As a rule, however, there is very little unfair discrimination by the railroads in Missouri.  The railroad companies recognize the fact that the development of the quarrying industry contributes very greatly to their own prosperity and that exorbitant rates will eventually react to their injury.  Nevertheless, we are confronted with the fact that the quarry owners in the eastern states have an advantage over the western quarry owners by having relatively lower rates of transportation.  It is possible for the quarry owners in Vermont and Massachusetts to place granite on the St. Louis market at a relatively less expense to the producers than can be the granite producers in the southeastern part of Missouri.  This is, in a measure, due to the low freight rates given eastern producers by the railroads.

“It is stated above that the sale of a stone depended in a measure upon its reputation.  When a stone has had a wide and continuous sale for twenty or twenty-five years, it is said to have gained a ‘reputation.’  Sometimes an inferior stone obtains a reputation through which it commands a better price than one of better quality.

“The price of dressed stone depends very largely upon the inherent qualities of the stone and the cost of labor.  There is a very great difference in the ease with which a stone can be cut and dressed.  A stone does not take all the different dressings with equal facility and of two different stones one may take a bush-hammered finish more readily than the other takes a rock faced finish and vice versa.  There are some excellent building stones which are so difficult to dress that they cannot find a market.  The price of labor affects the cost of dressing and an increase of 25 cents or 50 cents a day in wages may render the production of dressed stone unprofitable.

“In the price of labor, both skilled and unskilled, the eastern quarries have an advantage over those located in Missouri and neighboring states.  This, combined with the low freight rates, makes it possible for the eastern quarries to sell stone in the western market in competition with the local quarries.

“In a new country, quarries are usually opened on a small scale, being worked by hand.  This is well enough where the stone is not intended for shipment, but where it is intended to offer the stone in the open market, improved machinery is necessary.  As the demand for stone in the western and southern states increases and the people attain a better appreciation of the value of the home product, the quarries in Missouri will be better equipped and the price of stone will be correspondingly lowered.

“In Chapter Eleven, there is given a table showing the comparative strength of building stones from Missouri and other states.  These results are very flattering to Missouri stone, showing that the limestone and granite are equal to the very best stone obtained from the eastern quarries.  The varying conditions under which the durability tests have been made in other states, renders a comparison of results rather unsatisfactory.  The conditions under which experiments have been performed to determine the loss in weight occasioned by alternate freezing and thawing, but these data are not important.  Tests to determine the loss in strength resulting from alternate freezing and thawing are vastly more important, although prior to this they have only been determined in the preparation of the report on the ‘Building and Ornamental Stones of Wisconsin.’  

“Many of the large public buildings, as well as hundreds of private residences in this State, have been constructed out of stone shipped from quarries outside of Missouri.  Many of these buildings might have been constructed out of native stone, equal if not superior in quality.  For some reason, people obtain pleasure in anything, in which ‘imported’ materials have been used, and as long as this sentiment prevails, granite will be shipped from Scotland and gray limestone imported from our sister states.  The quarrying industry in this State can be materially aided by inaugurating a sentiment, favoring the use of native stone in all buildings within the State, where the local stone is equally as good and desirable for such purposes.

“A good stone costs more than one of inferior quality.  Contractors, however, frequently expect the best grade of stone from one locality at the same price that an inferior stone can be obtained from another locality.  The appropriation for the construction of public buildings is often too small to permit the use of the best materials.  A contractor is sometimes limited in the selection of stone for private buildings by the amount of money at his disposal.

“Some of the monuments erected in cemeteries will retain their inscriptions for only a few centuries.  However, if they fulfill their purpose, they should withstand injury for many centuries, and irrespective of cost, they should be built out of the most durable stone.  A part of the ornamentation should be sacrificed in a more durable stone purchased.  Marble, which has been used for monuments so extensively in the past, is now sold mainly in the rural districts.  Granite is taking its place, and it now becomes necessary to distinguish between the different kinds of granite, selecting that which is most durable.  The Missouri quarries produce only red granite.  This stone is well adapted for the construction of monuments, where durability is of first importance.

“Everywhere one finds that durability is sacrificed for cheapness.  Cheap material is used in the construction of pretentious buildings, which must be rebuilt in one or perhaps two generations.  The permanent wealth of the country is always lessened by the use of poor materials.  A time is coming when durability must receive more consideration and when temporary structures will only be built in newly developed portions of the country.

“Many of the quarries in Missouri are in a very immature stage of development (circa 1904).  The industry may be said to be in its infancy and we stop to ask how best to promote its development. A large part of the value of the stone is in the labor, which is required to quarry, cut and dress it, making it one of the most important industries for the laboring class.  The people of the State should give the industry a fair share of attention and it should be recognized in a public way.  A sentiment should be inaugurated, favoring the use of native stone in all buildings where the stone is equally as desirable as that which may be imported.  Quarry operators should grade their stone, permitting the use of only the best quality in places where inferior stone may prove disastrous to future trade.  Unnatural competition which results in the sale of inferior stone  for a better grade should never be indulged in; the quarries should be equipped with improved machinery; and finally the people of the State should have a better appreciation of what is meant by good building stone.  They ought to know that an inferior stone will eventually prove more expensive than a durable one, although the purchase price of the latter may be greater.  The people ought not to be satisfied to erect public buildings out of cheap stone, but should demand that which is strong and durable.  Our buildings must become more permanent if our civilization is to be what the optimistically inclined predict of it.  We need permanent structures that are simple and have the beauty and solidity of a permanent civilization.”

Appendix.

Composition and Kinds of Stone - Rock Structures.*

Introduction.

“In the foregoing pages, it has been necessary to use many terms which are probably unfamiliar to the general public.  It is important, however, that one who desires to read this report intelligently, should have an understanding of the terms used herein.  He should know the composition and origin of the different kinds of stone, and know something about the changes which they have undergone since they were formed.  Everything that this chapter contains is found in the elementary text books on geology and mineralogy.  These pages are therefore intended for the general public to whom, as a rule, text books on geology are not accessible.  Following this introduction, the chapter takes the form of a glossary, in which the different kinds of minerals, rocks and rock structures are defined, with relation to one another. The statements made in these pages, as to the abundance, hardness, durability, importance, etc., of minerals or rocks, unless otherwise stated, refer to building stones as a class and not to rocks in general.”

(* Page 331 footnote:  “A large part of this chapter is copied verbatim from the appendix to the report on ‘Building and Ornamental Stones in Wisconsin,’ Bul. No. 4, Wisconsin Geol. & Natural History survey, pp. 431-460, 1898, E. R. Buckley.”)

Minerals.

“Every rock or building stone is, as a rule, composed of several different minerals in a state of aggregation.  In the case of sandstone, limestone or marble, a single kind of mineral may constitute 99 per cent. of the entire rock.  It is possible to separate from a rock any one of the minerals of which it may be composed, and by chemical means determine that this mineral is made up of two or more substances known as elements.  All known matter is composed of seventy-four known elements which are combined in various ways.  The eight most important elements in the order of their abundance are:

“Very few of the seventy-four elements above referred to occur free or uncombined in nature.  They generally occur in combination with one another, forming what are known as minerals.  Many of the elements are very rare, constituting a very insignificant part of the earth’s crust.  More than 95% of the rocks considered in this report, are composed of various combinations of fourteen minerals.

