BOOKS BY EDWIN C. ECKEL Building Stones and Clays: their Origin, Characters and Valuation. 8vo, xiv + 262 pages, 37 figures. Cloth, $3.00 net. JOHN WILEY & SONS, New York, 1912. Cements, Limes and Plasters; their Materials, Manu- facture and Properties. 8vo, xxxiv+yis pages, 165 figures, 254 Tables. Cloth, $6.00, net. JOHN WILEY & SONS, New York, 1905. Cement Materials and Industry of the United States. Bulletin No. 243, U. S. Geological Survey. Svo, 395 pages. Washington, 1905. (Out of print.) The Portland Cement Industry from a Financial Standpoint. Svo, 93 pages. MOODY PUBLISHING Co., New York, 1908 The Portland Cement Materials of the United States. Bulletin No. . . . , U. S. Geological Survey. Svo. Washington. (In Press.) BUILDING STONES AND CLAYS: THEIR ORIGIN, CHARACTERS AND EXAMINATION BY EDWIN C. ECKEL, C.E. 4 | ASSOCIATE, AMERICAN SOCIETY OF CIVIL ENGINEERS MEMBER, SOCIETY OP CHEMICAL INDUSTRY FELLOW, GEOLOGICAL SOCIETY OF AMERICA FIRST EDITION FIRST THOUSAND NEW YORK JOHN WILEY & SONS LONDON: CHAPMAN & HALL, LIMITED 1912 3 COPYRIGHT, 1912, BY EDWIN C. ECKEL, C.E. Stanhope jpress F. H. GILSON COMPANY BOSTON. U.S.A. To PROFESSOR T. NELSON DALE Whose work on slates and granites has at last given American economic geology adequate representation in that field. Cm. ifi 257977 PREFACE THE present volume may in some sense be considered as an outgrowth of the author's previous work on cementing materials, for it deals with natural materials which are closely related, either as constituents or as competitors, to the manufactured products therein discussed. It may be noted that little space has been devoted to a de- scription of the local distribution of building stones and clays. The inclusion of such data, relative to products which are nat- urally so common and so widely distributed, tends to convert a general treatise into a mere directory of the quarry and clay product industries. The extensive reference lists which are pre- sented, however, will serve to point out where information re- garding the stone or clays of any particular state may be found. Attention should also be directed to the chapters relative to the examination and valuation of clay and stone properties. So far as known to the writer, most of the material therein pre- sented has not been touched upon in earlier works on these subjects. EDWIN C. ECKEL. WASHINGTON, D. C. January 13, 1912. TABLE OF CONTENTS PAGE Preface v Table of contents vii List of illustrations xiv PART I. BUILDING STONES. CHAPTER I. THE ORIGIN AND STRUCTURE OF ROCKS. The engineering applications of geology 1 Outline of earth history 1 Relative age of rocks 3 Geologic chronology 3 The geologic/viewpoint 4 Kinds of rocks 5 Metamorphism of rocks 6 Conventional symbols for rock classes 6 Chemical relationships of the rock classes 7 Genetic relationship of the rock classes 8 The structures of rocks 11 Inclination of beds; dip and strike 11 Rock folds 12 Faults in strata 13 Joints 14 Suggestions for geologic reading 16 CHAPTER II. IGNEOUS ROCKS IN GENERAL. Origin of igneous rocks 17 Modes of occurrence 17 Texture of igneous rocks 20 Structure of igneous masses 22 Chemical composition 22 Mineral constituents 24 Quartz 25 The feldspars 25 The micas 26 Amphibole-pyroxene group 27 Olivine or peridot 28 Secondary products 28 Classification of igneous rocks 28 Commercial classification 30 vii viii TABLE OF CONTENTS CHAPTER m. GRANITES AND OTHER ACID IGNEOUS ROCKS. PAGE Scope of the term granite 32 Origin and mode of occurrence 33 Origin of granites 33 Modes of occurrence 33 Mineral constitution 33 Chief constituent minerals 33 Identification of constituents 34 Relative proportions of minerals 34 Color of granites 35 Structure and texture 37 Coarseness of crystallization 37 Laminated or gneissoid structure 37 Sheet structure 39 Rift and grain 39 Value of microscopic work 41 Chemical composition of granites 41 Value of chemical work 41 Normal composition of granite 42 Analyses of granites 43 Physical properties of granites 55 Density and weight 55 Compressive strength 55 Transverse strength 60 Geological distribution of granites 60 Production of granite in United States 61 References on granites 68 CHAPTER IV. TRAP ROCK AND OTHER BASIC IGNEOUS STONES. Scope of term trap rock 70 Occurrence of trap rocks 70 Color 71 Mineral constitution 71 Identification of constituents 72 Chemical composition 72 Analyses of trap rocks 73 Physical properties 76 Uses of trap rock 77 Production of trap rock in the United States 78 References on trap rock 80 CHAPTER V. SERPENTINE AND SOAPSTONE. Relation of serpentine to soapstone 81 Serpentine 81 Serpentine, ophicalcite and ophimagnesite 81 Origin of serpentines 82 Chemical composition of serpentine 83 Defects of serpentine 85 TABLE OF CONTENTS ix PAGE Physical properties 85 Distribution of serpentine 86 References on serpentine 87 Soapstone and allied products 87 Origin and composition of soapstone . . '. . 87 Distribution and production 88 References on talc and soapstone 90 CHAPTER VI. SEDIMENTARY ROCKS IN GENERAL. The basis for classification 91 Classes of sedimentary rocks 92 Degree of consolidation 92 Modes of origin of sediments 92 Characteristic sedimentary structures 93 Metamorphism and its effects 93 Normal order of discussion of the sedimentary rocks 93 CHAPTER VII. SLATES. Origin and composition 95 Origin of slates 95 Average composition of slates 96 Average composition of shales 97 Comparison of slate and shale composition 98 Origin and composition of igneous slates 99 References on origin and composition of slates 101 Analyses of American and foreign slates 102 Color, texture and structures 108 Color of slates 108 Economic importance of color 109 Cleavage 110 Physical properties and testing Ill Desirable properties of slate Ill Specific gravity of slates 112 Merriman's tests of roofing slates 112 References on properties and tests of slate 112 Distribution and production of slate 113 Geologic distribution of slates 113 Geographic distribution of slates 113 Chief American quarry districts 114 Chief foreign districts 115 Dressing of roofing slates 115 Measurement of roofing slates 119 Sizes of slates 120 Thickness 121 Statistics of production in United States 122 Imports and exports of slate 125 References on slate deposits 125 X TABLE OF CONTENTS CHAPTER VIH. SANDSTONES. PAGE Scope of term sandstone 127 Origin and composition 127 Origin of sandstones 127 Origin of tuffs 1 128 Chemical composition of sandstones 128 Value of chemical work 129 Interpretation of the chemical analysis 129 Analyses of American sandstones 131 Texture and physical properties 137 Shape and size of grain 137 Composition of the cementing material 137 Value of microscopic work 137 Physical properties of sandstones 138 Working classification of sandstones 142 Necessity for subdivision 142 (a) Quartzites and quartzitic sandstones 142 (b) Gray wackes and dense flagstones 143 (c) Normal sandstones 143 (d) Porous sandstones 143 Geologic distribution of sandstones 143 Production of sandstone in United States 144 References on sandstones ., 148 CHAPTER IX. LIMESTONES. Origin and chemical composition 150 Origin of limestones 150 Shells as sources of limestone 151 Chemical composition of limestone 152 Presence of magnesia 152 Presence of impurities 153 Average composition of limestones 154 Analyses of American limestones 155 Physical characters and tests 156 Texture and structure 156 Color 156 Varieties of limestone 157 Physical characters 157 Compressive strength 158 Distribution and production 159 Geologic and geographic distribution 159 References on limestone distribution 160 Production of limestone in the United States 162 CHAPTER X. MARBLES. Varieties of marble 166 Highly crystalline marbles 166 Origin and character 167 TABLE OF CONTENTS XI PAGE Chemical composition -. 167 Physical properties 172 Production 174 References 175 Fossilif erous or sub-crystalline marbles 177 Origin and character 177 Chemical composition 177 Geological distribution 178 Geographic distribution 179 Production 179 References 180 Onyx marbles 180 Origin and character 180 Uses and production 181 References 181 CHAPTER XI. FIELD EXAMINATIONS AND VALUATION OF STONE PROPERTIES. Field examination of stone properties 182 Scope of reports 182 Exploration required 183 Schedule for notes 184 Points to be examined 185 Grain 185 Color 186 Joints 186 Impurities . 187 Segregations and dikes 187 Weathering 188 Valuation of stone properties 189 Engineers' responsibility for flotations 189 Present status of the stone industry 190 Average costs and profits 190 Financing of the future 191 Characteristics of industrial bonds 191 Raw materials as a basis for bond issues 192 Stock issues against quarry projects 193 CHAPTER XII. LABORATORY TESTING OF STONE. Trend of testing methods 195 Data required from tests 196 Classes of tests applied 197 I. Tests to determine composition and structure 197 Chemical tests 197 Microscopic examination 198 II. Tests to determine density 198 Specific gravity, weight and porosity 198 Xll TABLE OF CONTENTS PAGE Interrelation of these properties 198 Methods of determining weight per cubic foot 200 Porosity 201 Value of density tests 201 III. Tests to determine durability 202 Expansion from temperature changes 202 Absorption 203 Frost tests 203 The Brard test with sodium sulphate 205 Resistance to acids 207 Resistance to fire 210 IV. Tests to determine strength 214 Crushing strength 214 Transverse strength 216 Hardness 216 List of references on testing of stone 216 PART II. CLAYS. CHAPTER XIII. CLAYS: GENERAL CLASSIFICATION. Definition of clay, shale and slate 218 Origin of clays: general statement 219 Classification based on origin 219 (a) Residual clays 219 (b) Transported clays 220 CHAPTER XIV. RESIDUAL CLAYS. Origin of residual clays 221 Residual from decay of igneous rocks 221 Residual from decay of shales or slates 224 Residual from decay of limestone 227 CHAPTER XV. TRANSPORTED CLAYS. Origin of transported clays 231 Water-borne or sedimentary clays 231 Marine clays 231 Marine clays proper 231 Shales 232 Slates 233 Stream clays 233 Lake clays 234 Ice-borne or glacial clays 234 Wind-borne or eolian clays 234 List of references on origin of clays 236 CHAPTER XVI. DISTRIBUTION OF CLAYS. Geographic distribution of clays 238 List of references on distribution of clays 24Q TABLE OF CONTENTS xiii CHAPTER XVH. FIELD EXAMINATION OF CLAY DEPOSITS. PAGE General conduct of field work 244 Use of geological reports 244 Effect of kind of clay on methods of work 245 Examination of shale deposits 247 Examination of soft clay deposits 247 Dealing with known deposits 248 Methods of boring 249 The auger in light work 249 The auger in heavy work 252 References on methods of field examination 257 Determination of composition and tonnage 257 Errors in sampling 257 Estimation of tonnage 258 LIST OF ILLUSTRATIONS FIQ. PAGE 1. CONVENTIONAL SYMBOLS FOR ROCK-CLASSES 7 2. ANGLE OP DIP IN STRATA 12 3. SYNCLINE AND ANTICLINE 13 4. FOLDS WITH INCLINED AXES 13 5. COMPRESSED FOLDS 13 6. ORIGIN OF THRUST FAULTS 14 7. FAULTS IN STRATA 14 8. JOINT PLANES 15 9. GRANITE Boss 18 10. LACCOLITH AND INTRUDED SHEETS 19 11. VOLCANIC NECK, CONE AND SURFACE FLOW 20 12. DIKES AND SHEET OF IGNEOUS ROCK 20 13. DIKES MADE PROMINENT BY WEATHERING 21 14. LAMINATION AND JOINT PLANES IN GNEISS 38 15. SHEET STRUCTURE IN GRANITE 40 16. COLUMNAR STRUCTURE OF TRAP 71 17. SLATE DRESSING; THE DRESSING SHANTIES 116 18. SLATE DRESSING; BEGINNING OF SCULPING 116 19. SLATE DRESSING; SCULPING 117 20. SLATE DRESSING; SPLITTING 118 21. METHOD OF LAYING ROOF SLATES 119 22. CONCENTRIC WEATHERING OF GRANITE 187 23. BOULDERS FROM DECAY OF IGNEOUS ROCK 188 24. INCLINED SHALE BED, WEATHERED TO CLAY 225 25. INTERBEDDED SHALES AND LIMESTONES 226 26. EFFECT OF WEATHERING ON INTERBEDDED SHALES. 