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PLEASE NOTE:  Two portions of this book will not be included at this time:   the scientific discussion of granite and the list of individual granite quarries in Maine.  Eventually, these two sections will be added.  The entire table of contents and list of illustrations are included here, but only the entries with links are actually a part of this document.  At this time not all of the photographs and maps will be presented here, although the photographs and maps have been placed in the "Quarries & Quarry Links, Photographs and Articles" section of the Maine state section according to the location of the quarry.  If you have questions about any portion of the book not presented here, please contact me. Peggy B. Perazzo

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Plate I - Map showing the distribution of granite and related rocks in Maine.
(725 K File)

Areally, granite is perhaps the most important rock in Maine.  Slates, schists, sandstones, and limestones of various types occur in the different sections of the State, but the mountains and hills of the interior and the islands and headlands of the coast for the most part all exhibit slopes and cliffs of massive granite.  Even where the exposures are of other rock varieties the notable abundance of granite dikes and quartz veins indicates the presence of granite at no great distance.  Not only is this rock most conspicuous, but its importance in both the geology and the industry of the State can hardly be overestimated.

The areal distribution of the granite is somewhat irregular, as may be noted on the map accompanying this report (Pl. I).  Three general granitic regions may be distinguished for convenience of description-that of the western tier of counties, that of the eastern part of the State, and the Mount Katahdin area, the north-central portion of the State.  In addition to these larger districts there should also be mentioned three small areas in Lincoln, Kennebec, and the Somerset counties, which are intermediate in position between the three main regions.

The granitic areas of the western group are not widely separated, and the largest of these areas as outlined on the map is not all granite, although, as will be explained in a later paragraph, the intrusive granite forms the larger part of the rock exposed within these limits.

The northernmost of these granite masses is exposed in the elevated country which forms the divide between the Chaudiere drainage on the Canadian side of the international boundary and the headwaters of Androscoggin and Dead rivers in the northern part of Franklin County.  South of this is a much larger area of granite, extending from the western part of Somerset County across Franklin into Oxford County and including prominent peaks, like Mount Bigelow and Saddleback Mountain, as well as the rugged country south of the Rangeley Lakes.

South of this is a large, irregular-shaped area of metamorphic rocks-gneisses and schists-more or less thoroughly impregnated with granite, which extends southward and eastward through seven counties, reaching the coast at Casco Bay on the west and Penobscot Bay on the east.  Southwest of this area is a mass of granite, which constitutes the eastern extension of the White Mountain massif of New Hampshire and reaches the coast at Casco Bay, Cape Porpoise, and York Cliffs.

The Mount Katahdin granite lies wholly within the forested region of northern Maine, and therefore its exact boundaries are unknown.  At the northeastern end of the area is the highest elevation in the State, Katahdin, 5,268 feet above the sea, a typical granite mountain.  To the southwest, possibly connected with this area, is the granite near Lake Onawa, where the rock is well exposed in a deep cut of the Canadian Pacific Railroad.

In the eastern counties three extensive granitic areas may be distinguished.  Of these the northernmost extends southwestward from New Brunswick across the northern portions of Washington and Hancock counties into Penobscot, and almost wholly is forested country.  Southeast of this is the horseshoe-shaped granitic area of Hancock County, which crosses into Washington County near Cherryfield.  On the west the outlying Mount Waldo mass may represent an extension of the same granite, although connecting exposures along the Penobscot River below Bucksport have not yet been observed.  In the Hancock County area the granite can be traced from the shore of Eggemoggin Reach northward along a line of prominent hills, which are best seen from the Maine Central Railroad near Green Lake.  North of Aurora these granite hills have less relief, but east of that place the belt extends southward with increasing ruggedness of topography, Tunk Mountain, near the Washington County Railroad, being characteristic of this southern portion. 

The other occurrence of granite in eastern Maine is the belt extending from New Brunswick across the St. Croix, then southwestward to the coast at Addison, and thence along the coast to Penobscot Bay.  Within this belt are included several large islands-Swans, Deer, and Vinalhaven-and the mountains of Mount Desert owe their topographic prominence to the massive character of the granite composing them.