“One mineral is distinguished from another by its physical properties, crystallization and chemical composition.  Minerals are classified mainly on the basis of their chemical composition, and in case it is impossible to identify a mineral by its physical properties or crystallization, it must be analyzed in the laboratory.  The percentage of the different elements of which it is composed, will determine its name.

“Every mineral that separates from a solution or a molten magma, where growth is unobstructed, assumes a definite crystal shape.  All minerals crystallize under one of six well defined systems, which are recognized by the number and relation of the plane surfaces by which they are bounded.  Thus, where it is possible to determine the number of faces on any mineral and their relation to one another, we have a means of determining the mineral itself.  In the case of a mineral which is a rock constituent, the crystal faces are usually wanting, and therefore this means of identification is valueless.  In most sedimentary rocks, the crystal faces of the minerals are usually entirely wanting, and in many of the igneous rocks, they are either very imperfect or entirely absent.  In some of the rocks, the individuals are so small that they can only be distinguished by the aid of microscope.

“It has been ascertained by careful study, that the outward crystal form is an expression of a definite internal structure.  This structure imparts to each mineral certain optical properties by means of which one can, with the aid of a microscope, determine the crystal system to which it belongs and ordinarily the mineral itself.  In the determination of the minerals of which a rock is composed, it is necessary to prepare very thin sections for examination with the microscope.

“To one who is studying the rocks in the field, the physical properties are probably more valuable than either the crystallization or chemical composition.

“The color, luster, hardness, cleavage, and streak, are all valuable aids in the ready determination of minerals.  These properties are all defined in the latter part of this chapter.”

Rocks.

“A rock is ordinarily defined as a mineral aggregate.  It consists of grains or crystals of one or more mineral species, which form a mass through their cohesion or interlocking relations with one another.  Rocks are ordinarily classified on the basis of their origin into igneous, aqueous (sedimentary) and metamorphic.  Although this classification is not entirely satisfactory to the student of geology, it is convenient for the purposes of this volume.  The rocks of commercial importance in Missouri, may be classified as follows:

“This classification includes very few of the many different kinds of rocks which are known to geologists.  These, however, are the common kinds occurring in Missouri.  It must be kept in mind, that each rock type passes by insensible gradations into others of the series to which it belongs.  There are all gradations between the rocks of the rocks of the aqueous or sedimentary series, and between the rocks of the igneous series.  Likewise, there are all gradations between igneous, aqueous and metamorphic rocks.

“As the name implies, an igneous rock is one which has had it origin in the cooling and consolidation of molten magma.  Provided we accept the hypothesis that the earth was at one time a molten mass, which has subsequently cooled, the igneous rocks may be either a result of the downward cooling of the earth’s crust, or as a result of the solidification of molten magma which has been pushed up from below, into or through the already cooled portion.

“These rocks exhibit many differences in mineralogical composition and size and arrangement of the grains, as a result of the varying conditions under which the molten material solidified, combined with differences in the chemical composition of the original magma.  Based upon the chemical and mineralogical compositions and upon the size and arrangement of the individual particles, there have arisen a number of different classifications of igneous rocks.  It would be entirely out of place to describe the many different kinds of rock included in any one of these classifications of igneous rocks.  In the latter part of this chapter there will be found a description of the kinds of rocks used for building and ornamental purpose in Missouri.

“The aqueous or sedimentary rocks have their origin in chemical or organic precipitation and mechanical deposition from water.  Were it possible to trace the minerals composing the sedimentary rocks to their original sources, one would find that they have been in a large part, derived from the igneous rocks.  A hole drilled or dug into the ground anywhere, will eventually pass through the sedimentary rocks and enter those of igneous origin.  Wherever a sedimentary rock may occur today, we may be sure that at an earlier time in the world’s history there was one of igneous origin.

“The sedimentary rocks are worked-over material derived from igneous rocks.  Weathering and erosion have been active for millions of years, breaking down the rocks at the surface of the earth.  The rivers are constantly transporting millions and millions of tons of rock flour from the continents into the oceans.  Millions of tons of rock are also being taken into solution and in this way removed from the continent.  The waves that beat upon the shore, are steadily breaking down the cliffs and transforming them into sand and gravel.  The shore currents, waves and tides, pick up and assort this material, and that which is brought into the ocean by rivers, depositing it over the bed of the ocean near the land.  The coarsest material is dropped nearest the shore, while the finer is carried into deeper water.

“The ocean is inhabited by myriads of animals and plants that are continually extracting calcium carbonate and silica from the water to build their shells and skeletons.  As these creatures die, their remains are added to the accumulations of sediment, and in many places, these are so abundant as to form a large part of the deposit.  Besides calcium carbonate and silica, which are the principal substances used in building the shells of marine animals, the water carries in solution other soluble salts which are often precipitated to the bottom of the ocean, mingling with the mechanical sediments and organic remains.  

“Through these various agencies, four principal kinds of sediments are formed, conglomerate, sandstone, shale and limestone (including dolomite).  These deposits form the sedimentary rocks, and between them, one may find every possible gradation.

“The metamorphic rocks are rocks of both the igneous and sedimentary series, which have been profoundly altered through dynamic and other agencies since they were first formed.  Every igneous and aqueous rock has its equivalent in the metamorphic series.  The most abundant metamorphic rocks are gneisses, which may be either altered igneous are altered aqueous rocks; quartzite, which results from the induration of sandstone; and marble which is the metamorphosed equivalent of limestone.

“The early metamorphic rock used as a building stone in Missouri is marble.  Quartzite occurs in a few localities, but it is not sufficiently abundant or in large enough dimensions to constitute a material for building or ornamental purposes.”

Rock Structures.

“The structures which are recognized in sedimentary and igneous rocks, are either original or secondary in origin.  Original structures in sedimentary rocks are those which have been produced through changing conditions of sedimentation, or alternation of sediments.  Through the alternation of sediments, there is formed a structure which is called stratification.  Originally, the sedimentary rocks possess no actual parting planes, but merely stratification, which is a plane along which the rock has a natural capacity to part most readily.  The degree to which this capacity is developed in a sedimentary rock, will depend upon the kind of sediments and the abruptness of change from one to another.

“The igneous rocks which have been formed deep below the surface of the earth were originally massive and homogeneous and without original parting planes.  Igneous rocks, which have solidified at or near the surface, often have an original flowage structure which resembles in some respects the stratification of the sedimentary rocks.  These have a capacity to part most readily along the flowage. planes.