4 226 27. HORIZONTAL BEDS OF SHALE-CLAY 226 28. FORMATION OF RESIDUAL CLAY FROM LIMESTONE 228 29. RESIDUAL CLAYS FROM CHALK 228 30. RESIDUAL CLAYS FROM LIMESTONE 229 31. RIVER TERRACES 233 32. CLAY TERRACES ALONG HUDSON RIVER 235 33. PHYSIOGRAPHIC REGIONS OF EASTERN UNITED STATES 239 34. BASIN DEPOSIT OF CLAY 245 35. INTERBEDDED SANDSTONES AND SHALE-CLAYS 246 36. BASIN OR LENS-SHAPED CLAY DEPOSIT 248 37. EXAMINATION OF TERRACE DEPOSIT OF CLAY 253 x v BUILDING STONES AND CLAYS PART I. BUILDING STONES. CHAPTER I. THE ORIGIN AND STRUCTURE OF ROCKS. The Engineering Applications of Geology. The geology of a region bears upon the work of the engineer in three different ways, through its influence, respectively, on the topography, structure and materials of the given area. (1) The topography of the district, on which depends the loca- tion of both drainage lines and transportation routes, is directly related to the geologic history of the area. (2) The underground structure determines the accessibility of industrially valuable mineral deposits, as well as the occurrence of underground water supplies. (3) The rocks and minerals present in any given area will usually contribute, either directly or indirectly, to the supply of materials available for structural work, and for other purposes. With these facts in view, it is evident that the relations to engineering of structural and economic geology are very intimate. In the present volume, which deals with two of the more im- portant groups of structural materials used by the engineer, we are concerned chiefly with a study of the manner in which certain raw materials have been made available for use. Before, how- ever, taking up these particular raw materials in detail, it will be well to briefly summarize the main features of what may for convenience be termed Engineering Geology. Outline of Earth History. For our present purposes it is sufficiently accurate to assume that the earth, in the earliest stage of its history requiring consideration, was a fused mass, of approximately spherical shape, cooling slowly from the ex- terior inwards, and surrounded by an envelope of gases. When the cooling had progressed far enough, the earth's exterior and 1 2 BUILDING STONES AND CLAYS center solidified gradually a surface or crust of igneous rocks being formed while local differences in the rate of cooling caused irregularities in this surface. Combinations of the cool- ing gases caused the precipitation of water, in the form of rain; and with the action of the first surface water began the formation of the sedimentary rocks. The fallen rain gathered in slight depressions of the crust to form the earliest streams and rivers; and followed these courses to deeper depressions which formed the earliest seas and oceans. In its course the water, whether raindrop or stream, carried off small portions of the rocks it encountered, transporting them either mechanically or in solu- tion, and depositing them finally as sediments. This process has continued to the present day, a steady supply of detritus being carried to the seas; and it is obvious that some counter- balancing process must act to prevent all the lands being worn down to sea level. This compensatory action is evidenced by the gradual depression, at intervals, of portions of the sea bottom (overloaded with deposits of sediment) and the consequent rela- tive elevation of the land areas. The process is therefore con- tinuous, forming a regular three-phase cycle, the phases being (1) erosion of high lands by running water; (2) deposition of the resulting detritus on the sea bottom; (3) overloading and con- sequent depression of parts of the sea bottom with a corre- sponding relative elevation of the land and the recommencement of erosion. At intervals in the earth's history these regular cyclical changes have been aided or retarded by less regular occurrences. Masses of fused rock have been forced up from the interior to cool at or near the surface; heat and pressure have caused great changes in deeply buried rock masses; minor movements in the crust have caused folds, faults and joints in the rock series; and once at least temperature changes have caused a glacial period in the temperate zone. So far as these phenomena concern the engi- neer they will be discussed in later paragraphs. Life was, so far as known, existent before the formation of our earliest identified sedimentary rocks. Through the following ages it has, however, greatly changed in form and type; and this gradual evolution in living organisms aids in determining the relative ages of the rocks in which their fossil remains are now inclosed. THE ORIGIN AND STRUCTURE OF ROCKS 3 Relative Age of Rocks. The geologist, confronted with a finished product a given tract of country endeavors to work out its history. Usually the first step in this direction will be to map the areas covered by different kinds of rock, but along with this areal mapping he must carry on studies to determine the relative age of the various rock formations which occur within the limits of the tract under consideration. In doing this the following criteria are of most service. (a) Superposition. Since sedimentary rocks are surface de- posits, it is obvious that of two series of sedimentary rocks, the overlying series must be the younger, provided that no serious earth movements have altered their relative position since they were deposited. (b) Contained Fragments. If one rock formation contains pebbles or other fragments of material evidently derived from another formation, the fragment-containing bed must have been formed after the other had been deposited. (c) Contained Fossils. This, which is usually the most exact and positive criterion of all, is not immediately evident like the preceding two. In the progress of geologic science, it has been determined that beds of certain age are characterized by certain assemblages of fossil remains. Comparison of the fossils found in the beds of the area under study with those found in some area where the succession is already known, will therefore fix the relative position and age of the series under study. Geologic Chronology. By the careful application of the criteria briefly described in the preceding section, a fairly com- plete geologic chronology has been gradually worked out to cover the whole extent of earth history. For convenience of reference and comparison, all of geologic time is primarily divided into twelve periods, which in turn are subdivided into epochs. Still more minute subdivisions are stages, while the final unit of division is the formation. This system of subdivision gives a series of time intervals which, taken together, cover all geologic history. The names of the periods are given below in order downward from the most recent (Quaternary) to the earliest (Archaean). In a few cases the subdivisions into epochs are also given. BUILDING STONES AND CLAYS Period Epoch [Quaternary .......... | Cenozoic ..... < f Pliocene Tprtiarv J Miocene |/ertiary ............ 1 Oligocene t Eocene f Cretaceous Mesozoic ...... j Jurassic iTriassic f Permian Carboniferous ....... < Pennsylvanian or Coal Measures (^ Mississippian or Subcarboniferous Devonian Silurian Ordovician Cambrian Paleozoic Pre-Cambrian To the engineer the determination of the geologic age of the rocks of any given district is rarely a matter of importance, except in so far as geologic age may affect the character of the mineral products. It would be folly, for example, to expect to find important workable deposits of coal in rocks older than the Carboniferous period but that is about the only valuable general statement that can be made. In any particular small area, of course, a relation between age and material is more common. The valuable " cement rock" of the Lehigh district of Pennsylvania, for example, occurs in that region only in beds of one particular geologic age, and it would be useless to search for it in rocks of other periods. Another case in point is the red or fossil iron ore, so important to the southern iron industry. This occurs in the eastern United States only in rocks of Clinton age, and the presence or absence of the ore on any particular property can therefore be inferred on purely geologic grounds. In Luxembourg, however, an entirely similar ore occurs in rocks of much later age so that it is evident that such a generaliza- tion is safe only within rather close geographic limits. The Geologic Viewpoint. It is not at all difficult for an engi- neer, confronted with some semi-geologic problem, to master in a short time the principal geologic facts to which he must give consideration. That is merely a matter of application to a rather interesting study. What is difficult, however, is for him to learn to look at these facts from what may be termed the geologic viewpoint. THE ORIGIN AND STRUCTURE OF ROCKS 5 To judge from published reports on water-supply problems and other work involving engineering geology, the tendency is to assume unconsciously that in considering geologic facts it is useless to apply the same type and closeness of reasoning which are essential to the solution of purely engineering problems. The effect of this mistaken attitude is that the engineer too often is inclined to invoke forces and agencies totally unknown to engineering practice in order to aid in solving a geologic problem ; so that the finished report is frequently a curious mixture of clear observation and erroneous interpretation. In considering this matter the engineer will avoid many serious misinterpretations of facts if he bears in mind that: (a) Geologic occurrences are to be explained by reference to the same physical forces which are now in operation running water, winds, frost, terrestrial heat, etc. (6) These forces have, on the whole, always been of about the same degree of intensity; the one prominent exception being the extension, during the glacial period, of intense ice action into the temperate zone. (c) Changes in the earth's surface whether of coast line, relief, or drainage have been almost invariably brought about with extreme slowness. (d) Gorges, canyons, mountain ranges and other striking physi- cal features are therefore due almost always to the long continued action of ordinary familiar physical forces, and not to sudden and violent "upheavals," "volcanic outbursts" or other "con- vulsions of nature." Kinds of Rocks. Rocks are classified, according to origin, in one of two groups: (1) igneous, or (2) sedimentary. In by far the majority of cases there is no difficulty in determining the group in which any given rock should be placed; but at times the decision is more difficult and, in some cases, impossible. (1) The igneous rocks are those which have been formed by the cooling of fused material. The original crust of the earth was of course formed entirely of igneous rocks, but it is highly improbable that any of this original crust is now exposed at the earth's surface. The igneous rocks with which we have to deal are of later origin, being derived from molten material which at different periods has been forced up through and into other rocks. In most cases this molten rock did not reach the surface 6 BUILDING STONES AND CLAYS while fused, but cooled and solidified slowly while covered by thick masses of overlying material, and is now exposed to view owing to the slow removal of this covering. (2) The sedimentary rocks are those derived from the decay of preexisting strata, the material so obtained being carried (usually by water) in suspension or solution to some point where it is redeposited as a bed of sand, clay or limestone. Subse- quently this loosely deposited material may become consolidated and hardened by pressure or other agencies, the result being the formation of sandstones, shales and slates from the original unconsolidated beds of sand and clay. In the later chapters of this volume, which deal respectively with the igneous rocks and the sedimentary rocks, further data will be presented on the characters, origin and subclassification of each of these groups. Metamorphism of Rocks. All rocks are more or less changed or metamorphosed from the condition in which they were first deposited (in the case of sedimentary rocks) or in which they first cooled from fusion (in the case of igneous rocks). The changes are due to the action of heat, pressure and chemical agencies; and the effects may appear in changes of either the physical structure of the rock, its texture or its chemical com- position. As has been said, all rocks have suffered such changes or meta- morphism to a greater or lesser extent, but the term metamorphic rocks is restricted properly to the rocks in which the changes have gone so far as to produce very marked alterations, some- times entirely obliterating the original structure, and at times rendering it difficult or even impossible to decide whether the original rock was of sedimentary or of igneous origin. Conventional Symbols for Rock Classes. In representing the different classes of rocks on geologic cross sections, it is often necessary to adopt different symbols or patterns so as to dis- tinguish between igneous rocks, shales, limestones, etc. Though these symbols are purely conventional, there is a great advantage in having the same symbols adopted by every one for the same rocks, and considerable uniformity in this regard can now be seen in the publications of the various geological surveys. In Fig. 1, the patterns for the different classes of rocks by the United States Geological Survey are shown. THE ORIGIN AND STRUCTURE OF ROCKS II. I Limestones. Shales. Shaly limestones. Sandstones and con- glomerates. Shaly sandstones. Calcareous sandstones. 3fassiye and Taedded igneous "cocks. Fig. 1. Conventional symbols for kinds of rock. Chemical Relationship of the Classes of Rocks. A feature of considerable economic and scientific interest appears to have been overlooked by geologists as well as by engineers. This is the relationship which exists between the chemical composition of the various classes of rocks. It is well brought out in the follow- ing table, which was prepared by combining data published by Professor F. W. Clarke and by the present writer. It will be seen that this table gives average analyses of large series of different rock groups, and the averages may therefore be considered to fairly represent the mean composition of these groups. Examination of the table shows that the average igneous rock is closely similar in composition to the average shale and the average slate. In other words, the shales and slates are made up of fine particles of the same materials which occur in the igneous rocks, and in about the same proportions. Evi- dently little chemical sorting or segregation took place during the formation of shales and slates. With regard to the sandstones and limestones the case is very different. Here there has been 8 BUILDING STONES AND CLAYS a great deal of separation, resulting in the deposition of almost pure silica in the case of sandstones and of lime carbonate in limestones. TABLE 1. AVERAGE ANALYSES OF VARIOUS CLASSES OF ROCKS. 830 Igneous rocks. 78 Shales. 36 Slates. 371 Sandstones. 345 Limestones Silica (SiO 2 ) Alumina (A1 2 O 3 ) * Ferric oxide (Fe 2 O 3 ) .... Ferrous oxide (FeO) .... Lime (CaO) .... 59.71 16.01 2.63 3.52 4 90 58.38 16.12 4.03 2.46 3 12 60.64 18.05 2.25 3.66 1 54 84.86 6.37 1.39 0.84 1 05 5.19 0.87 0.54 n.d. 42 61 Magnesia (MgO) 4 36 2.45 2 60 52 7.90 Soda (Na 2 O) 3.55 1.31 1.19 0.76 0.05 Potash (K 2 O) 2 80 3 25 3 69 1 16 33 Combined water . . 