Of the smaller areas of granite not included within the three groups described above, that in Lincoln County comprises the town of Waldoboro and islands at the head of Muscongus Bay.  The Hallowell-Augusta area in Kennebec, the North Jay and Phillips area in Franklin, and the Hartland and Horridgewock areas in Somerset County represent the larger of many small intrusive masses of granite in central Maine.  With these should be mentioned the granite occurrence in Aroostook County, about 12 miles west of Houlton.

In the preparation of the map (Pl. I), showing the distribution of the granite, as described above, the data used have been largely the results of areal mapping, for folio publication, by E. S. Bastin, C. W. Brown, and the writer, and of general reconnaissance by the writer, assisted by Mr. Bastin.  In the more northern areas the work by H. E. Gregory and the earlier mapping by C. T. Jackson and C. H. Hitchcock have been utilized to supplement this recent work.  Mr. Brown also contributed the results of recent observations in the vicinity of Mount Katahdin.

Geologic Relations.

Wherever the granites of Maine have been studied in any degree of detail, their relations are plainly those of intrusion into part, at least, of the adjacent formations.  Evidence that the granite is the younger rock is found in the tendency shown by some of the granite areas (see Pl. I) toward elongation in a northeast-southwest direction, parallel to the general trend of the main structural features of the region, but more conclusive evidence is found in the fact that the granite actually cuts across the bedding of the sedimentary rocks and has in some localities produced in them a very considerable amount of alteration.  Bordering the granite in Franklin County, for example, and in some other parts of the State, are andalusite schists which plainly represent sedimentary strata metamorphosed by the granite.  In many regions, as will be described later, the granite masses are bordered by gneisses which are formed by a lit-par-lit injection of sedimentary schists by granitic material.  Thus the general relations throughout the State point to the granites being relatively younger rocks.

The feature which is perhaps the most significant in the geologic relations of the granites to the other rocks of the State is the great contrast between the sharpness of certain granite borders and the indefinite character of others.  In the vicinity of Bluehill and Brooksville, for example, in Hancock County, the contact is absolutely sharp, pure granite being succeeded within a foot by schists unmixed with granite.  Along such sharp borders, too, the granite usually preserves its normal texture up to the very contact, and the surrounding rocks show almost no effects of contact metamorphism.  In striking contrast to this are the broad contact zones which characterize most of the granite masses lying farther westward.  In the Rockland region, for example, the Sprucehead-Clark Island granite area is bordered on the northwest by a zone, 3 to 4 miles in width, in which sedimentary slates and schists are intimately associated with injection gneisses, basic granites, fine-grained granite, pegmatite, diorite, gabbro, and diabase.  These igneous rocks were plainly derived from the granitic magma and are most abundant in those portions of the contact zone which lie nearest to the areas of pure granite.  A granite area near South Penobscot, in Hancock County, is almost completely surrounded by a border zone, from one-fourth mile to 1 1/2 miles in width, in which the rocks are largely diorite and gabbro with small amounts of igneous gneiss and fine-grained granite.

Some hint as to the cause of this contrast in the character of granite borders in different regions is obtained from a study of the rocks in the southwestern part of the State, especially in Sagadahoe, Cumberland, and Oxford counties and the southern part of Kennebec County.  Here, as indicated on the map (Pl. I), there are considerable areas from which large continuous masses of normal granite are absent, but in which the prevailing sedimentary schists have been intruded in the most intimate manner by dikelike or irregular masses of pegmatite and fine-grained granite, and in many places have been given a gneissic texture by the lit-par-lit injection of granitic material.  The intruded and injected areas pass gradually into the larger areas of nearly pure normal-textured granite shown on the map.  To explain such intimate injection and intrusion in areas far removed from any outcropping masses of pure normal granite it seems necessary to assume that a granite mass underlies these rocks at no great distance below the present surface and that such injected areas constitute in reality portions of the "roof" of great granite batholiths.