“All rocks at or near the surface of the earth, exhibit secondary structures.  One ordinarily thinks of the rock envelope at the surface of the earth as being a continuous, unbroken mass of rock.  However, when closely examined, it is found to be composed of a mass of various sized, polygonal blocks, to all appearances perfectly fitted to each other.  These blocks have a wide range in size, being from a few inches to fifty or even several hundred feet in cross section.

“The parting planes by which these blocks are bounded, have been produced during or since the consolidation of the rocks, chiefly as a result of compressive and tensile stresses, either simple or complex.  The commonest and most important of these parting planes are joints which develop in sedimentary, igneous and metamorphic rocks, alike.  The relief from stresses in the earth’s crust generally takes place along planes of weakness.  In the sedimentary rocks, the stratification planes are planes of weakness along which actual parting takes place.  These planes might consistently be called joints, but owing to the parallelism with stratification, they are known as bedding¸ in distinction from those planes that are normal or inclined to the stratification.

“Parting planes may be developed in two or more directions, normal or inclined to bedding.  These fractures are known as joints, although usually spoken of by quarrymen, as vertical or inclined seams.  Joints which are normal or inclined to bedding, usually occur in sets almost at right angles to each other.  They are ordinarily classified as ‘dip’ joints and ‘strike’ joints, depending upon whether they correspond in direction with that of the strike or the dip of the rocks.  In the classification of joints, it would be better to consider them as tension and compression joints, as suggested by VanHise*.  The classification into dip and strike joints, is unsatisfactory, in so much as it fails to provide for the possible cases.  The classification into tension and compression joints, is based upon origin and is therefore thought to be more appropriate.  However, this is not of sufficient importance to warrant a discussion in this place.

(* Page 335 footnote:  Principles of North American pre-Cambrian Geology, by C. R. VanHise: 16th Ann. Rep’t., U. S. Geol. Survey, 1896, pp. 668-672.)

“Quarrymen frequently speak of joints as ‘major’ and ‘minor,’ depending upon the length and depth to which they have been developed.  Major joints are those seams which continue to a considerable depth and for long distances.  Minor joints are those seams which originate and die out within short distances usually within the same quarry.  One frequently finds in the Missouri stone short, tight seams, which are known to the quarrymen as ‘dries’ or ‘incipient joints.’  These have, in some cases, apparently been formed by a torsional movement in the rock.  Sometimes the dries are not over a few inches deep and from 10 to 12 inches long.  Near the surface the rock among the major joints has often been removed by solution forming narrow V shaped trenches, sometimes 40 feet in depth.  These are usually filled with mud and clay and are known to the quarrymen, as mud seams.

“The jointing in the igneous rocks is usually more complex than the sedimentaries.  Bedding always occurs in the sedimentary rocks and the joints are mainly vertical, dipping only a few degrees.  The igneous rocks in Missouri are older than any of the sedimentaries, and have been subjected for a greater length of time to the tensile and compressive stresses, which are active in the crust of the earth.  The joints are partly vertical, but many of them are inclined or even approximately horizontal.  Horizontal or nearly horizontal joints, occur in the igneous rocks, corresponding to the bedding planes in the sedimentaries.  These bedding planes may occur either along the flowage planes of surface lavas, or in the originally structureless deep seated rocks, such as granite.

“Quarrymen are, as a rule, familiar with the advantages and disadvantages of well developed bedding and joint planes.  These parting planes may occur in such a manner as to furnish blocks of a convenient size or they may be so far apart as to be of no assistance in quarrying.  Again they may be so abundant as to break the stone into blocks, which are too small for building or other constructional purposes. In case the stone in a quarry is broken into small blocks by bedding ad jointing planes, it can usually be handled very economically for the manufacture of crushed stone, or in the case of suitable limestone for the manufacture of quicklime.  Where the stone is desired for heavy constructional work, the presence of numerous joints is a source of great annoyance and expense to the quarrymen.  A combination of vertical and inclined joints, even though the latter are relatively few, are often the cause of considerable waste in a quarry.  Vertical joints occurring alone are the most desirable for the profitable exploitation of stone for building purposes.  The ‘dries,’ referred to above, are a source of very great annoyance and occasional considerable amount of waste in some quarries.

“As a rule, the joints occur in pairs which strike near at right angles to each other.  A series of parallel jointing planes are usually spoken of as a set of joints.  It is usual to find two sets of joints striking nearly at right angles to each other.  Frequently, four sets are found, but seldom more than two of these are vertical the others are usually inclined.  Joints are frequently very abundant in one part of a quarry and sparse in another.  Curved joints are common, occurring both in the sedimentary and igneous rocks.

“Other structures known as faulting, folding, cleavage, schistosity and fissility, are produced in rocks.  Where beds are arched or bent so as to resemble the waves of the ocean, they are said to be folded.  Where these folds are very minute, they are called placations.  Where movement has occurred along jointing planes, and the rocks on one side have been moved up or down with respect to the other, the parting plane is known as a fault.

“Cleavage has been defined as a capacity which a rock may possess to split readily into thin laminae or folia.  This structure is somewhat homologous to stratification, but is distinguished from it by being a secondary and not an original structure.  The parting along cleavage planes, is sometimes smooth and at other times wavy.  The former is known as slatiness or slaty cleavage and the latter as schistosity.  Prof. VanHise,* has made a distinction between cleavage and fissility.  He defines cleavage as ‘a capacity present in some rocks to break in certain directions more easily than others.’  Fisility, he defines as ‘a structure in some rocks, by virtue of which they are already separated into parallel laminae in a state of nature.’

(* Page 336 footnote:  Principles of North America Pre-Cambrian Geology, by C. R. VanHise: 16th Ann. Rep’t, U. S. Geol. Survey, 1896, p. 623.)

“In certain igneous rocks there is developed, either originally or secondarily, a differential parting capacity in three directions.  This is exhibited mainly in certain of the rhyolites, in which the large porphyritic individuals have been elongated and flattened in a common direction.  The plane of flattening in the direction of easiest parting and is known as the ‘rift.’  The plane normal to this and extending in the direction of elongation, has been designated the  ‘run.’  The third plane normal to the other two, is known as the ‘head.’  In the granite quarries of Missouri, the plane parallel to the surface or floor of the quarry, is known as the ‘lift.’

“In general it should be noted that the igneous rocks or their metamorphosed equivalents have structures which are in most respects analogous to those in the sedimentary rocks including stratification, bedding, jointing, faulting, folding, schistosity, fissility and cleavage.  It is important that one who is working in a quarry, should be familiar with the above structures, as a knowledge of their manner of occurrence may often assist in the extraction of the stone.”

Glossary.

“Amphibole is an essential constituent of many granites, but more especially of the basic igneous rock.  It is also an abundant constituent of many schists and altered sedimentaries.  The alteration products of amphibole depend upon the species under consideration, but they consist mainly of talc, calcite, chlorite, epidote and quartz.  These minerals, in turn, may be still further decomposed, as in the case of chlorite, which breaks up into ‘a mixture of carbonates, clay, limonite and quartz.’  (Rosenbusch.)  Under ordinary conditions at the surface of the earth, actinolite is a more stable compound than common hornblende.*

(* Page 337 footnote:  It must be understood that all the changes referred to take place very slowly.)