1 52 3 68 3 51 1 47 56 Moisture 1 34 62 27 21 * Including small amounts of titanic oxide (TiO 2 ). In the case of such sedimentary rocks as the sandstones and shales, the entire process is a purely mechanical matter, the materials being carried in suspension by moving water, and being deposited because of decrease in the velocity of the water which has transported them. The limestones, however, present a more complicated case, for the lime and magnesium carbonates of which they are formed are usually carried in solution by water, and are deposited by chemical or organic agencies. These differences in origin and deposition will be taken up in more detail in later chapters, where the various kinds of sedimentary rocks are separately discussed. Genetic Relationship of the Rock Classes. It may aid the reader to comprehend more fully the closely interwoven relation- ships of the various classes of rocks if the discussion be carried a stage further, and some consideration given to their relation- ship so far as origin is concerned. So far as known to the writer, the matter which is here presented has never, even in purely geologic treatises, been set forth in a closely analytical form, though of course the ideas which underlie this analysis are generally accepted. THE ORIGIN AND STRUCTURE OF ROCKS 9 The accompanying diagrammatic table (Table 2) has been prepared to serve as a convenient semigraphic summary of the statements in the following paragraphs, and should consequently be studied in connection with those paragraphs. In order to facilitate this cross reference, the notation used in the table has also been employed to designate the corresponding steps in the more detailed discussion below. I. For our present purpose it will be sufficiently exact to con- sider that, in the earliest stage to which we need refer, the earth's crust was already solidified by cooling, and that it was composed entirely of igneous rocks. These rocks intergraded closely in composition, but for convenience here may be divided into an acid group (I a) and a basic group (I 6). The acid group would include those rocks higher in silica than the average noted on page 8, while the basic rocks would include those lower in silica than the average. The dividing line between the two groups is therefore fixed naturally at about 59 per cent silica. II. The igneous rocks forming the exposed portion of the crust were almost immediately attacked by both mechanical and chemi- cal agencies of destruction. The two sets of agents undoubtedly commenced their destructive action almost simultaneously, but it will be logically exact and certainly conducive to clearness in the present discussion if we at first consider only the effects of purely mechanical attack on the exposed crustal rocks. The effect of heat and cold, rain and running water, on a series of rocks is to ultimately effect the mechanical disintegration of a portion of the exposed outcrop. The material thus broken down mechanically is carried off by running water and finally deposited. Since it is assumed that this entire process has not been assisted by chemical action, and that the material deposited has not been subjected to mechanical concentration or sorting, the ultimate result would be the formation of a bed of sandy clay. In composition this clay would not differ greatly from the average composition of the igneous rock from which its materials were derived. The clays thus formed would be either typically siliceous clays (II a) or basic clays (II 6) according to the character of the particular igneous rocks from which they were derived. III. As a matter of fact, however, both leaching and sorting must have taken place at an early period in the history of the 10 BUILDING STONES AND CLAYS sedimentary rocks. The principal sorting effect would be the mechanical separation of the particles of quartz from the other residual material, owing to the greater resistance of quartz to both mechanical and chemical attack. The sorting out of this quartz and its separate deposition would give rise to the for- mation of beds of sand and gravel (IIIc). The principal effect of chemical attack would be the removal of lime in solution. The lime thus carried off would be redeposited, either through direct chemical action or by the agency of living organisms, to form marl deposits, shell beds, etc. (Hid). TABLE 2. STAGES IN THE ORIGIN OF ROCK CLASSES. Stages of origin. Siliceous. Silico-aluminous. Calcareous. I. Original con- stituents of the earth's crust. la. Acid rocks 1 6. Basic rocks II. Derived from I by mechanical erosion and sedimentation without sorting. II a. Acid clays 116. Basic clays III. Derived from I or II, with the aid of mechanical sorting and chemical leaching. Ill c. Beds of sand and gravel. Ilia. Acid clays III 6. Basic clays Hid. Shell beds, marl deposits, etc. IV. Derived from III by normal consoli- dation. IV c. Sand- stones IV a. Acid shales IV b. Basic shales IV d. Lime- stones V. Derived from IV by metamorphism. Vc. Quart z- ites Va. Acid slates V6. Basic slates Vd. Marbles The mechanical removal of silica and the chemical removal of lime would leave the balance of the residual material still in the class of clays, as III a, and III 6, but somewhat poorer in silica, lime and other soluble constituents than if such sorting and leaching had not taken place. IV. The deposits thus far considered are still to be regarded as relatively unconsolidated beds of material. As these beds were covered by later rocks, pressure, heat and renewed chemical action were gradually brought into play. The result was that THE ORIGIN AND STRUCTURE OF ROCKS 11 the beds of sand and gravel (III c) became ultimately sandstones (IV c) ; the clays (III a and III 6) became shales (IV a and IV 6) ; while the calcareous deposits (III d) became limestone (IV d) . No serious chemical change resulted from this consolidation, so that the rocks of the subgroups of IV are closely akin chemi- cally to the unconsolidated deposits of III from which they were respectively derived. V. In most cases the process of consolidation stopped at the stage which has just been discussed, but locally the consolidating agencies persisted in their work to a point where the physical changes which they caused warrant us in giving another name to the product. Thus the sandstones (IV c), if consolidated very intensely, might locally become quartzites (V c) ; the shales (IV a and IV 6) in places became slates (V a and V 6) ; and the limestones (IV d) in metamorphic regions became marbles (V d) . In these further consolidations the chemical changes which take place are very slight as compared with the purely physical alterations. THE STRUCTURES OF ROCKS. Under this heading will be discussed such structural features as are common to all classes of rocks. Structures peculiar to the igneous rocks will be considered in Chapter II, while those peculiar to the sedimentary rocks will be discussed in Chapter VI. As thus limited, the structural conditions to be considered in the present section include the inclination of beds (dip, strike, etc.); rock folding; faults; jointing and cleavage. Inclination of Beds; Dip and Strike. The beds of sedimen- tary rocks, having been formed for the most part by deposition on the gently sloping bottoms of bodies of water, would naturally have a horizontal or nearly horizontal attitude at the time of their formation. But during the numerous elevations and de- pressions of the land which have occurred since their deposition, this original horizontality of bedding was in many cases de- stroyed, so that now we may find sedimentary rocks whose beds are inclined at all angles to the horizontal. This is particularly true in the Appalachian, Lake Superior, Rocky Mountain and Pacific Coast regions, where horizontal strata are the exception rather than the rule. In the central United States, however, most of the rocks still lie almost or quite horizontal, an inclina- 12 BUILDING STONES AND CLAYS tion of over five degrees being distinctly uncommon in the States of the Mississippi basin. In describing the attitude of a bed inclined to the horizon, it is necessary to do so in terms of dip and strike; which requires that these two terms be defined. The strike of an inclined bed may be roughly defined as the direction or trend of the bed. To be more precise, it is the compass bearing of a straight line drawn horizontally on one of the faces of the bed. The dip of the bed is the angle made with the horizontal by a line drawn on the sur- face of the bed, at right angles to the strike (Fig. 2). Since the two factors are thus related, it is unnecessary to give the exact compass bearing of the dip (for that will always be at right angles to the strike) but merely the quadrant. In description it is therefore sufficient to say, for example, that a rock has a strike of N. 30 E., dip 35 S. E. which can readily be seen to imply that the dip of 35 degrees is in the direction S. 60 E. Though, from a very strict standpoint, the terms dip and strike would be applicable only in describing the bedding planes of sedimentary rocks, there is no real reason for not using them in describing the attitude of the laminated igneous rocks (gneisses, schists, etc.), and they are commonly so applied. Rock Folds. The terms dip and strike having been defined, it is possible to glance at certain broader features of rock struc- ture of which dip and strike are merely local manifestations. These broader features are connected with the subject of rock folding. In the course of earth movements, folds and flexures of various types are developed in beds of rock which may previously have been horizontal. If the movement simply elevates or depresses one side of an area, so that as a result the rocks everywhere dip in the same direction, the resulting attitude of the rocks is called a monocline. If, however, compressive or tensile stresses accom- pany the uplift or depression, a complete fold of some sort will be formed. When a complete fold is presented for observation, it may be either a syncline or trough, in which the strata on both sides dip THE ORIGIN AND STRUCTURE OF ROCKS 13 toward the axis of the fold; or an anticline or arch, in which the strata on both sides dip away from the axis of the fold. Fig. 3 Fig. 3. Syncline and anticline. shows both of these structures, a very sharp anticline being shown at the extreme right of the figure, while a rather flat syncline occupies the remainder of the sketch. Fig. 4. Folds with inclined axes. In the simple forms of these folds shown in Fig. 3, the axes of the folds are vertical in each case, and there is no particular com- pression of the limbs of the folds. In more complex cases we find folds with inclined axes, as is shown by those repre- sented in Fig. 4; or with ex- tremely compressed limbs as shown in Fig. 5. Faults in Strata. When, in the course of earth move- ments, the strata subjected to stress are too rigid to yield by simple folding, or when the stress is applied too rapidly, they will yield by fracture. Such fractures, which may occur at any point in the stressed area, result in the for- mation of a fault, which may be considered simply as a break in / / /V: '/' ' ' i 7 77' I ' I ,' '1 I i ' /////// //// Fig. 5. Compressed folds. 14 BUILDING STONES AND CLAYS the continuity of the strata, accompanied by elevation or de- pression of the beds on one side of the fault plane. Fig. 6. Origin of thrust faults: a, overturned fold in rocks, passing by frac- ture into b, thrust fault. On a large or small scale, faulting is a very common phenome- non, particularly in regions of intense folding. It is a matter of peculiar economic importance to the mining engineer, since the existence of faults in a district complicates the underground structure, and renders it difficult to follow out a mineral deposit affected by faulting. For our present purposes, however, the subject of faulting requires little consideration, for no engineer would consider opening a structural stone quarry in a badly faulted area. On the other hand, the existence of numerous faults might be a distinct advantage in operating a quarry for crushed stone. Fig. 7. Faults in strata: a, original attitude of strata; 6, position after normal faulting; c, position after reverse faulting. Joints. A sedimentary rock, as originally deposited, would probably show more or less distinct bedding planes (see page 93), and would have a tendency to break or split parallel to these planes. But it would not have any planes of easy fracture transverse to the bedding planes, for in this direction the stone would be entirely homogeneous and massive. Igneous rocks, cooled entirely without interference, would be even more homo- THE ORIGIN AND STRUCTURE OF ROCKS 15 geneous; and would not show planes of easy fracture in any direction. As a matter of fact, however, both sedimentary and igneous rocks do commonly show certain planes (entirely distinct from the bedding planes in the case of the sedimentary rocks), along which they break or cut with greater ease than in any other direction. When these planes are so marked as to show on the surfaces of the rock, dividing it into more or less rectangular Fig. 8. Joint planes in sandstone. (Photo by E. M. Kindle.) masses, they are described as joints (Fig. 8) . When the fracture planes do not show on the surface, but merely exist as planes of weakness within the rock itself, we have the rift and grain which are discussed in a later section (page 39) in describing the struc- ture of granites. Recurring to the subject of jointing, the examination of a quarry will show almost invariably that the rock breaks out in rectangular or prismatic blocks; and that the surfaces which bound these blocks are parallel to one or more systems of joints. As to origin, joint planes may be due to cooling stresses (in 16 BUILDING STONES AND CLAYS the case of igneous rocks); to drying, in the case of sediments; or to earth movements after deposition, in the case of either igneous or sedimentary rocks. SUGGESTIONS FOR GEOLOGIC READING. The subjects discussed in this chapter may perhaps be com- pleted most profitably by a brief reference to a few books dealing with various phases of engineering geology in more detail than has been possible here. The writer has no intention of outlining a course of geologic study, but will simply note the lines along which further reading may be useful to the engineer desirous of securing a working acquaintance with both geologic theory and practice, so far as they affect his own work. 1. As to general geology, one of the more elementary text- books, such as those of Tarr or Brigham, will in most cases be more satisfactory than a larger treatise. The best manual, of course, is the Geology of Chamberlin and Salisbury, but this is too bulky, too detailed and too expensive to be generally serviceable. 