It seems almost certain that the escape of gasses and water vapor and the differentiation of basic rocks from the granitic magma would proceed much more rapidly from the upper surface of a buried magma than from its sides.  It is to be expected, therefore, that portions of the "roof" of such granite masses should be particularly characterized by the abundance of pegmatites, diorite, gabbro, etc., and by notable contact metamorphism of the sedimentary rocks through which these forced their way.  The sharpness of other granite contacts is readily explained by supposing that they represent the side contacts of the granite batholiths, where the gases and water vapors escaped from the magma laterally in much less volume and where the accompanying metamorphic effects were very much less than at the upper surface.

The geologic history of the great granite intrusions of Maine may be summarized, therefore, as follows:

All of the granite masses now exposed solidified below the surface as it existed at the time they were intruded.  The depth at which they solidified varied in different places.  Erosion gradually removed the rocks covering some of the masses and has in some places even revealed their deeper portions, so as to show the sharp lateral contacts.  In other places all or a part of the "roof" of the granite masses still remains.  The present land surface, therefore, truncates the various granite batholith at different horizons.  It is highly probable that a further erosion of 500 to 1,000 feet would expose much larger areas of granite than now appear.

All of the granites of Maine are believed to belong to the same great period of igneous activity.  This conclusion is based on (1) their general lithologic similarity, the differences between granites of different areas being no greater than those observed between different parts of a single area; (2) the nearly continuous extension of certain granite belts for long distances, notably the belt which extends with slight interruptions from New Brunswick to Jonesport and thence to Mount Desert, Deer Isle, Vinalhaven, and Tenants Harbor; (3) the fact that certain areas of granite are connected by belts that are intensely intruded with granitic rocks, thus suggesting that the granite areas may be continuous beneath the present surface; (4) the fact that most of the granites of the other New England States appear to be of about the same age as those of Maine, thus suggesting a single period of great igneous intrusion throughout the whole New England province.

There can be little doubt at least of the contemporaneity of the granite of the Perry basin, on the eastern border of Maine, with that of Vinalhaven, since the granite forms a practically continuous belt between these two localities, and relations are shown in these two regions which approximately fix the age of the granite.  In the Silurian rocks of the Perry region no granite pebbles are found, but such pebbles, plainly derived from the main granite masses of this region, occur abundantly in the conglomerate at the base of the Perry formation, which is of late Devonian age.  The granite of the Perry region is therefore late Silurian or Devonian in age.  Evidence confirmatory, but less complete, is found in the Vinalhaven region, where the granites intrude surface volcanics of Niagaran age.

Scope of This Report.

This investigation was undertaken at the request of the Maine State Survey Commission, which cooperated with the United States Geological Survey in meeting the expenses of the field work.  The plan of this study of the Maine granites provided for both the scientific and the economic phases of the subject, and it is believed that the author has succeeded in making this report an important contribution along both these lines.

Discussion of the granites and associated rocks from a purely petrologic standpoint has been omitted, and no chemical tests have been made except as the chemical composition is believed to affect the durability of the stone.  The observations on the relation of the bands of knots to flow structure in the granite, on the parallelism of banding with sheeting and rift, on the relation of sheeting to the surface of the rock, on the cause of the sheeting, and on the spacing and distribution of joints furnish data of high scientific value, which can be used by the geologist interested in the physics of intrusion.  Several of these same observations can be utilized by the quarry superintendents also.  For example, the value of a quarry site is largely dependent on the joint system, and an understanding of the distribution of knots or other imperfections in the stone will guide quarry operations.  The discussion of the cause of the discoloration termed "sap" also has a practical value, as well as the suggestion as to the use that can be made of granite so discolored.

The arrangement of the data presented in this report is believed to favor its use by all classes of readers.  The broader facts of the classification and description of the main granites are separated from the local details of individual quarries.  The endeavor has been to present all the essential facts relating to the granites of Maine, so that the report will be of value to geological students as well as to architects, contractors, and quarry owners.  It is the plan to follow this publication with similar bulletins by the same author describing the granites of other parts of New England, so that together these will furnish an authoritative report on the granite of this area, which produces over 60 per cent of the granite output of the country.