“Bed. - As used in this report, a bed is considered as that portion of an outcrop or face of a quarry which occurs between two bedding planes.

“Bedding. - This is a plane parallel to stratification along which actual parting has taken place.  It is distinguished from stratification in that the latter is simply a plane of weakness along which the rock has a capacity to part.

“Boss. - This term is popularly used to apply to large outcrops of igneous rocks, having an oval or roundish form, as exposed at the surface.

“Calcite. - Calcite is composed of the elements calcium, carbon and oxygen.  It is more accurately known as calcium carbonate (CaCO3).  The hardness is 3.  Calcite is sometimes clear and transparent, but is more often white or cloudy.  It sometimes contains impurities which impart a brown or pink color.  It has a perfect cleavage in three directions, by means of which it breaks into small six-sided pieces, with inclined faces, called rhombohedrons.

“Calcite is often mistaken by the inexperienced for quartz.  The color of the two minerals is almost identical, but if one will bear in mind that the hardness of calcite is 3 and that of quartz 7, there can be little danger of confusion.  Furthermore, calcite has the perfect cleavage, above mentioned, which is not present in quartz.  Calcite is an essential constituent of all limestones and many sandstones.  It is also a constituent of many of the igneous rocks, being an alteration production of other minerals.  The only important alteration product of calcite is gypsum or the sulphate of calcium.  According to Geikie, a sulphate of calcium frequently forms as an outer crust on marble tombstones, due to the action of Sulphuric acid.  It is not known how general this product may be, but it appears very probably that the efflorescence observed on many limestones may be due to the formation of calcium sulphate.

“Chert. - Chert is a variety of quartz and is composed of silicon and oxygen and has the formula SiO2.  Strictly speaking, it is a variety of hornstone which resembles flint, but having a more splintery fracture and being more brittle.  As ordinarily used, chert and flint are synonymous terms.  Chert occurs chiefly in the limestone formations and is probably both original and secondary.  It occurs in irregular layers and nodules, which vary greatly both in shape and size.  Chert is much harder than the associated limestone, being seven in the scale of hardness.  It usually breaks with conchoidal or splintery fracture and has a sharp cutting edge.  It usually has a white, buff, bluish gray or some intermediate color.  It frequently disintegrates, forming a white powder known  locally as ‘chalk,’ ‘silica,’ or ‘tripoli.’

“Chlorite. - This group of minerals, in which is included a number of species, is composed of various combinations and proportions of magnesium, iron, manganese and aluminum, with hydrogen, silicon and oxygen.

“The hardness of the minerals of this group ranges from 2 to 27.  The members of the chlorite group are characterized by their green color, which is common to silicates containing ferrous iron.  In itself, chlorite is generally an alternation product of some other mineral.  It occurs in fibers and folia in many of the old igneous rocks known as ‘greenstone,’ in which case it is generally an alternation product of amphibole, pyroxene, feldspar or mica.  Chlorite alters to a mixture of carbonates, clay, limonite and quartz.

“Clay. - This term is commonly applied to any mass of earth or shale used in the manufacture of clay wares.  It has no well defined chemical or mineralogical composition.  As used in reference to rocks, it applies to the mineral kaolinite to which the reader is referred.”

“Cleavage. - As defined by VanHise, cleavage is ‘a capacity present in some rocks to break in certain directions more easily than others.’  This structure is discussed along with others in the first part of this chapter.

“The capacity which some minerals have to part more readily in certain directions than in others is known as cleavage.  A mineral may possess cleavage in one or several directions.  It may be well developed in one mineral and poorly developed in others.  The presence of cleavage, its perfection, and its relation to the different faces of the crystal often furnish a valuable means of identification.

“Color. - For a discussion of color in rocks, reference should be made to Chapter II of this report where the subject is discussed in full.

“Concretion. - Concretions are roundish nodules which consist of distinct concentric layers, ordinarily clay.  They are usually an aggregation of mineral matter formed around a center.  A rock mass which exhibits a distinct concentric layers is referred to as having a concretionary structure.

“Conglomerate. - Close to the shore line the coarser pebbles and boulders, which have been worn away from the cliffs of the adjacent coast, are laid down.  These pebbles are generally well rounded, and in the spaces between the individuals finer material settles until the whole becomes a compact, solid mass.  This interstitial material is known as the matrix, and is generally either sand or clay.  When such a deposit has been buried underneath many thousands of feet of other sediments, it becomes consolidated and forms a rock called conglomerate.  After many centuries, through elevation and subsequent wasting away of the land, the conglomerate thus formed may emerge again at the surface as a part of the continental land mass.

“Where the pebbles are comparatively uniform in size a conglomerate is sometimes used for building purposes.  But, as a rule, the decided difference in texture and hardness between the different pebbles and between the pebbles and the matrix, is a fatal objection to its use as a building stone.  It sometimes serves as a beautiful stone for inside ornamental work, where it is protected from the destructive action of the weather.  There are no conglomerates in this State of recognized economic value, and we shall therefore pass them without further discussion.

“Diabase. - Diabase is one of the least abundant igneous rocks in Missouri, being found chiefly in dikes in the granite bosses.  It is formed originally within the crust of the earth, and is distinguished from the other members of the family by the texture known as ophitic.  This texture may be either macroscopic or microscopic.  The rock is usually fine to medium grained, and seldom has a porphyritic texture.  It is generally compact and thoroughly homogeneous.  The color of diabase is decidedly somber, being dark green and sometimes almost black.

“Dike. - A dike is a sheet of igneous rock intruded into other rocks along a fissure, usually normal or inclined to the plane of the horizon.  When a sheet of igneous rock is intruded between beds of rock which are horizontal it is called a sill.

“Dolomite. - See under limestone.

“Dries. - This is a term used by quarrymen and refers to short, tight seams in the rocks.  This, along with other structures, is discussed in detail in the first part of this chapter.

“Feldspar. - The feldspar group contains two series of minerals, under both of which are included several special and sub-species.  Certain of the species differ in the elements which enter into their composition, while others merely in the percentage of such elements.  The two series of minerals are known by the name of their most common member, as orthoclase and plagioclase.  Orthoclase is composed of an admixture of potassium, aluminum, silicon and oxygen, which occasionally a small percentage of sodium, (K, Na)2 Al2Si6O16(Hintz).  Plagioclase contains sodium, calcium, aluminum, silicon, and oxygen, with either one of the following or some intermediate formula:  Na2Al2Si6O16.  The two series differ not only in chemical composition, but also in their habit of crystallization.  The former crystallizes in what is known as the monoclinic system, while the latter crystallizes in the triclinic system.