2. The next stage is some degree of acquaintance with the field practice of geology, including knowledge of the facts which should be observed and of the methods adopted in noting, recording, and interpreting these facts. In this field Geikie's Structural and Field Geology is still unsurpassed as a general guide for field work; while Grenville-Cole's A ids in Practical Geology contains valuable data relative to the rocks, minerals, and fossils which may require determination. Both of these books are English, and therefore much of their illustrative matter will be unfamiliar to the American reader; but in spite of this drawback Geikie's book at least can hardly be dispensed with. 3. Further study of the structures and classification of rocks, and of the processes involved in their origin and decay, will fortunately be aided by two books which are at once readable and authoritative. Reference is here made to Kemp's Hand- book of Rocks and to Merrill's Rocks, Rock Weathering, and Soils. The two do not cover exactly the same ground, but supplement each other admirably. Of the two, Kemp's book should be taken up first, and is probably of more general service; but Merrill's volume has a more direct bearing on the problems in- volved in the weathering and decay of building stone. CHAPTER II. IGNEOUS ROCKS IN GENERAL. IN the previous chapter the origin and characters of the igneous rocks have been briefly noted, but only as connected with the relationships of the various rock classes, and not in the detail required by their industrial importance. In the present chapter the more important characteristics common to all igneous rocks will be discussed in such detail as seems advisable, while the special characteristics of the granites and traps will be taken up in the later chapters in which these two commercial subgroups of the igneous rocks are described. Origin of Igneous Rocks. According to the more commonly accepted theories, the entire earth was at one time a molten mass; and at least part of its interior is still either fluid or on the verge * of fluidity. The igneous rocks, as now found at the surface, comprise the materials which have solidified and crys- tallized by cooling from this state of fusion. The solid crust first formed on the cooling earth was of course composed entirely of igneous rocks, and it is possible (though highly improbable) that portions of this original crust are still exposed at various points on the present surface of the earth. Most of the igneous rocks, however, have solidified at later periods of the earth's history, having been forced upward into or through the over- lying rocks, and having passed upward until they reached a point at which decreased pressure and lowered temperature have allowed the molten material to cease its movement, to cool and to crystallize. Modes of Occurrence of Igneous Rocks. Both scientific and economic interest attach to a study of the modes in which igneo.us * In explanation of this, it is clear that the pressure of overlying rocks may be sufficient to keep the interior in a solid condition, even though the tempera- ture in the depths may be above that which would be required to melt these rocks if they were at the surface. Under these conditions, any release of pressure will, of course, immediately permit the highly heated rock material to become fluid. 17 18 BUILDING STONES AND CLAYS rocks have reached their present condition at the earth's surface, so that attention can properly be directed to a brief discussion of the principal modes of occurrence. For our present purposes, the principal types which require consideration are the following: Fig. 9. Granite boss rising above limestone plain. (Photo by E. C. EckelJ 1. Stratiform Masses. It would of course be incorrect to apply the term " stratified " to igneous masses, for owing to their origin the term would be obviously a misnomer. But on all the continents it is found that the Archaean rocks are com- posed largely of igneous materials. These include both basic and acid rocks, and vary in structure from entirely massive to thoroughly gneissoid types. It is impossible to prove at present that these Archaean igneous rocks were ever intruded into other formations. In most cases all that can be said about their mode of occurrence is that they now exist, covering immense areas on the earth's surface, and serving as a basement or floor on which the earliest known fossiliferous rocks were deposited. Because of the facts that they can be separated into different formations, IGNEOUS ROCKS IN GENERAL 19 that they have no definite relation to sedimentary rocks of the same date, and that they are generally thoroughly laminated and folded, it is convenient to use the term stratiform masses in describing them. 2. Batholiths. Along the axes of many mountain chains are found vast masses of granitic and other igneous rocks, evidently intruded into existing sedimentary deposits, but having cooled at a considerable depth below the surface of the earth. These cores or batholiths are now exposed at the surface simply because the sedimentary rocks which once overlay them have been removed by erosion. Smaller masses of the same general type, weathered out so as to project above the general surface level, are referred to as bosses or stocks. One of these is illustrated in Fig. 9. 3. Laccoliths. The two types of rock mass which has been discussed above agree in that their cooling took place so far below the surface that the nearness of the latter had no effect on the shape of the mass or on the texture of the rock. In the modes of occurrence which remain to be discussed this was not the case. Fig. 10. Laccolith, with supply neck (A) and sheets (B). A mass of heated igneous rock, rising upward through approxi- mately horizontal existing strata from a molten reservoir might conceivably reach a point at which it would be easier to force the overlying strata up into a dome or arch rather than to break away through them. The igneous rock, cooling in the arched cavity thus formed, would take the form of a laccolith. In Fig. 10 a typical laccolith is shown in cross section, together with some of the phenomena which usually accompany it. 4. Volcanic products. If the igneous rock penetrated to the surface, and issued at some particular point of weakness, a volcano 20 BUILDING STONES AND CLAYS would be formed. As shown in Fig. 11, this would usually in- volve the creation of the volcanic neck or passage through which the igneous rock reached the surface, the subsequent building of a cone of ashes or lava, and in some cases the flow of a more or less extensive lava sheet over the adjoining surface. Fig. 11. Volcanic neck (A), cone (B) and surface flow (C). 5. Dykes, Sheets and Sills. Certain minor types of occurrence, which may be connected with either volcanic or intrusive action, remain to be noted. Igneous rock might reach upward toward the surface through approximately vertical fissures. The rock which cooled in these fissures would form a dyke, as illustrated in Figs. 12 and 13. If at any point a supply of igneous rock penetrated laterally along the bedding planes of a sedimentary formation, it would form on cooling an intrusive sheet or sill. Examples of these are also shown in Figs. 11 and 12. A A A Fig. 12. Dykes (A, A) and sheet or sill (B). Texture of Igneous Rocks. When molten masses cooled in large bodies, or at considerable depths below the surface, the solidification was in consequence so slow as to permit the forma- tion of large crystals of the different constituent minerals. Our ordinary granites are good examples of such slowly cooled prod- IGNEOUS ROCKS IN GENERAL 21 ucts. But when the local supply of molten material was small, or when solidification took place at or near the surface, the cool- ing was so rapid that the resulting rocks are made up of very small mineral crystals, often enveloped in a glassy matrix; while Fig. 13. Dykes made prominent by weathering. (Hayden Survey.) a still more rapid cooling might result in a rock having an entirely glassy structure, absolutely free from crystals. If, as happened in places, the igneous material was introduced into the air or into water while still molten (as in volcanic action), the result was the formation of porous products volcanic ash, pumice, etc. Perhaps the conditions above outlined may be more clearly realized if they are compared with a parallel series of perfectly BUILDING STONES AND CLAYS familiar phenomena which occur every day in the handling of slag at blast furnaces. If furnace slag is cooled with very great slowness, it will develop crystals of various silicate minerals. On the other hand, the slag as it usually cools on a slag bank has an entirely glassy texture. Finally, if the molten slag is led into water, or if a current of steam, air or water is injected into the stream of molten slag, the slag will cool or granulate so suddenly as to assume a porous texture, exactly like a volcanic ash. Structure in Igneous Rocks. Since all igneous rocks are formed by direct cooling from a state of fusion, it is obvious that none of them can show any true bedding, for that is a charac- teristic of materials deposited by or in water. The differences in structure can not be due to the sorting influence of water, but must be entirely due to the varying conditions under which they cooled, or to the effects of later earth movements on the cooled mass. Considering igneous rocks in general, two different types of structure may exist. 1. In an igneous rock which has solidified quietly from a fused state, and which has not been later subjected to severe external stresses, the constituent mineral crystals are confusedly arranged, showing no trace of parallel banding or lamination. Such rocks are termed massive igneous rocks. Most of the granites used for structural purposes, and practically all of the trap rock used commercially, fall in this class. 2. If, however, rocks of this same origin and composition had been subjected, either during or after their cooling, to external pressure, a laminated structure might have been developed. When this has occurred under favorable conditions the con- stituent minerals may be arranged in more or less definite alternating bands; while when the lamination is less completely developed the mineral crystals will merely be arranged with their longer axes in the same direction. In either case the rock is termed a gneiss. Some of the rocks which commercially are classi- fied as granite, and are used in structural work, are in reality suffi- ciently well laminated to be properly called gneisses. Chemical Composition of Igneous Rocks. The igneous rocks consist largely of silica from 35 to 80 per cent with lesser amounts of alumina. According to their class they may also contain more or less iron oxides, lime, magnesia, potash and IGNEOUS ROCKS IN GENERAL 23 soda. These are the principal constituents which are present, in varying amounts, in practically all of the igneous rocks. Many other constituents are present in small percentages, but are of little general importance and do not require further notice here. Such wide variation exists in the composition of the different types of igneous rocks, that few general statements can be made which will apply to the group as a whole. Analyses of these various rock types will be given later, in the chapters dealing with them separately, but in the present place attention may be called to the data presented in Table 3. This table includes averages, of two long series of analyses of igneous rocks; and the two results may fairly be regarded as closely representative of the composition of the average igneous rock. TABLE 3. AVERAGE ANALYSES OF IGNEOUS ROCKS. Constituent. A. B. Silica (SiO 2 ) Per cent. 59 71 Per cent. 58 75 Alumina (A1 2 O 3 ) * 16 01 15.76 Ferric oxide (Fe2O3) 2 63 5 34 Ferrous oxide (FeO) 3 52 2 40 Lime (CaO) 4 90 4.98 Magnesia (MgO) 4.36 4 09 Potash (K 2 O) 2.80 2.74 Soda (Na 2 O) 3.55 3.25 Water . 