Importance of The Industry.

The statistics of production given on pages 183-184 of this report indicate the valuation that should be placed upon the granite industry of Maine.  In a single county the product of the granite quarries annually reached the value of $1,000,000.  For the whole State the output for 1905 exceeded that for any previous year, its value reaching nearly $2,750,000.

Vermont and Massachusetts are the only other States whose granite production approaches that of Maine.  Both of these, as well as several other States, lead Maine in the value of monumental granite produced, so it is on the output of building stone that the preeminence of Maine depends.  The value of Maine granite quarried in 1905 for building purposes was over $2,000,000, while in the item of dressed granite of this character the production was valued at $1,648,687, or nearly one-third of the output of the whole country.  The next most important product of the Maine Granite quarries is paving blocks, the amount being over one-seventh of that of the United States, and exceeded only by the output of Wisconsin.

As is shown in this report, the basis of Maine's granite industry is largely the position of quarry sites at tide water.  This accessibility of granite of the best grade makes it possible for the Maine product to be an important factor in the markets for building material in the cities of the Atlantic seaboard.  Some quarries, both on the coast and inland, furnish building stone and monumental granite of such quality that their product is in special demand.  With these advantages the granite industry in Maine deserves consideration as one of the most important assets of the State.

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The success of an industry that deals directly with any natural material must involve sooner or later, at some point, a knowledge of the laws pertaining to that material.  Moreover, persons engaged in such an industry are led by their very occupation to seek, with an interest that is in proportion to the intelligence, an explanation of the phenomena that daily come before them.  For these reasons it has been the writer's aim to make the following report both economic and scientific.  Indeed, its scientific part forms to a large extent the basis of its economic part.  In the scientific discussion the presentation is succinct.  Details that are of interest to the scientific specialist alone have been omitted or very briefly summarized, and technical terms have been, as far as possible, avoided.  Such scientific terms as have been necessarily used are explained in the glossary at the end of the report, where, also, some of the quarrymen's terms are given and translated for the benefit of the general reader.

For the general geological knowledge that underlies this report the writer is indebted to a considerable body of scientific literature.  The works of Archibald Geikie, G. P. Merrill, Julien, A. Rosiwal, Buckley, and Watson have been carefully consulted.  Other authorities for particular facts or theories will be named at the proper places.  The design is to present the subject in the light of present science and in simple form.

The material for the local details and descriptions given in this report was collected in three months in 1905, during which time the writer visited 129 quarries and prospects.  Although the complexity of the subject would have justified more extended research at the quarries, it was for several reasons impracticable to extend the season's field work.

Mr. Albert Johannsen, of the United States Geological Survey, has verified or corrected the writer's microscopic determinations of 53 thin sections of typical rocks for this report; Mr. E. C. Sullivan, of the Survey, has made 10 determinations of carbonate in granite, and Mr. W. T. Schaller, also of the Survey, has determined 2 minerals.  Mr. Wirt Tassin, assistant curator of the National Museum, has made an analysis and report on a new mineral from a quartz vein, and Dr. George P. Merrill, head curator of geology of the same institution, has determined a feldspar from the Waldoboro quarry.  Mr. G. K. Gilbert, geologist of the United States Geological Survey, has contributed an important photograph (Pl. VII, A), bearing upon origin of sheet structure in granite, with an explanatory note.  Prof. James F. Kemp, of Columbia University, has kindly made some bibliographical contributions.  The statistical table of granite production in Maine was prepared by Miss Altha T. Coons, of the Survey.

The word "granites," in the title, is used primarily in its popular and commercial sense, and included also the so-called "black granites."  The proper scientific names of the rocks thus designated are given in the sections devoted to classification to the descriptions of the quarries and their products.

(Part I: Scientific Discussion will not be included in this document at this time.)

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