“A few characteristics will suffice to distinguish them from other associated minerals.  The color is generally either pink or white.  The hardness is six in the scale, being surpassed, among the common minerals, only by quartz.  They have two very pronounced cleavages at right angles to each other, in consequence of which they generally have smooth, glistening faces.  Feldspar is not a widespread or abundant a constituent of building stones as quartz.  It is found mainly in the igneous rocks, although it is often a subordinate constituent of sandstone.  It is an essential constituent of granite, gneiss, porphyry, and many of the allied rocks.  In fact, it is seldom absent from any of the igneous rocks.

“Feldspar is a compound which is decomposed and taken into solution with less difficulty than quartz, and is seldom found in the ancient rocks in an entirely unaltered condition.  Its ready cleavage permits of an easier passage of water in and through its entire mass, presenting favorable conditions for slow chemical changes.  The molecules are in some manner slowly broken down, and we (sic) have formed from the feldspar by a rearrangement and recombination of the elements, a variety of different products, among which may be mentioned kaolin, quartz, chlorite, mica, epidote, zoisite and calcite.  Decomposition of the feldspar takes place wherever it is exposed to the action of percolating water or to the weathering action of the atmosphere.  In some manner these alterations, however slowly they act, must eventually effect the strength and durability of the rock of which the feldspar forms a part.

“Fissility. - Fissility has been defined by Prof. VanHise as ‘a structure in some rocks by virtue of which they are already separated into parallel laminae in a state of nature.’  This structure is discussed in detail in the first part of this chapter.

“Flint. - The composition of flint is the same as that of quartz, being SiO2.  It is one of the cryptocrystalline varieties and is closely allied to chalcedony.  It varies in color from grayish blue to brownish black when unaltered.  It breaks with a conchoidal fracture and has a sharp cutting edge.  As commonly used, the term flint is applied to the chert associated with the limestone and dolomite formations in the State.  The terms flint and chert are used interchangeably, although technically they are somewhat different.

“Folding.  - Folding is applied to rocks or strata which have been bent into domes and basins or rolls.  This structure is observed mainly in mountainous regions, and is characteristic of both the altered and unaltered sedimentary rocks.  The rocks of the Ozark plateau are in places gently folded.

“Granite. - Granite is supposed to form deep below the surface of the earth, under peculiar conditions of heat and pressure, whereby the elements of the molten magma are allowed to enter into various combinations, forming minerals having definite characteristics.  The rock thus formed is completely crystalline, and composed of the essential constituents quartz, orthoclase, and one or more minerals from the mica, pyroxene, or amphibole series.  Plagioclase feldspar, magnetite, pyrite, zircon, apatite, and a number of less important microscopic minerals are present as accessory constituents.  The minerals, as a rule, have irregular outlines and interlock in a very intricate manner, each of the individuals having very much the appearance of being irregularly dovetailed into those adjacent.  This interlocking character of the minerals accounts for the fact, that as a rule, an individual can only be separated from the mass of the rock by severing it at some part.  This characteristic of igneous rocks also accounts, in part, for their strength and the difficulty which stone-cutters experience in working them.

“In certain of the granites the essential mineral constituents are very small, being distinguishable only by the aid of a lens.  Such a granite is generally designated as fine grained.  In others the essential constituents are often as much as a quarter or even a half an inch in diameter.  These are spoken of as being either coarse or very coarse grained.  Between the two extremes there are all degrees of coarseness (or fineness).  Frequently a granite is found in which certain of the feldspar individuals are very large and stand out bolding in a fine grained groundmass.  Such a rock is called a porphyritic granite.

“Granites are discriminated from one another by the predominant ferro-magnesian mineral among their constituents, and are known as biotite-granite, muscovite-granite, hornblende-granite, augite-granite, etc.

“The color of granite differs greatly in different localities.  The color depends, not alone upon the color of the individual minerals composing the rock, but also upon the size and distribution of the constituents.  With respect to color, granites may be classified as red and gray.  Whether a granite belongs to the first or second class will depend upon the red or white color of the feldspar.  Many granites contain both red and white feldspar, but so long as the red variety is sufficiently abundant to impart a reddish tint to the rock it is called a red granite.  The most brilliant red granites have a preponderance of medium-sized red feldspar individuals.  As the individuals become finer grained and biotite, amphibole or phyroxene become more abundant, the color is subdued and we have a dull red granite.

“The gray granites are dark or light colored, depending upon the size of the individual minerals and the amount and kind of the ferro-magnesian minerals present.  The lightest colored granite has a preponderance of white feldspar and contains muscovite as the main ferro-magnesian mineral.  The dark gray granites contain less feldspar and a greater abundance of biotite, hornblende, or pyroxene.  Occasionally one finds a granite which has a peculiar iridescent hue, which is due to the presence of one of the plagioclase feldspars, usually labradorite.

“Granite is generally massive, but occasionally one finds a quarry in which the rock splits in one direction much more readily than in others.  This direction is known by the quarrymen as the rift.  When it becomes very pronounced and wavy the granite is known as a gneiss, and should be classified under the metamorphic series.

“Granite is fresh or altered, depending upon the state of preservation of the mineral constituents.  The more common alterations to which the various rock forming minerals are subject are mentioned in connection with the descriptions of the different minerals.  One can readily see that the alteration and decomposition of the individual minerals would, in time, result in the breaking down or crumbling of the rock itself.

“Greenstone. - In the nomenclature of igneous rocks the name ‘greenstone’ has no definite significance, having been applied to almost any rock which has a green color.  The main kinds of greenstone are known as diabase, gabbro, and basalt.  These rocks have, as their main constituents, plagioclase feldspar, amphibole, mica and pyroxene.  All of the three last may or may not be present.  To these essential constituents may be added from ten to twelve accessory minerals, some of which are present in each kind of rock.

“It will be noted that the constituents of the greenstones are among the more readily decomposed and disintegrated minerals.  For this reason, and on account of the dark, somber color of the rock, they are not generally sought after as building stones.

“Hardness. - The hardness of a mineral is relatively constant.  for convenience, all minerals are referred to a scale of hardness of ten units composed of common or well known minerals which are as follows:  (1) talc; (2) gypsum; (3) calcite; (4) fluorite; (5) apatite, (6) orthoclase; (7) quartz; (8) topaz; (9) sapphire; and (10) diamond.  The hardness of any mineral is determined by its ability to scratch the members of this scale.  The degree of hardness is expressed by the number of the mineral in the scale, and minerals of intermediate hardness are expressed by fractions.

“Hematite. - Hematite, or iron sesquioxide, is composed of iron and oxygen, but the proportion of the two elements is different from that in magnetite.  The chemical composition of hematite is Fe2O3.  It has a metallic luster.  The streak is red.  The color is generally steel gray to iron black, but as a rock constituent it often occurs in minute blood-red flakes.  Besides occurring as a rock constituent, it is often discovered in massive beds, forming one of the most valuable iron ores.  It often occurs as a cementing material in sandstone, binding together the individual grains, and with limonite, is generally the cause of the brown and red color of the sedimentary, igneous and metamorphic rocks  Hematite hydrates very slowly to limonite.

“Joints. - Joints are parting planes, by which the rocks near the surface of the earth are separated into polygonal blocks.  This structure is discussed in detail in the first part of this chapter.