1 52 2 23 * Including small amounts of titanic oxide (TiOj). A. Average by F. W. Clarke, of 830 analyses of American igneous rocks. B. Average by Barker, of 397 analyses of British igneous rocks. The terms acid and basic, as often applied to igneous rocks, require some note. Acid rocks are those containing high per- centages of silica and low percentages of lime, magnesia, alkalies and iron oxide. Basic rocks, on the other hand, are high in iron, magnesia, etc., and comparatively low in silica. The two classes intergrade with each other and the dividing point between the acid and the basic rocks is fixed by different writers at different percentages of silica. Certainly, acid rocks must in average com- position contain more silica than basic rocks: but the dividing line is purely arbitrary. It is both convenient and logical to use the average analyses presented in the preceding table as a basis for fixing this dividing point, and to consider that any igneous 24 BUILDING STONES AND CLAYS rock higher in silica than the average is an acid rock, while any rock lower in silica than the average is a basic rock. In the present volume, therefore, when it is necessary to use these terms precisely, the dividing point between the two classes will be considered to be 59 per cent of silica. The differences in chem- ical composition cause differences in physical characters. Certain acid rocks may, in average density, range higher than exceptional basic rocks: but in general the acid rocks are distinctively lighter than the basic. Mineral Constituents of Igneous Rocks. The igneous rocks which have crystallized out completely are composed of an inti- mate mechanical mixture of various silicate minerals. Those in which the cooling has been too rapid to permit of thorough crystallization consist more or less entirely of a formless silicate glass. Since this latter class can not be identified by mineral composition, the paragraphs which immediately follow must be understood to relate only to such igneous rocks as are entirely or largely crystallized. The total number of mineral species which may occur in igneous rocks is very large; but only a few of these species are of real importance in the present connection. Fortunately the lighter colored coarse-grained rocks which furnish most of our structural stone usually contain few mineral species commonly only three or four are present in quantity and these are readily recognizable. The finer grained or partially glassy igneous rocks, on the other hand, can not be properly classified without the aid of chemical analysis or microscopic investigations; but the rocks of this type are not of high industrial importance for structural purposes. The minerals which make up the bulk of the igneous rocks used for structural purposes represent five species or groups of species. These are in order of importance: (1) Quartz. (2) The feldspars. (3) The micas. (4) The amphibole-pyroxene group. (5) Olivine. Several minor minerals are of sufficient importance to require brief mention, while certain minerals which occur as secondary IGNEOUS ROCKS IN GENERAL 25 or alteration products may also be noted. These will be taken up after describing the five principal groups listed above. (1) Quartz, which is composed entirely of silica (SiO 2 ), occurs in the granites and many other igneous rocks. It is also, it may be noted, the principal constituent of the sandstones. In the granites, quartz commonly occurs as a transparent or translucent mineral, varying in appearance from clear, colorless and glasslike to light grayish or light bluish. It shows no regular, smooth surfaces or fracture planes; but breaks with a rough, irregular, glassy fracture. It can not be scratched with a knife, being hard enough to scratch window glass. The specific gravity of pure quartz is close to 2.65. (2) The feldspars are a group, including a long series of com- plex silicate minerals. The most prominent members of this group are orthoclase, albite, labradorite, anorthite, oligoclase and microdine. The distinctions between the various feldspars can rarely be made out except by chemical analysis; but the group, taken as a whole, can be described quite satisfactorily. The feldspars occurring in most building stones are commonly white to gray or reddish in color more rarely dark blue or gray; on breaking, they fracture with a very regular smooth polished cleavage surface in at least one direction, and frequently they show two such regular cleavages. Chemically, the feldspars fall into two quite distinct subgroups; the orthoclase or potash feldspars and the plagioclase or soda-lime feldspars. The former group contains only two mineral species orthoclase and microdine which differ only in optical charac- ters. The plagioclase group is more complex, containing a long series of feldspars ranging in composition from albite (a soda feldspar) at the one extreme to anorthite (a lime feldspar) at the other. The intermediate stages in this series have been given distinct names, but may probably be regarded simply as mixtures of albite and anorthite molecules in various proportions. In the following table the composition and specific gravity of the various feldspars are recorded. Orthoclase is placed first, after which the various plagioclase feldspars follow in the order of their decrease in silica content. The orthoclase and plagioclase feldspars differ little in appear- ance, so that it is difficult to distinguish them except under the microscope or by analysis. This is unfortunate, for the distinc- 26 BUILDING STONES AND CLAYS tion between the two subgroups is often important, since they differ in geologic associations as well as in composition. Ortho- clase is a common constituent of the more acid igneous rocks, such as the granites and syenites; while the common feldspar of basic rocks such as trap, gabbro and basalt is invariably a plagio- clase feldspar. TABLE 4. COMPOSITION AND SPECIFIC GRAVITY OF THE FELDSPARS. Name. Specific gravity. Formula. Silica. Alu- mina. Potash. Soda. Lime. Orthoclase . . . Albite 2.57 2 62 K 2 O, A1 2 O 3 , 6 SiO 2 Na 2 O A1 2 O 3 6SiO 2 64.60 68 62 18.50 19 56 16.90 11 82 Oligoclase . 2 64 63 70 23 95 1 20 8 11 2 05 Andesine 2.65 Labradorite 2.69 52 90 30 30 4 50 12 30 Bytownite . . Anorthite . . . 2.71 2.75 '2CaO,Al 2 b 3 ,'4SiO2 43.08 36.82 20.10 One point which often aids in the separation of the two groups may be noted. The cleavage faces of orthoclase are perfectly smooth, while close examination of the cleavage faces of a plagio- clase feldspar will often show that they are crossed by a series of close-set parallel lines. Color and association also aid some- what in the distinction. Orthoclase is usually white, pinkish, red or very light grayish in color; and is frequently associated with quartz. A white plagioclase feldspar, in a rock which also contains considerable quartz and orthoclase, is probably albite. On the other hand, a bluish or dark gray plagioclase feldspar, in a rock containing little or no quartz or orthoclase, is labradorite or another of the more basic plagioclases. (3) The micas occur in glistening scales or flakes, usually white, yellowish dark brown, or black in color. They include two common species muscovite and biotite and several species of less importance. Mica, the familiar " isinglass" of stove doors, is readily scratched by a knife, and even more readily split into thin leaves or flakes along its cleavage planes. The light-colored micas can not be mistaken for any other common mineral in igneous rocks. The dark micas, however, might be confused with hornblende or augite, since both show the same dark-colored smooth glistening surfaces ; but the splitting proper- ties of the mica are not shared by hornblende or augite. IGNEOUS ROCKS IN GENERAL 27 Though a number of species of mica are recognized, only two are sufficiently common as rock-forming minerals to require consideration here. The two common species are, as above noted, muscovite and biotite. Of these, muscovite is a light- colored mica, occurring frequently in granites, schists and the more acid gneisses; but very rarely in the gabbros, basalts and similar basic rocks. Biotite, on the other hand, occurs very commonly in certain basic rocks; and somewhat less frequently than muscovite in the more acid types. Fairly representative analyses of specimens of these micas are given below: TABLE 5. ANALYSES OF MICAS. Muscovite. Biotite. Silica 46.3 40.0 Alumina . 36.8 17.28 Ferric oxide 4.5 0.72 Ferrous oxide 4.88 JMasrnesia 23 91 Potash 9.2 8.57 Comparison of these analyses will show that muscovite is relatively high in alumina, while biotite contains large per- centages of magnesia and ferrous oxide. This results in charac- teristic differences in weathering, for while muscovite is little affected by atmospheric action, the oxidation of the ferrous iron in the biotite makes it assume a more or less rusty appearance on long exposure. Muscovite is slightly lower in specific gravity - 2.6 to 3.0, as compared with the 2.8 to 3.2 of biotite. (4) The amphibole-pyroxene group includes a large number of species, two of which are of common occurrence in igneous rocks. These are hornblende (amphibole) and augite (pyroxene), which are not readily distinguished from each other in the hand speci- men. Both are commonly green to almost black in color, and usually break with one smooth fracture surface; but are dis- tinguishable from the dark micas, which they often resemble in appearance, in not being readily split into thin leaves or plates. Though non-aluminous amphiboles and pyroxenes occur, the hornblende and augite which are the common rock-forming 28 BUILDING STONES AND CLAYS varieties are essentially silicates of alumina, lime, magnesia and iron. The following analysis is fairly representative. Silica 48.8 Alumina 7.5 Ferrous oxide 18.2 Lime 10.2 Magnesia 13.6 Hornblende occurs more frequently in diorites and granites, while augite is characteristic of the more basic rocks. Slight differences of specific gravity are to be noted, that of hornblende ranging commonly from 3.15 to 3.33, while that of augite varies from 3.3 to 3.55. (5) Olivine or peridot is a silicate of iron and magnesia occurring as an essential constituent of the ultra-basic igneous rocks; and as a common constituent of all the basic rocks. It usually occurs in small glassy grains, varying in color from yellowish green to olive green. The grains are brittle, and usually will show one smooth cleavage or fracture surface. One of the more important relations of olivine to the stone industry arises from the fact that some of the serpentines dis- cussed in Chapter V have originated through the alteration of rocks rich in olivine. Certain other minerals are apt to be developed as secondary products, in case the rock has undergone alteration or more or less complete decomposition. The more important of these secondary minerals are calcite, magnesite, kaolinite, chlorite and serpentine. It is to be noted that, of this group, kaolinite is the only species likely to result from the alteration of the acid igneous rocks; the other four secondary minerals being more commonly associated with the decomposition of basic rocks. The Classification of Igneous Rocks. The classification of the massive igneous rocks, as at present practiced by professional petrographers, has attained a degree of precision and refinement which renders it entirely useless to the engineer or quarryman. The systematic classification now adopted by most American petrographers is based upon chemical analyses of a grade un- attainable in ordinary laboratory practice, interpreted and sup- plemented by means of the microscope. In the hands of a specialist such chemical and optical data can be combined to IGNEOUS ROCKS IN GENERAL 29 give results of great exactness, but by others than specialists they can not be safely applied, and the classification * based upon them is of no economic importance. For our present purposes, the following grouping will be found sufficiently accurate and precise. A. Rocks which are entirely crystallized, so that each of the constituent minerals is recognizable. 1. Granites: composed essentially of quartz and feldspar; with usually lesser amounts of mica, or hornblende, or both. The feldspar is occasionally all orthoclase; but commonly some plagioclase is also present. The mica may be either muscovite, or biotite, or both. 2. Syenites: composed essentially of feldspar, with sub- ordinate amounts of mica or hornblende. Quartz is entirely or practically lacking. The feldspar is usually a mixture of orthoclase and plagioclase. 3. Diorites: composed essentially of hornblende and felds- par, the former being in excess. Mica, usually biotite, may be present in considerable quantity. Quartz is rare or absent. The feldspar is commonly a plagio- clase, though orthoclase may also be present in sub- ordinate amounts. 4. Gabbros: composed essentially of pyroxene and feldspar, the former being in excess. Olivine may be present, as well as biotite. The feldspar is usually one of the more basic plagioclases. 5. Hornblendites : composed essentially of hornblende, felds- par being absent. Pyroxene and olivine may be pres- ent in subordinate amounts. 6. Pyroxenites: composed essentially of pyroxene, feldspar being absent. Hornblende and olivine may be present in subordinate amounts. * The reader desirous of further enlightenment regarding this classification may, at his own risk, read the papers noted below: Cross, W., and others. A quantitative chemico-mineralogfcal classifica- tion and nomenclature of igneous rocks. Journal of Geology, vol. X., pp. 555-690, 1902. Washington, H. S. Chemical analyses of igneous rocks published from 1884 to 1900, with a critical discussion of the character and use of analyses. Professional Paper, No. 14, U. S. Geol. Survey, 495 pp., 1903. 30 BUILDING STONES AND CLAYS 7. Peridotites: composed essentially of olivine (peridot), feldspar being absent. Pyroxene and hornblende may be present in subordinate amounts. B. Rocks in which the bulk of the rock forms a dense fine- grained, unrecognizable groundmass, through which a few rela- tively large mineral crystals are scattered. These rocks are the porphyries. They may be further subdivided into quartz- porphyry, feldspar-porphyry, etc., according to the particular mineral which makes up the visible crystals. C. Rocks in which no mineral constituents are recognizable, the rock being a dense, fine-grained mass of microscopic crystals often with minor amounts of glassy matter. Subdivided on the basis of color and composition into : 1. Felsites; light colored, acid rocks. 2. Basalts; dark colored, basic rocks. D. Rocks which show no trace of crystallization, being glassy throughout. The volcanic glasses, which require no further consideration here. Since any of the above types of igneous rock may have been subjected, during or after cooling, to pressure sufficient to cause banding, we may find types of gneisses corresponding in com- position to any of the groups of massive rocks. A rock consisting of quartz, feldspar and mica, arrayed in quite definite layers, would be a granite-gneiss; a similarly laminated rock consisting chiefly of pyroxene and feldspar would be a gabbro-gneiss; and so on. Commercial Classification of Igneous Rocks. The scientific classification of the various igneous rocks is a matter of great complexity, as has been noted above. Fortunately or unfortu- nately, engineers and quarrymen have adopted a very simple working classification, recognizing only the following groups: (1) Granites: including the lighter colored, less dense, coarser grained igneous rocks, usually containing much quartz. (2) Traps: including the dark colored, dense, heavy igneous rocks, composed mostly of pyroxene, basic feldspars, etc., with little or no quartz. To these should be added a third class, usually derived from basic igneous rocks by weathering and other alteration processes. IGNEOUS ROCKS IN GENERAL 31 (3) Serpentines: including a series of (usually green) soft rocks, composed mostly of hydrated magnesium silicates. Pumice, lava, and other igneous products which have cooled rapidly at the earth's surface require no special comment here, being usually unfit for structural purposes and therefore of little importance to the engineer. It may be noted, however, that the natural puzzolan materials often used as cements (pozzuolana, trass, santorin, etc.) are all volcanic ashes. The distinction thus made by the trade between "granite" and " trap/' though not in complete accord with scientific group- ing, has certain underlying principles of commercial usefulness. The dark-colored basic rocks called "traps" agree in being tough and difficult to quarry and dress, of dark and somber colors, and rather susceptible to weathering; while the light- colored acid "granites" are more readily excavated and cut, usually of light and pleasing colors, and more resistant to atmos- pheric agencies. The serpentines differ from both of these classes in their fairly uniform greenish colors and in their softness. The relation between the scientific and the commercial classi- fications of rocks is about as follows (compare page 29, et. seq.). Under the head of granite the quarry man includes all the true granites and syenites, aficKhe^ coarser-grained varieties of diorite and-gabbro, though the last of these is rarely used for structural purposes. The trade name trap, on the other hand, includes the basalts, the peridotites, pyroxenites and hornblendites, and tha4mer-grained varieties of diorite and gabbro, though most^ . ^. commercial trap is -either basalt or a fine-grained gabbro. ^""TPhe other/ rocks listed in the scientific grouping felsite, porphyry and/ the volcanic glasses are rarely used in structural work. The serpentines, though usually derived from igneous rocks, find no place in the scientific classification above presented be- cause they are not original but secondary products. , CHAPTER III. GRANITES AND OTHER ACID ROCKS. Scope of the Term Granite. The term granite, as used in the stone industry, and as it will be employed usually in the present chapter, includes practically all of the igneous rocks except the traps and serpentines. This is a negative and appar- ently very loose definition, but as a matter of fact the term can be defined much more closely without seriously interfering with its trade application. |j By far the majority of the " granites" known to the stone trade are light-colored, coarse-grained stones, composed largely of quartz and feldspar, with usually some mica, occasionally hornblende acH-are}y-~ftttgite: (| The commercial granite, there- fore, is almost always a rock of the type which the geologist would also include in his more restricted use of the term granite. Occasionally, however, we find syenites and the coarser-grained gabbros and diorites handled under the trade name of " granite," but though these exceptions require note, it must be borne in mind that they are exceptions. In 99 cases out of 100, the granite of the stone trade is also the granite of the geologist. In certain parts of the country, however, the term granite is misapplied to kinds of rock which have no possible claim to it. This is often the case in districts where igneous rocks are scarce or entirely wanting; and in such districts sandstone and even limestone may be found, in certain local markets, under the local trade name "granite." Such a misapplication of the term has nothing to excuse it, from any point of view, and the most reasonable way to treat it is as an attempt to cheat the pur- chaser. The trade distinctions between the different kinds of granites are based largely upon differences in color, coarseness of grain and mineral constituents; for most of the technical properties and commercial values of granites depend on these three factors. 32 GRANITES AND OTHER ACID ROCKS 33 ORIGIN AND MODE OF OCCURRENCE. Origin of Granites. All of the rocks here grouped as granites are of course igneous in origin. More particularly, their general coarseness of crystallization and entire lack of any uncrystalline or glassy groundmass indicates that they did not reach the sur- face of the earth at the time when they cooled and solidified from their original state of fusion. If they had so emerged, they would have been subjected to very rapid cooling; and experience with slags shows that fused rock which cools quickly will take the form either of porous lava-like products or of dense close- grained (or glassy) masses. If, then, the granites had reached the earth's surface while still fused, the resultant quickness of cooling would not have permitted the component minerals to crystallize out completely in relatively large grains. It is therefore fair to assume that such coarse-grained rocks as the granites cooled while still some distance below the earth's surface; being protected or blanketed from rapid cooling by overlying beds of other rocks. It is true that in many areas granites now appear at the surface, but this is due to the fact that since their cooling and solidification the rock which then overlay them has been worn away and carried off, mostly by the action of surface waters. Mode of Occurrence. The chief commercial granites are found as portions of large igneous masses, which at the time of cooling were injected or intruded into other rocks. Through the processes of erosion, these igneous masses now appear at the earth's surface; and in many instances not only the covering rock but the rock which once surrounded them laterally has been removed. In these cases, the granite masses often project above the level of the surrounding country as a boss or dome-shaped hill. Many of the gneissoid granites which are quarried at various points in the eastern portion of the United States are taken from the ancient stratiform masses alluded to on page 18, as forming the bulk of the Archaean rocks. MINERAL CONSTITUTION OF GRANITES. Chief Constituent Minerals. Most commercial granites con- sist largely of feldspar and quartz, with commonly lesser amounts 34 BUILDING STONES AND CLAYS of mica or hornblende; and often with small percentages of other minerals, such as tourmaline, garnet, apatite, rutile, etc. In a few syenites which reach the market notably the Fourche Mountain granite of Arkansas, quartz is scarce or lacking; and in this particular Arkansas case the feldspar is replaced by the closely allied minerals elceolite and nepheline. Likewise, in a few States rather basic rocks are quarried and sold under the name of granite; and in these cases augite is often present, while the feldspar is one of the plagioclases. In most commercial granites, however, the predominant min- eral is feldspar. At times this is orthoclase alone, but commonly some plagioclase feldspar is also present in lesser quantity. Next to the feldspar in abundance is quartz. Mica either muscovite or biotite, and frequently both is the third most common constituent; while hornblende occurs less frequently. Identification of Constituents. When the minerals in a granite are in grains or crystals sufficiently large to be clearly distinguished, the different essential minerals can usually be identified by use of the following key; which simply embodies in comparative form certain facts noted on previous pages (see pages 25-28). A. Showing at least one smooth cleavage surface. I. Separable into thin leaves; readily scratched by knife. a. Color white, often stained yellow. Mica (Mus- covite) . 6. Color black or brown. Mica (Biotite). II. Not separable into thin leaves. a. Color light usually whitish, gray, pink or light green. Feldspar. 6. Color dark green to greenish black. Hornblende or Augite. B. No smooth surface apparent; fracture rough and glassy; not scratched by knife; color usually light gray to light blue, translucent. Quartz. Relative Proportions of Minerals. Considerable industrial as well as scientific interest attaches to a study of the relative pro- portions in which the various constituent minerals occur in any given granite. There are three ways of determining this. As the three methods differ in ease and in accuracy they will be briefly discussed. They are: GRANITES AND OTHER ACID ROCKS 35 1. Direct Weighing. In this method the sample is coarsely crushed; the different constituent minerals are separated by means of heavy solutions; and the respective proportions are determined by actual weight. This is the most exact and most tedious of the methods. 2. Chemical Deduction. In this method the mineral com- position is calculated from the chemical analysis of the sample. The analysis must be of high grade; and errors are necessarily introduced because of certain assumptions which must be made as to the composition of the standard minerals. This method is the second in rank, so far as difficulty is concerned; and under ordinary conditions probably gives the least accurate results of the three. 3. Surface Measurement. In this method the surface areas of the various minerals, as exposed either on a microscope slide or on a polished surface, are measured; and the relative pro- portions of the various constituents are calculated from these, surface measurements. This is the easiest of the methods, and ranks second in accuracy. Color of Granites. Most granites of commercial importance are light to dark gray, or reddish in color, though occasionally granites of other colors are marketed. Granites ^with bluish tints, usually faint, are, for example, seen in certain areas, and a few distinctly greenish granites are on the market. One granite, used in part for an important structure, is quite distinctly yellowish in tint. But these exceptions only serve to emphasize the fact that by far the majority of granites used in any large way are either gray or red. When the dark minerals biotite, hornblende and augite are not present in great quantity, the color of a granite is determined largely by the color of the feldspar which it contains. There is some slight reason for preferring gray or light red granites to others, on the ground of durability, for they are generally composed of minerals which are more resistant to weathering. While granites should be carefully examined to see that the feldspar is fresh and translucent, for a chalky effect is often produced by incipient decay of that mineral. Good yellow granites are extremely rare, for that tint is usually due to the formation of rust through decay of mica (biotite) or some other iron-bearing minerals. Black or greenish granites are apt; 36 BUILDING STONES AND CLAYS to contain large percentages of minerals that are relatively non- resistant to weathering such as bkrtite, mica, hornblende, augite, the more basic feldspars, etc. TABLE 6. MINERAL COMPOSITION OF AMERICAN GRANITES. (T. N. Dale.) State. Locality. Quartz. Ortho Plagio- clase. clase. Micas. Horn- blende. Maine Massachusetts .... Jonesport Milford Quincy 44.65 35.66 30.60 8.43 28.85 22.45 55.91 60.02 69.51 4.05 8.43 9.37 22.06 .... 33.50 33.74 23 01 56.00 58.79 67.37 10.50 7.47 9.62 .... Rockport 33.10 35.82 31.95 38 90 55.80 57.97 58.45 55 50 11.10 6.20 9.60 5.60 New Hampshire . . Vermont Becket Milford u n u Conway Redstone u Madison Hardwick 33.88 34.70 49.35 27.09 36.76 27.40 17,. 10 31.04 28.65 38.26 28.60 21.75 58.86 59.60 28.55 15.37 29.72 34.03 27.58 29.16 29.28 27.70 31.30 45.22 63.15 65.30 54.79 67.20 62.05 'e'.57 8.58 6.50 13.51 5.74 5.81 5.55 6.95 4.20 16.20 7.26 5.70 Newark 30.30 64.80 4.64 Randolph Barre Woodbury 21.20 26.58 29.15 76.50 65.52 64.35 2.30 7.90 6.48 (i 31.22 27.10 63.11 65.60 5.67 7.30 Rhode Island tt Rochester Westerly 29.60 36.09 25.28 62.10 28.44 30.63 20.29 44.48 8.30 4.09 7.43 ti n 29.87 35.40 28.35 6.74 In many cases, however, the selection of stone for a structure rests with the architect, not with the engineer, and this occa- sionally brings about surprising results. In one instance which came to attention an architect of repute paid special prices to obtain what seemed to him a particularly desirable grade of GRANITES AND OTHER ACID ROCKS 37 * < '.'.