“Kaolinite. - Kaolinite is a hydrosilicate having the composition H4Al2Si2O8.  It has a white, grayish white, yellowish, and sometimes brownish or reddish color.  It is usually plastic.

“It occurs in large quantities as a decomposition product of granite and is often more or less mixed with quartz.  It is widely distributed in small quantities through the igneous and sedimentary rocks, being present in grains and scales.  It is usually an alteration product of feldspar and is commonly found associated with the old feldspathic igneous rocks.

“Layer. - This term is applied to a bed or stratum of rock.

“Ledge. - The term ledge is ordinarily applied to several beds of rock occurring in a quarry.  In some instances, however, the term is applied to a single bed.  In this report an attempt has been made to confine its use to an outcrop consisting of two or more beds.

“Lift. - This is the plane approximately parallel to the floor of the quarry, along which the stone is usually split in quarrying.

“Limestone. - In the ocean, beyond where the clay is deposited, calcium carbonate or calcium magnesium carbonate (CaCO3 or (CaMg) CO3) is usually deposited.  This deposit is composed mainly of the shells of marine animals and calcium carbonate resulting from chemical precipitation.  This deposit, is in the case of those previously described, is consolidated and transformed into rock through the pressure of superincumbent deposits and the addition of cementing material from percolating water.  This rock may be brought to the surface as a part of the land area, and is known either as limestone or dolomite, depending upon the percentage of magnesium carbonate in its composition.

“The method of formation of dolomitic limestone has been the subject of a great deal of discussion.  Some authorities attribute it entirely to secondary processes after the limestone is deposited, while others assert that it can only be accounted for by contemporaneous chemical precipitation and the extraction from the water of (CaMg) CO3 by living organisms.  The probability is that both original and secondary processes have contributed to its formation.  In one place chemical precipitation may have been the chief agent, while in another it may have been the result of secondary processes.  In other places both agencies may have been equally operative.

“The chemical composition of pure limestone is calcium carbonate, a combination of the elements calcium, carbon and oxygen.  Among the other constituents may be mentioned magnesium, silica, clay, iron oxide and bitumen, all of which are of common occurrence.  By far the most abundant of these constituents is magnesium in the form of dolomite (CaMg) CO3.

“Owing to the presence of magnesium in large quantities in certain of the limestones, authors have been accustomed to apply the name dolomite to limestone which contains a certain percentage of MgCO3, ranging from 18 per cent. to 40 per cent., depending upon the writer.  The term dolomite has such a varied meaning and has been used so loosely by different authors, that it would avoid confusion if some definite usage for it was established in the nomenclature of rocks.  For scientific, as well as practical purposes, it would be best as far as possible, to distinguish limestone and dolomite as different kinds of rock.  If the rock is essentially pure calcium carbonate, it should be called limestone.  If the rock is essentially calcium-magnesium carbonate, it should be termed a dolomite.  If the dolomite becomes important, but not predominant, the limestone should be known as magnesium limestone.  If the percentage of calcium carbonate is less than that of the calcium-magnesium carbonate the rock should be called a calcareous dolomite.

“There are all gradations between the rocks in which the chemical composition is pure limestone (calcium carbonate), and those in which the chemical composition is pure dolomite.  The stone may be a limestone, a magnesian limestone, a calcareous dolomite, or a dolomite.  Either may be qualified by affixing the name of the most abundant subordinate constituent.  If this subordinate constituent chances to be clay, the rock would be an argillaceous limestone or dolomite; if bitumen, a bituminous limestone or dolomite.  Silica often occurs either as original grains of quartz or as a product of infiltration.  It may be almost equal in importance to that of calcium carbonate and in such case the rock might with equal propriety be called an arenaceous limestone or a calcareous sandstone.  Iron is frequently a subordinate constituent, occurring either as the carbonate, oxide or sulphide present in any considerable quantity the rock is known as a ferruginous limestone.  Iron is a cause of the discoloration of many of the limestones after they are placed in the walls and buildings. Iron oxide, in the ferric form, is not liable to cause discoloration after the stone is placed in the wall.  When iron is present as the carbonate or sulphide, it may, in the case of limestone, not only be a cause of discoloration, but it may also weaken the rock.  The sulphide of iron, as described in this chapter, occurs in the form of pyrite and marcasite.  Hopkins, in his report on the marbles of Arkansas (p. 60) says:  ‘The sulphide of iron is more liable to decomposition when it is in the form of marcasite than in the form of pyrite, and is less destructive in dry places than in moist ones, as in the presence of moisture it not only forms the oxide, known as iron rust, but it at the same time produces sulphurous and sulphuric acids which act on the lime, changing it to sulphate of lime or gypsum.  Often the only effect of iron, if present in very small quantities, is to mellow the stone, producing a yellow tint with age.’

“Clay may occur in the limestone either as thin laminae between the layers, or as segregations or disseminated in fine particles throughout the stone.  An admixture of clay has a tendency to soften the limestone, thereby making it less durable.  If present in thin laminae or in pockets it will soon be noticeable by the greater rapidity with which it weathers.  The surface will wear unevenly and soon become ragged and pitted.

“Bitumen, either as petroleum or carbonaceous matter, is often an accessory constituent and imparts to the rock a black color and a fetid odor.  The injurious effect of bitumen depends largely upon the amount present.  It is objectionable, in any considerable quantity, for buildings, on account of its odor and the discoloration which it occasions. In case the stone contains from twelve to fifteen per cent of bitumen it often becomes valuable as a paving material, being used in the construction of rock asphalt pavements.

“Limonite. - The chemical composition of limonite is the same as that of hematite, with the exception that it contains water in addition to iron and oxygen, (Fe2 O3 + 1- ½ H2O).  It is found in all kinds of rocks - eruptive, sedimentary, and metamorphic.  It results mainly from the decomposition of other minerals rich in iron.  As a staining or coloring agent, it is probably more abundant than red hematite.  It also occurs in large masses, and is a valuable iron ore.

“Luster. - Dana* in his ‘System of Mineralogy’ gives several kinds of luster as follows:  Metallic, the luster of metals; adamantine, the luster of diamonds; vitreous, the luster of broken glass; resinous, the luster of yellow resin; greasy, as that of eleolite; pearly, like pearl; silky, like silk.  These lusters have different degrees of intensity, being either splendent, shining, glistening or glimmering.  When there is a total absence of luster, the mineral is characterized as being dull.

(* Page 343 footnote:  A System of Mineralogy, E. S. Dana, p. XXXIV.)

“Magnetite. - Magnetite is commonly known as magnetic iron ore.  It is composed of iron and oxygen and has the formula:  Fe3O4.  The hardness is 5.5 to 6.5.  

“Magnetite is one of the commonist constituents of the igneous and metamorphic rocks, and is most often present in small grains or crystals scarcely visible to the naked eye.  When present in larger individuals it is easily recognized by its brilliant black luster and the property which it has of being readily attracted by the magnet.  Magnetite is not only widely disseminated in grains, crystals, and irregular patches through the igneous and metamorphic rocks, but it also occurs in large beds, constituting a valuable iron ore.  Magnetite alters slowly to yellowish brown limonite ‘which impregnates the surrounding rock.’