*_ stone. He had selected this variety because of its soft yellowish tint, and apparently did not realize that it was simply the weath- ered phase of a bluish granite, and owed its soft colors to a pretty thorough decay of its feldspar. Such a case is of course excep- tional, but the desire for a satisfactory color effect should never be allowed to conflict with the necessity for obtaining a sound stone. STRUCTURE AND TEXTURE OF GRANITES. Granites are made up of closely interlocking crystals of various minerals. These crystals may differ greatly in size; they may show fairly definite banding or may be entirely without any orderly arrangement. The granite, considered as a rock mass, may present certain phenomena as to obvious or incipient frac- ture planes. All of these features require consideration under the present heading. Coarseness of Crystallization. Granites vary widely in coarseness of crystallization, from fine-grained rocks in which the individual crystals of quartz and feldspar may be one- fiftieth of an inch or even less in average diameter, up to coarse aggregates in which the quartz and feldspar may average an inch or more in diameter. The size of grain has an important bearing on the value of the stone for various uses. This effect may be briefly summarized as follows: 1. For monumental work, or where a high polish is desirable, the finest-grained stone is most suitable. 2. For structural work, the medium-grained stones are best adapted. 3. Coarse-grained stone can be used for little except crushed stone. 4. Very coarse-grained stones the pegmatites may, as later noted, furnish supplies of quartz and feldspar for the pottery and other industries. Laminated or Gneissoid Structure. The term gneiss is applied to rocks which have the same chemical and mineralogical composition as the granites and their allies, and which from their associations and occurrence are usually known to be of igneous origin; but in which the constituent minerals are arranged in roughly parallel layers or bands. 38 BUILDING STONES AND CLAYS In a granite, or any other normal igneous rock, the various mineral constituents are scattered through the rock without showing any trace of systematic arrangement; and this lack of arrangement is exactly what would be expected to result when a large mass of fused rock cools down without disturbance from external forces. In places, however, we find rocks of undoubtedly granitic composition and origin, but differing from normal granites in that they show a more or less laminated or Fig. 14. Lamination and joint planes in gneiss. (Photo by E. C. Eckel.) banded structure (Fig. 14). On examination, this is seen to be due to the fact that the constituent minerals (quartz, feldspar, mica, etc.) of these banded or gneissoid granites are arranged in roughly parallel layers. Since these rocks are undoubtedly igneous in origin, this lamination can not have originated in the same way as the beds and layers seen in sedimentary rocks, though the final result is much the same so far as appearance goes. Some further explanation is therefore required as to the origin of this gneissoid structure. It has been said that the laminated appearance is due to the GRANITES AND OTHER ACID ROCKS 39 fact that the minerals are arranged in parallel layers. This parallelism, in its simplest form, is carried only to the stage that the longer axes of the various mineral crystals are so arranged as to lie in the same plane. In more extreme cases, there has been also some degree of segregation of the different mineral constituents, so that a layer of quartz, practically free from mica or feldspar, will lie next to a layer of mica or feldspar containing practically no quartz. All of this rearrangement of the minerals, whether it be of the simpler or of the more complex type, must have originated through the action of external stresses on the granite mass, either during its slow cooling from fusion or at a later date. If the latter, it is obvious that almost complete refusion of the rock must have occurred, in order that the gneissoid structure could be produced. It may be noted here that few granites, even those which show absolutely no trace of lamination when viewed in the mass, have escaped entirely from the effects of strain, either external or internal, occurring during or after their cooling. This is evi- denced by the phenomena of rift and grain, referred to in later paragraphs. Sheet Structure. In many regions it is noted that granite masses show a more or less irregular division, or tendency to division, into sheets roughly parallel to the exposed surface of the mass (Fig. 15). This sheeting has been ascribed to the effects of temperature changes on the exposed surfaces; and in many cases this explanation is doubtless sufficient. At times, however, evidence is found that similar structures are developed at considerable depths below the surface, and the obvious in- adequacy of surface temperatures as causes of deep structural changes has led various geologists to ascribe some or all sheeting structure to strains induced during the original cooling of the mass, or to the effects of later external stresses. Rift and Grain. Granite, not being a stratified rock, of course does not possess the bedding planes which practically all of the stratified rocks exhibit, and along which they usually split most readily. The laminated granites or gneisses, it is true, split easily in the planes of their lamination which thus have the same structural effect as the bedding planes of sedi- mentary rocks. 40 BUILDING STONES AND CLAYS Even the most massive granites, however, such as show no trace of lamination or gneissoid structure to the eye, are found by the quarryman and stone dresser to break and cut more readily in certain directions than in others. There are com- monly two such planes of relatively easy fracture, usually at about right angles to each other. The quarryman speaks of the planes of easiest fracture as the rift, and of the other plane as the grain. Fig. 15. Sheet structure in granite. (Photo by E. C. Eckel.) The fact that an apparently massive rock does possess such planes of relatively easy fracture seems to depend upon the existence of minute microscopic fractures crossing the rock in the direction of the planes, or in the direction of one of them. These microscopic fractures, which are practically incipient planes of cleavage, may in some cases be due to internal stresses set up during the original cooling of the granite; but in most cases they are probably due to the effect of earth movement on the rock after its cooling. GRANITES AND OTHER ACID ROCKS 41 For more detailed discussion of these phenomena reference may be made to the papers by Dale and others cited below.* Value of Microscopic Work on Granites. The examination of a thin section of a granite under the petrographic microscope should result in identifying accurately the component minerals of the stone, and in affording some estimate as to their relative abundance. So far the results are of merely scientific interest, and if microscopic work could produce no further information it might be dispensed with altogether. Fortunately, however, it occasionally affords results which justify its use in the study of a structural granite. The data which under favorable circumstances may be ob- tained by the aid of the microscope relate to the physical con- dition of the component minerals, and of the rock itself. In- cipient decay of the feldspars, partial rusting of the iron-bearing minerals and the existence of minute cleavage planes in the rock may be noted by the investigator. All of these data are of a class which possesses economic as well as theoretical interest. CHEMICAL COMPOSITION OF GRANITES. Value of Chemical Work on Granites. The strength of a granite is not directly related to its chemical composition, so that chemical analysis is of no practical importance in deter- mining the possible strength of the stone. It will, however, throw a little light on its other physical properties for example, the denser granites are usually those lowest in silica but even then it will be found quicker and less expensive to make specific gravity determinations directly rather than to attempt to infer their results from a chemical analysis. So far as durability is concerned the case for chemical work is but little stronger, though here also we might draw some rather hazardous conclusions, such, for example, as that the rocks lowest in silica will probably prove less durable than rocks of more acid type. * Dale, T. N. Rift and grain (in granites). Bull. 313, U. S. Geol. Survey, pp. 26-29, 1907. Also Bull. 354, U. S. G. S., pp. 19-22. 1908. Tarr, R. S. The phenomena of rifting in granite. Amer. Journal Science, 3d series, vol. 41, pp. 267-272. 1891. Whittle, C. L. Rifting and grain in granite. Engineering and Mining Journal, vol. 70, p. 161, 1900. 42 BUILDING STONES AND CLAYS From the purely engineering point of view, therefore, there is but little reason for making a chemical analysis of a granite. If the analysis be a really good one, however, it will be of service in assigning the stone to its proper place in the geological classi- fication. On the other hand, analyses as made and reported by an ordinary laboratory will be of little use to any one or for any purpose. Normal Chemical Composition of Granite. The term granite, as used in the stone trade, is construed so broadly that at first sight it might seem impossible to say anything definite concern- ing the average or normal chemical composition of granite. This has, at any rate, been the attitude taken by most of the writers on this subject. As a matter of fact, however, a study of the subject will soon prove that the difficulty is more imaginary than real; and that it is due chiefly to a failure to realize that the occurrence of a few abnormal types does not seriously disturb the average result. It is probably safe to say that there is really not much more variation in the composition of commercial granite than there is in the composition of a number of samples of commercial Port- land cement. That is to say, if we could sample all of the granite sold in any given year, the range in either direction from the average would not be much greater than in a similar series of cement samples. The extent of this range in granite composition is well illus- trated in the series of tables of granite analyses (Tables 8 to 24). In those tables it is accentuated because of the inclusion of a number of gneisses, syenites, etc. These are marketed as granites, and their analyses are presented for completeness, but it must not be forgotten that the total quantity of such stone sold is unimportant in comparison with the quantity of normal granite. The following table contains a number of average analyses. The Georgia average is taken from a report by T. L. Watson; all of the other averages were prepared by the present writer. The final average in the last column is merely the arithmetical average of the preceding seven columns a method of treat- ment which is accurate enough for our present purposes. GRANITES AND OTHER ACID ROCKS 43 TABLE 7. AVERAGE COMPOSITION OF GRANITES. State Maine. Massa- chu- setts. New Jersey. Vir- ginia. South Caro- lina. Georgia. Wiscon- sin. Final average. Number of analyses averaged. ! 7 10 10 6 15 21 7 76 Silica Alumina 73.02 14.89 75.65 13.30 73.75 13.91 70.79 14.04 69.67 15.24 69.67 16.63 73.72 13.38 72.42 14.48 Ferric oxide 0.83 1.41 1.06 1.90 1.79 1.28 1.60 1.41 Ferrous oxide 0.86 0.70 1.23 1.32 2.48 1.02 1.09 Lime . 1.02 0.88 1.27 2.03 1.81 2.13 1.62 1.54 Magnesia 0.13 0.06 0.41 0.76 0.66 0.55 0.41 0.43 Potash 5.20 4.81 4.51 4.43 4.46 4.71 3.63 4.54 Soda 3.44 4.10 3.43 3.63 3.64 4.73 3.17 3.73 Water 0.46 0.34 0.27 0.41 0.45 0.43 0.34 From the averages in the above table it will be seen that all the striking individual variations are eliminated as soon as even a small group of analyses are averaged. The final average in the last column may be accepted as a fair statement of the normal composition around which granites range. Composition of American Granites. The following tables con- tain analyses of representative American granites, arranged by states. TABLE 8. ANALYSES OF GRANITES: MAINE. 2 3 4 5 6 7 Aver- age. Silica 73.02 74.64 71 54 73.48 74 54 70 94 72 97 73 019 Alumina 16.22 14.90 14.24 15.26 13.30 15.68 14.63 14.890 Ferric oxide Ferrous oxide Lime 2.59 0.94 1.56 0'39 0.74 1.18 0.98 1.42 0.88 0.92 0.79 1 26 2.29 1 23 i!73 1 48 0.83 0.857 1 023 Magnesia Potash tr 3.42 tr 6.88 0.34 4.73 0.09 5.66 0.01 5.01 0.19 5 54 0.27 5 18 0.131 5.203 Soda 3 60 41 3 39 3 12 3 69 3 58 3 28 3 439 Water 0.61 0.55 0.37 0.33 0.465 1. Blue Hill, Hancock County; Ricketts & Banks, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 393. 2. Blue Hill, Hancock County; H. J. Williams, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 393. 44 BUILDING STONES AND CLAYS 3. North Jay, Franklin County; E. T. Rogers, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 392. 4. Waldsboro, Lincoln County; Ricketts & Banks, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 391. 5. High Isle, Knox County; J. F. Kemp, analyst; Bull. 313, U. S. G. S., p. 122. 6. Hurricane Island, Knox County; Ricketts & Banks, analyst; Bull. 313, U. S. G. S., p. 137. 7. Jonesboro, Washington County; Ricketts & Banks, analyst; Bull. 313, U. S. G. S., p. 170. TABLE 9. ANALYSES OF GRANITES: MASSACHUSETTS. l 2 3 4 5 6 7 8 9 10 Aver- age. Silica Alumina . . Ferric ox. . Ferrous ox 76.07 12.67 2.00 76.95 11.15 0.25 0.55 tr. tr. 5.03 5.60 0.20 69.46 17.50 2.30 81.05 14.70 2.71 77.08 12.54 0.95 72.07 14.43 1.25 0.89 1.18 tr. 5.41 5.85 0.35 75.77 13.59 1.14 0.52 0.94 tr. n.d. n.d. 0.49 76.52 12.21 "2". 66 0.79 0.13 4.68 2.86 0.41 73.93 12.29 2.91 1.55 0.31 0.04 4.63 4.66 0.41 77.61 11.94 0.55 0.87 0.31 tr. 4.98 3.80 0.23 75.651 13.302 1.406 0.704 0.881 0.064 4.813 4.100 0.335 Lime Magnesia . Potash . . . Soda 0.85 0.10 4.71 3.37 2.57 0.31 4.07 3.01 0.82 1.10 tr. n.d. n.d. 0.44 0.75 0.01 4.99 3.64 Water 1. Milford, Worcester County; C. F. Chandler, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 404. 2. Milford, Worcester County; H. P. Talbott, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 403. 