“Marble. - Marble is the metamophosed equivalent of limestone and is of sedimentary origin.  Its composition is the same as that of limestone or dolomite but it is usually compact and thoroughly crystalline.  The color of marble varies widely through all shades of white, yellow, brown and red.  Sometimes it is beautifully variegated.  A crystalline limestone is quarried in the southeastern part of this state, which has all the properties of marble and is so-called by the quarrymen.  Marble is a very useful stone both for building, monumental, and ornamental purposes. It is especially desirable for interior decorations.

“The public are in the habit of confusing marble with granite.  The two are altogether different in composition and origin.  The first is of aqueous and the second of igneous origin.  The first is composed of calcite or dolomite and the second of quartz, feldspar and mica or hornblende.

“Mica. - As in the case of feldspar, there are several varieties of mica differing from one another either in the combination, or in the relative amounts of the elements of which they are composed.  The two most important species are muscovite and biotite.  Muscovite contains various proportion so the elements hydrogen, potassium, aluminum, silicon, and oxygen, while biotite differs mainly in containing, in addition to the above named elements, magnesium and iron.  The hardness of muscovite is 2-2.5, while that of biotite is 2.5-3.  Mica is distinguished from other associated minerals by its easy and close cleavage.  It has the appearance of being composed of very many exceedingly thin, glossy sheets, piled one upon the other.  Each sheet or folio can be scaled off with the blade of a penknife, or often with the fingernail.  Biotite is generally black or very dark brown, owing to the iron in its composition.  Muscovite is ordinarily distinguished from biotite by its white or silvery white color.  The dark color of some rocks is largely due to the abundance of biotite in their composition, while many of the gray granites owe their color partially to the presence of muscovite.

“Biotite is altered very slowly to other compounds by exposure to the atmosphere.  The resulting products of decomposition are iron oxide, quartz, chlorite, and a mixture of the carbonates.  Muscovite, under the same conditions, decomposes more slowly than biotite.  The alteration of biotite takes place along the cleavage planes or between the laminae, which hasten decomposition by furnishing a large working surface to the agents of decomposition.

“Mica is an essential constituent of granite, gneiss, and many other igneous rocks.  It also occurs to a less extent in certain of the sedimentary rocks, of which micaceous sandstone is an example.

“Olivine. - The olivine group is now more correctly known as the chrysolite group.  The different species differ somewhat in composition, being composed of varying proportions of magnesium, calcium, iron, and manganese, in combination with silicon and oxygen.  The hardness ranges from 6 to 7.  The predominant color is what is commonly known as olive green.  The luster is vitreous.  Olivine is a constituent, mainly, of the more basic igneous rocks, such as diabase and gabbro. It alters very extensively to chlorite, talc, and serpentine.

“Onyx. - True onyx is an agate-like stone, consisting of layers of silica of different colors.  This stone is not found in Missouri in commercial deposits.  The so-called Missouri onyx corresponds in composition to the Mexican onyx, which usually has the chemical composition of a limestone.  It is formed in caves in the same manner as stalactites and stalagmites, by the waters that drip through the roof or enter the caves from the sides.  This so-called Mexican onyx is usually banded, frequently consisting of irregular, various colored layers which when polished, form a very beautiful stone for decorative purposes.

“Pyrite. - The chemical composition of pyrite is iron and sulphur (FeS2).  The hardness is 6 to 6.5.  Common iron sulphide or pyrite proper, is recognized by its cubical shape and bright yellow color.  The less common form of iron sulphide, known as marcasite, has a much lighter, almost gray color, and is softer than common pyrite.  The occurrence of iron sulphide in both forms is very wide spread being found alike in eruptive, sedimentary, metamorphic rocks.  Both compounds decompose quite readily, but pyrite proper is less affected by atmospheric conditions than marcasite.  This is due to the fact, that much of the iron in the marcasite exists in the ferrous state, while that in the pyrite is more largely in a ferric condition.*  Under the same conditions, the ferric compounds are much more stable than the ferrous, and hence the greater readiness with which the marcasite decomposes.  The decomposition products of the two minerals so differ to some degree.  The decomposition of pyrite results, as a rule, in the formation of limonite and free sulphur, while that of marcasite results in the formation of ferrous sulphate, although, when under water, limonite is also largely formed.”

(* Page 344 footnote:  Mr. A. P. Brown, Proc. Amer. Phil. Soc., Vol. XXXIII, 1894, p. 225.)

“Pyroxene. - The composition of the mineral species included under the general name of pyroxene is nearly the same as that of the species included under the amphibole group.  The individuals of this group are ordinarily composed of two or more of the elements magnesium, calcium, iron, manganese, sodium, and lithium, in combination with silicon and oxygen, with the addition in certain of the important species, of aluminum, as an essential constituent.  The hardness varies from 5 to 6, but in some of the less common species reaches as high as 7.  The color and luster of the cleavage faces are essentially the same as in the preceding amphibole group.  As has been previously observed, it is difficult to distinguish the members of this group from those of the amphibole.  The only ready means is through a determination of the cleavage angles, or a knowledge of the crystal forms.  The most important rock forming member of this group is augite, which name is often used synonymously with pyroxene.

‘Pyroxene is mainly a constituent of igneous rocks, being an important constituent of many of the granites, gneisses, and especially the more basic rocks.

“Through the weathering process pyroxene is slowly decomposed, altering into chlorite, calcite, and epidote.  Under given conditions pyroxene weathers somewhat more rapidly than amphibole, and for this reason is considered a less stable compound.

“Quartz.- The chemical composition of quartz is silicon dioxide (Si O2) which is a combination of the two most abundant known elements, silicon and oxygen.  It is one of the hardest of the common minerals, being seven in the scale of hardness.  It will readily scratch glass and most of the other common minerals.  It possesses no ready cleavage, having as a rule a conchoidal fracture.  As a rock making constituent, quartz is generally colorless, but when found alone it is frequently brown, yellow, purple, milky white, or pink.  When occurring alone or in crystal aggregates, the quartz individuals often have very perfect crystal faces, but as a rock making constituent the individuals generally have round, oval, or irregular outlines.

“Quartz is one of the most abundant minerals.  The glistening sand which forms the bars in many of the larger rivers is mainly quartz.  The white and yellow particles which are caught up by the wind and eddied here and there in small dunes over some of our farms, are mainly quartz.  This loose sand is largely a result of the decomposition of sandstone, which is composed mainly of quartz.  Quartzite, as the name implies, is composed essentially of quartz.  Among the igneous rocks, such as granite, rhyolite, and gneiss, quartz is a prominent constituent.  Rocks which do not contain more or less quartz are the exception rather than the rule.

“Among all the common rock-forming minerals, quartz is the most permanent.  It is very hard and resists, to a high degree, any attempt to break or crush it.  As a result of weathering it is often broken into smaller particles, but it is decomposed and taken into solution only with difficulty.

“Rift. - This structure has been defined in the discussion of rock structures, in the first part of this chapter, as the plane of flattening, or the direction of easiest parting developed in certain igneous rocks.

“Rhyolite. - The rocks which have been placed under this subdivision have essentially the same chemical composition as granite.  They differ mainly in texture and mineralogical composition, occasioned by the entirely different conditions under which they have been formed.  In contra-distinction to the granites, which are formed deep below the surface, these rocks are formed at or near the surface of the earth.

“Porphyritic rhyolite, commonly known as porphyry, is the only variety of this kind of rock which we have occasion to consider.  In this rock, quartz and feldspar are the first minerals to crystallize out from the magma, and make up the porphyritic constituents in the rock.  Sometimes feldspar alone is present, and again both quartz and feldspar are found among the porphyritic individuals.  The remainder of the magma is supposed to have cooled so rapidly as to permit of only partial crystallization.  The rock, as a rule, has a dark, dense background through which are disseminated numerous large, lustrous crystals of feldspar or quartz, or frequently both.  These porphyritic constituents of rhyolite generally differ from those of granite in having well defined crystal outlines.  The matrix of porphyritic rhyolite, as it now occurs, is often composed of a dense mass of microscopic crystals of quartz and feldspar.  In other instances the matrix may be entirely or in part amorphous.

“Run. - This structure has been defined as the plane, normal to the rift, extending in the direction of the elongation of the porphyritic crystals occurring in rhyolite and other igneous rocks.

“Sandstone. - The deposit which is found on the bottom of the ocean beyond the conglomerate belt and in deeper water is composed of small particles of sand.  When this is deeply buried beneath later sediments and the interstices become filled or partly filled with materials deposited from percolating waters, it is transformed into a rock known as sandstone.

“The sandstone vary considerably in composition, but in all cases the preponderant original constituent is round to subangular grains of quartz.  Feldspar or calcite may constitute a considerable portion of the rock, in which case it is called either a feldspathic or calcareous sandstone.  Clay may be so intermingled with the quartz grains as to give the rock the name argillaceous sandstone.  Mica may also be abundant, and the rock is then called a micaceous sandstone.

“The original grains which compose the rock generally have roundish outlines, owing to their having been water worn.  The individuals, therefore, do not interlock as in the case of the igneous rocks.  When first deposited small spaces exist between the grains, but due to consolidation from superincumbent pressure, these spaces may be reduced in size, and through cementation they are either partly or wholly filled by material from extraneous sources.

“The kind of cementing material which binds together the grains will depend chiefly upon the mineral matter carried in solution by the water which has percolated through the rocks, although the mineral particles composing the rock may contribute to the force which brings about a precipitation of the cementing material.  The more important cementing materials are calcium carbonate, iron oxide, and silica.

“It is evident that the hardness of a rock depends upon the state of aggregation, as well as upon the hardness of the individuals composing the rock.  The hardness of quartz is 7, but this is not the hardness of a rock composed entirely of quartz.  The hardness of a rock depends chiefly upon the cementing material and the manner in which the grains are united.  The efficiency of the cement will depend not only upon its inherent characteristics, but also upon the affinity which exists between the grains and the cement.  The hardest and most durable cement is silica.  A sandstone in which the individuals are completely cemented with silica is one of the hardest and most durable rocks.  Sandstone in which the cementing material is calcium carbonate is softer and less durable than the former.  Calcite is one of the softest of the important minerals of building stone, and breaks very readily into small pieces, due to its cleavage.  It is also quite readily dissolved in carbonated waters.  A sandstone in which the individuals are cemented with iron oxide is usually less strong than one cemented with either silica or calcite.  As a rule, iron oxide is the least important of the three cements.

“Any estimate of strength or durability of a rock should take into consideration the conditions of cementation.  In comparing the hardness and durability of sandstone, the relative amount of cementing material, the size of the grains, and the completeness with which the cement has filled the interstices, as well as the kind of cement and mineral constituents, should be taken into consideration.

“Alterations of sandstone are mainly the result of additions or subtractions of mineral matter, usually silica.  Quartzite, as has been previously stated, does not decompose readily although small amounts may be taken into solution and carried away by percolating water.  The cementing materials and the subordinates constituents, such as feldspar, mica, calcite, and iron oxide (or sulphide), are alone subject to alteration in the dense of decomposition.  Feldspar and mica break down into their various alteration products, and calcite is often dissolved and reprecipitated as the sulphate.  Ordinarily iron oxide, in the form of hematite, is reasonably stable, in the form of the carbonate or sulphide, it is readily decomposed, and becomes a source of discoloration.

“Schistosity. - This structure has been defined as wavy cleavage planes in rocks.  It has been discussed in detail in the first part of this chapter.

“Shale. - In deeper water but mainly in the shallow parts of the ocean, beyond the sandstone belt, still finer sediments are deposited in the form of clay.  These deposits, after passing through the ordinary process of consolidation, are transformed into a rock, which is known as shale.  When metamorphosed they pass into slate.  These rocks are not among the important building stones of Missouri and will not be further considered.

“Shaly. - This is a term which is applied to thinly bedded rocks in which the layers are separated by thin leaves of shale.

“Shelly. - This term is used synonymously with shaly.

“Stratification. - The planes along which a sedimentary rock has a natural capacity to part most readily, are known as stratification planes.

“Stratum. - A stratum is commonly known as a layer of rock between two stratification planes. Popularly, the term stratum is used synonymously with bed and layer, although it is thought that its use should be confined to a layer of rock between stratification planes.

“Streak. - The streak is the color of the mineral when powdered, and in the case of the softer minerals is obtained by scratching a piece of porcelain with the mineral which is to be identified.  As a means of determining the minerals of the building stones, this quality is not important except perhaps in two or three cases.

“Stylolite. - This term is applied to the irregular toothed jointing planes occurring in limestone and dolomite.  This structure is illustrated in Plate XXVIII.*

(*  Please note that Plate XXVIII will not be included in this document.)

“Suture Joint. - This term is used synonymously with stylolite.

“Syenite. - This is an igneous rock very closely allied to granite, and usually known commercially, as granite.  It consists chiefly of orthoclase feldspar and one or more of the ferro-magnesian minerals biotite, amphibole, and pyroxene.  Among the accessory minerals are zircon, magnetite, hematite, apatite, eleolite, analcite, etc.  It differs from granite chiefly in the absence of quartz.

“Talc. - Talc is composed of hydrogen, oxygen, iron, magnesium, aluminum, and silica, united in different proportions.  It is usually foliated, but frequently massive or fibrous.  Talc has a peculiar greasy feel which furnishes, as a rule, a ready means of distinguishing it from associated minerals.  The color varies from apple green to white or silvery white.  The luster is often pearly on cleavage faces.  Talc is widely disseminated through the igneous and metamorphic rocks.”