3. Chester, Hampden County; J. F. Kemp, analyst; 18th Ann. Rep. U. S. G. S., pt. 5, p. 965. 4. Cape Ann, Essex County; Watertown Arsenal, analyst; 20th Ann. Rep. U. S. G. S., pt. 6, p. 402. 5. Milford, Worcester County; L. P. Kinnicutt, analyst; Min. Res. U. S., 1903, pamphlet ed., p. 119. 6. Milford, Worcester County; R. H. Richards, analyst; Min. Res. U. S., 1903, pamphlet ed., p. 119. 7. Milford, Worcester County; R. H. Richards, analyst; Min. Res. U. S., 1903, pamphlet ed., p. 119. 8. Milford, Worcester County; R. C. Sweetzer, analyst; Bull. 354, U. S. Geol. Surv., p. 88. 9. Quincy, Mass.; H. S. Washington, analyst; Bull. 354, U. S. Geol. Surv., p. 93. 10. Rockport, Mass.; H. S. Washington, analyst; Bull. 354, U. S. Geol. Surv., p. 123 GRANITES AND OTHER ACID ROCKS 45 TABLE 10. ANALYSES OF GRANITES: NEW HAMPSHIRE. 1 2 3 4 5 6 Silica 73.15 72.47 71.44 70.42 66.80 74.47 Alumina ) Ferric oxide ? 17.04 16.17 14.72 2.39 14.64 1.54 18.29 14.15 1.16 Ferrous oxide ; Lime . 81 0.41 1.65 0.46 tr. 2.34 tr. 5.35 1.70 1.21 1 70 Magnesia Potash 0.30 5 74 0.14 4 83 0.96 89 1.20 71 i 77 0.63 4 14 Soda 2 05 3 43 7 66 7 80 6 09 1 97 Water. 26 1. Troy, Cheshire County; L. P. Kinnicutt, analyst; 20th Ann. Rep. U. S. Geol. Surv., pt. 6, p. 418. 2. Mason, Hillsboro County; Ricketts & Banks, analysts; 20th Ann. Rep. U. S. Geol. Surv,,, pt. 6, p. 418. 3. Redstone, Carroll County; F. C. Robinson, analyst; 20th Ann. Rep. U. S. Geol. Surv., pt. 6, p. 417. 4. Redstone, Carroll County; F. C. Robinson, analyst; 20th Ann. Rep. U. S. Geol. Surv., pt. 6, p. 417. 5. Lancaster, Coos County; E. R. Angell, analyst; Min. Res. U. S., 1903, pamphlet ed., p. 136. 6. Concord; Sherman & Edwards, analysts; Bull. 354, U. S. G. S., p. 150. TABLE 11. ANALYSES OF GRANITES: CONNECTICUT. 2 3 4 Silica (SiO 2 ) 68 40 72 73 72 06 68 11 Alumina (AlgOs) 15 75 ) 14 83 14 28 Ferric oxide (Fe2Os) 2 97 16 95 1 28 ) Ferrous oxide (FeO) . . 65 ) 64 f 2.63 Lime (CaO) ... 1 64 1 05 1 20 1 86 Magnesia (MgO) Potash (K 2 O) 0.12 5 78 tr. 8 15 0.13 5 64 0.68 5 46 Soda (Na 2 O) 4.16 90 4 31 6 57 Water above 100 C. ) 48 22 65 n d Water below 100 C. } ' 1. Millstone Point, H. T. Vulte, analyst. 2. Red granite Co., quarry, Stony Creek, L. P. Kinnicutt, analyst. 3. Brooklyn Quarry, Stony Creek, H. T. Vulte, analyst. 4. Booth Bros, quarry, Waterford; Ricketts & Banks, analysts; 20th Ann. Rep. U. S. G. S., pt. 6., p. 364. Bulletin Geol. Soc. America, vol. 10, p. 375. 46 BUILDING STONES AND CLAYS TABLE 12. ANALYSES OF GRANITES: VERMONT. i 2 3 Silica 69.56 77.52 69.89 Alumina 15.38 16.78 15.08 Ferric oxide 2 65 84 1 04 Ferrous oxide 1.46 Lime 1.76 2.56 2 07 Magnesia . tr. 0.32 0.66 Potash 4.31 0.62 4.29 Soda 5.38 1.21 4.73 Water 1.02 0.33 54 1. Barre, Washington County; W. C. Day, 20th Ann. Rep. U. S. Geol. Surv., pt. 6, p. 445. 2. Bethel, Windsor County; C. S. McKenna; Min. Res. U. S., 1903, p. 177. 3. Barre, G. I. Finlay, Rept. Vt. State Geol. for 1902, p. 55. TABLE 13. ANALYSES OF GRANITES: RHODE ISLAND. i 2 3 Silica (SiO) . 71.23 71.64 73.05 Alumina (AJ2O3) 13.65 15.66 14.53 Titanic oxide (FejOs) 0.21 Ferric oxide (F^Og) 1.70 ) Ferrous oxide (FeO) . . . 1.00 J 2.34 2.96 Manganous oxide (MnO) 0.05 tr. tr. Lime (CaO) 2.31 2.70 2.06 Magnesia (MgO) 0.75 tr. tr. Potash (K 2 O) 3.79 5.60 5.39 Soda (Na 2 O) 3.55 1 58 1.72 Water above 100 C. ) Water below 100 C. (' ' 1.72 0.48 0.29 1 . Conanicut Island, L. V. Pirsson, analyst. Bulletin Geol. Soc. America, GRANITES AND OTHER ACID ROCKS 47 TABLE 14. ANALYSES OF GRANITES: NEW YORK, PENN- SYLVANIA, AND DELAWARE. Constituent. 1 2 3 4 5 Silica Alumina 63.19 10.50 66.72 16.15 69.10 14.69 74.84 18.90 67.98 15.14 Ferric oxide 10.97 ) j 4.63 3.69 1 Ferrous oxide 1.51 [ .42 ) n.d. \ .oy Lime 6.12 2.30 1.90 1.54 5.89 IVIagnesia 1.44 0.73 0.68 0.92 0.53 Potash 4.02 5.66 ) ( 0.45 9.00 Soda . . . 1 .92 4.36 ( ( 4.32 Water 0.19 0.77 0.30 1. Hornblende diorite. lona Island, N. Y. J. F. Geiste, analyst. 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 421. 2. Augite syenite. Little Falls, Herkimer County, N. Y. E. W. Morley, analyst. 3. Hadley, Saratoga County, N. Y. Pittsburg Testing Laboratory, analyst. Min. Res. U. S. for 1903. 4. Ridley Park, Chester County, Pa. Solvay Company, analyst. Min. Res. U. S. for 1903. 5. Augustine, Newcastle County, Delaware. Booth, Garrett & Blair, analyst. Min. Res. U. S. for 1903. TABLE 15. ANALYSES OF GRANITES: NEW JERSEY. 1 2 3 4 5 6 7 8 9 10 Aver- age. Silica (SiO 2 ) . 71.91 77.59 74.36 75.56 69.48 75.02 75.15 74.70 68.60 75.17 73.754 Alumina (M 2 Z \. . . . 15.71 10.53 12.75 12.61 16.42 13.73 14.65 15.45 14.72 12.55 13.912 Ferric oxide (Fe 2 O 3 ) ... 0.21 0.21 2.09 0.64 0.56 0.83 0.11 0.08 4.29 1.54 1.056 Ferrous oxide (FeO) 0.13 1.74 1.35 1.16 2.60 0.99 0.90 0.64 1.41 1.41 1.233 Lime (CaO) . 0.70 0.76 0.82 0.84 3.45 0.88 0.92 1.70 1.46 1.15 1.268 Magnesia (MgO) 0.03 1.01 0.11 0.05 1.15 0.03 0.04 0.06 0.38 0.21 0.407 Potash (K 2 O) 8.60 5.30 3.76 5.93 1.18 4.74 4.71 2.62 3.52 4.62 4.506 Soda (Na 2 O) . 2.61 1.58 3.44 2.35 4.59 3.36 3.60 4.90 4.82 3.07 3.432 Water (H 2 O). 0.27 0.60 0.20 0.42 0.34 0.17 0.24 0.10 0.16 0.22 0.272 Analyses 1-10 by R. B. Gage. Quoted from An. Rep. State Geologist, N. J., for 1908. 1. Coarse grained pink granite, Pompton Junction. 2. Gneiss inclusions in preceding granite. 3. Gray gneissoid granite, di Laura's quarry, near Haskell. 4. Pinkish granite-gneiss, Charlotteburgh. 48 BUILDING STONES AND CLAYS 5. Dark gray granite, Malley's quarry, Morris Plains. 6. Reddish granite-gneiss, Allen quarry, Waterloo. 7. Whitish granite-gneiss, quarry two miles north of Waterloo. 8. White granite-gneiss, D. L. & W. R. R. quarry south of Cranberry Lake. 9. Gray granite, Kice's quarry, north of German Valley. 10. Light gray gneiss, Kice's quarry, west of German Valley. TABLE 16. ANALYSES OF GRANITES: MARYLAND. 1 2 3 4 5 6 7 Silica 74.87 72.57 71.79 71.45 70.45 66.68 62.91 Alumina 14.27 15 11 15 00 14 36 15 98 14 93 19 13 Ferric oxide . . . 0.59 0.77 2.07 0.75 1 58 98 Ferrous oxide ... 0.51 1.02 1.12 2.78 1.84 3.32 3 30 Lime 0.48 1.65 2.50 1.58 2.60 4.89 4.28 Magnesia 0.16 0.30 0.51 1.17 0.77 2.19 1.69 Potash 5 36 4 33 4 75 3 28 3 59 2 05 3 38 Soda 3 06 3 92 3 09 1 95 3 83 2.65 3 94 Water . 0.92 0.47 0.64 1.30 0.45 1.25 0.63 All of the above analyses are by W. F. Hillebrand, and are quoted from 15th An. Rep. U. S. Geol. Survey, page 672. The localities were as follows: 1. White granite, Brookville, Montgomery County. 2. Biotite-muscovite granite, Guilford, Howard County. 3. Biotite granite, Woodstock, Baltimore County. 4. Biotite granite, Sykesville, Carroll County. 5. Biotite granite, Dorsey Run Cut, Howard County. 6. Biotite granite, Rowlandsville, Cecil County. 7. Biotite granite, Dorsey Run Cut, Howard County. TABLE 17. ANALYSES OF GNEISSES: MARYLAND AND DISTRICT OF COLUMBIA. i 2 3 4 5 Silica 73.69 69.33 67.22 63.43 78.28 Alumina . . 12.89 14.33 15.34 16.69 9.96 Ferric oxide 1.02 2.78 3.36 1.85 Ferrous oxide Lime 2.59 3.74 3.60 3.21 3.41 1.36 3.87 0.80 1.78 1.68 IMagnesia 0.50 2.44 1.65 2.33 0.95 Potash . 1.48 2.67 3.26 3.22 1.35 Soda 2.81 2.70 2.00 2.38 2.73 Water 1.06 1.22 1.97 2.90 0.95 1. Biotite gneiss, Port Deposit, Cecil County, Md. Wm. Bromwell, analyst. 20th Ann. Rep. U. S. Geol. Surv., pt. 6, p. 399. 2. Biotite gneiss, Broad Branch quarry, District of Columbia. W. F. Hillebrand, analyst; 15th An. Rep. U. S. Geol. Surv., p. 672. GRANITES AND OTHER ACID ROCKS 49 3. Potomac Stone Company quarry, below Chain Bridge, D. C. Ibid, p. 670. 4. Emery's Store, Cabin John Bridge, Montgomery County, Md. Ibid, p. 670. 5. Great Falls, Montgomery County, Md. Ibid, p. 670. TABLE 18. ANALYSES OF GRANITES: VIRGINIA. 1 2 3 4 5 6 7 8 9 10 Average of 1-8. Silica 72.27 71.51 71.19 70.83 69.48 69.44 69.29 68.45 60.52 58.32 70.787 Alumina . . 14.30 13.82 14.01 12.70 13.95 15.46 14.07 10.00 16.99 15.77 14.04 Ferric ox. 1.16 1.76 1.66 2.67 2.82 1.31 2.59 5.71 0.60 6.56 1.897 Ferrous ox. 0.97 1.20 1.29 1.36 1.70 1.43 2.03 2.59 6.53 0.59 1.325 Lime 1.56 1.79 2.04 1.88 2.81 2.11 2.67 6.20 4.58 11.58 2.032 Magnesia .' 0.70 0.80 0.14 0.53 1.10 1.01 1.32 3.26 1.59 0.09 0.763 Potash . . . 5.00 4.63 4.45 4.83 3.45 4.25 2.87 1.18 3.91 4.01 4.435 Soda . . . 3.45 3.64 3.56 3.49 3 65 3 97 2.89 1.98 2.83 0.32 3.628 Water .... 0.29 0.48 0.37 0.41 0.54 0.36 0.43 0.80 0.88 1.73 0.408 All the above analyses are quoted from Bulletin 426, U. S. Geol. Survey, pages 72 and 78. Analyses 1 to 8 inclusive are by M. W. Thornton; analyses 9 and 10 by W. C. Phalen. The localities are as follows: 1. Biotite granite, Westham quarries, Richmond, Chesterfield County. 2. Biotite granite, Petersburg Granite Co., Petersburg, Dinwiddie County. 3. Biotite granite, McGowan quarry, Chesterfield County. 4. Biotite granite, Netherwood quarry, Chesterfield County. 5. Biotite granite, Cartwright and Davis quarries, Fredericksburg, Spottsylvania County. 7. Biotite gneiss, Middendorf quarry, Manchester, Chesterfield County. 8. Biotite gneiss, Cartwright and Davis quarries, Fredericksburg, Spott- sylvania County. 9. Pyroxene syenite, Milams Gap, Page County. 10. Epidote granite, Milams Gap, Page County. TABLE 19. ANALYSES OF GRANITES: NORTH CAROLINA. 1 2 3 4 5 6 Silica 75.92 75.14 71.56 70.70- 69.28 66.01 Alumina 14.47 n.d. 16.79 n.d. 17.44 n.d. Ferric oxide 88 n.d. 1 87 n.d. 1 08 n.d. Ferrous oxide n.d. n.d. 1 22 n.d. Lime ... 02 0.93 2.93 2 96 2 30 1 44 Magnesia 0.09 n.d. 0.30 n.d. 27 n.d. Potash 4.01 2.57 ) ( 2.45 2.76 3.16 Soda Water 4.98 0.64 5.82 j n.d. 11.96 n.d. H.56 n.d. 3.64 n.d. 5.06 n.d. 50 BUILDING STONES AND CLAYS 1. Quartz porphyry; Charlotte, Mecklenburg County; Genth, analyst; Geology of North Carolina, Vol. 1, p. 124. 2. Pink Granite Company, quarry, Dunn's Mt., Rowan County, Bull. 426, U. S. Geol. Surv., p. 117. 3. Granite; Mount Airy, Surry County; C. M. Cresson, analyst; 18th An. Rep. U. S. Geol. Surv., pt. 5, p. 970. 4. Granite; Mount Airy, Surry County; Bull. 426, U. S. Geol. Surv., p. 117. 5. Granite; Raleigh, Wake County; Hanna, analyst; Geology of North Carolina, vol. 1, p. 302. 6. Granite; Johnson quarry, Mooresville, Iredell County; Bull. 426, U. S. G. S., p. 117. TABLE 20. ANALYSES OF GRANITES: SOUTH CAROLINA. * 2 3 4 5 6 7 8 9 10 Silica 68.70 68.71 68 8f 68.90 59 52 69 74 70 11 70 2C 70 54 70 77 Alumina 15.49 15.41 15 7? 15.75 16.77 13.72 15 76 14 22 14 56 14 89 Ferric oxide . . 1.10 1.85 2.14 1.16 0.95 ( 3AA ( 1.07 1.14 1.06 0.75 Ferrous oxide . 3.73 1.59 1.57 1.49 1.56) .04 ) 1.76 1.24 1.62 1.24 Lime 1.70 1.64 1.64 2.66 1.82 1.54 1.84 2.14 1.28 2.08 Magnesia 0.86 1.25 i.ie 0.74 0.75 0.22 0.62 0.48 0.78 0.43 Potash 3 36 4 61 4 5^ 1: 3 '49 4 10 4 98 4 27 4 82 5 37 4 70 Soda. . . 3 09 3 48 3 4 4 76 3 43 5 39 3 3 C 5 3S 3 97 4 47 Water 0.81 0.34 0.32 . 0.18 1.43 0.45 0.33 0.27 0.19 11 12 13 14 15 16 17 18 19 Aver- age. Silica 70.90 71.20 72.19 72.22 73.26 62.34 65.72 58.15 73.10 70.384 Alumina. . 15.25 17.04 14.06 14.51 15.39 17.22 17.22 14.30 13.82 15.237 Ferric ox. Ferrous ox. 1.52 I 1.53 f 3.48 j 0.70 I 1.80 1.28) 1.52$ 1.24 j 1.75 12.49 1.70 2.67 2.44 2.49 0.93 1.43 1.795 2.477 Lime 2.40 n.d. 1.88 1.32 1.36 3.28 2.80 2.80 1.72 1.807 Magnesia. 0.63 0.11 0.84 0.58 0.38 1.30 1.45 1.04 0.51 0.655 Potash . . 2.85 4.70 3.94 4.30 6.89 5.14 3.80 3.84 5.06 4.461 Soda 4.32 2.32 3.46 3.21 0.55 5.28 3.68 3.80 3.04 3.645 Water .... 0.17 0.63 0.18 0.52 n.d. 0.28 0.35 0.28 0.23 0.448 All of the above analyses are quoted from Bulletin 426, U. S. Geol. Survey, pages 174-175. The localities are as follows: 1. Porphyritic biotite granite, Clouds Creek, near Batesburg, Saluda County. 2. Porphyritic biotite granite, Flat Rock, Kershaw County. 3. Biotite granite, Cold Point Station, Laurens County. 4. Biotite granite, Jackson quarry, Clover, York County. 5. Biotite granite, Leitzsey quarry, Newberry, Newberry County. 6. Biotite granite, Anderson quarry, Rion, Fairfield County. 7. Biotite granite, Excelsior quarry, Heath Springs, Lancaster County. GRANITES AND OTHER ACID ROCKS 51 8. Biotite granite, Flatrock quarry, Carlisle, Union County. 9. Biotite granite, Benjamin quarry, Greenwood, Greenwood County. 10. Muscovite-biotite granite, Whiteside quarry, Filbert, York County. 11. Muscovite-biotite granite, Blair, Fairfield County. 12. Biotite granite, Keystone Granite Company, Pacolet, Spartanburg County. 13. Biotite granite, Ross quarry, Columbia, Lexington County. 14. Biotite granite, Southern Granite Company, Heath Springs, Kershaw County. 15. Biotite granite, Winnsboro Granite Company, Rion, Fairfield County. 16. Biotite gneiss, Hanckel quarry, Pendleton, Anderson County. 17. Biotite gneiss, Ware Shoals, Laurens and Abbeville Counties. 18. Biotite gneiss, Beverly, Pickens County. 19. Biotite gneiss, Bates quarry, Batesburg, Lexington County. TABLE 21. ANALYSES OF GRANITES: GEORGIA. ' 2 3 4 5 6 7 8 9 10 Silica 72.56 14.81 0.94 1.19 0.20 5.30 4.94 0.70 71.00 16.33 1.12 1.83 0.35 4.65 4.80 0.87 70.38 16.47 1.17 1.72 0.31 5.62 4.98 0.31 70.30 16.17 1.19 2.61 0.31 4.88 4.72 0.63 70.18 17.30 1.20 2.03 0.64 4.77 4.36 0.35 70.03 15.62 1.31 2.45 0.52 5.42 4.22 0.77 69.88 16.42 1.96 1.78 0.36 5.63 4.45 0.39 69.74 16.72 1.45 1.93 0.36 5.33 4.84 0.47 69.64 17.21 1.32 2.14 0.66 4.95 4.53 0.35 69.55 16.72 0.99 1.69 0.27 3.94 5.88 0.27 Alumina Ferric oxide Lime Magnesia Potash Soda Water 11 12 13 14 15 16 17 18 19 20 Silica Alumina Ferric oxide Lime Magnesia Potash Soda Water.... 69.53 16.46 1.15 2.10 0.85 4.91 5.00 0.91 69.45 15.93 1.31 1.91 0.55 5.16 4.33 0.50 69.36 17.23 1.43 2.14 0.59 4.57 5.17 0.33 69.34 17.01 1.74 2.77 0.61 4.54 4.69 0.26 69.25 16.04 1.72 1.89 0.31 4.94 4.52 0.43 69.08 17.67 1.41 3.27 0.64 3.29 4.56 0.56 69.07 16.56 1.37 1.83 0.76 5.02 4.65 0.92 68.81 17.67 1.13 2.17 0.50 3.90 4.97 0.30 68.79 16.48 0.98 1.76 1.30 5.85 4.74 0.38 68.76 16.80 0.99 2.72 1.00 3.70 4.82 0.29 21 22 23 24 25 26 27 28 29 30 Silica Alumina 68.38 17.79 1.21 2.85 0.72 3.57 4.36 0.78 66.92 18.19 3.05 4.95 1.25 2.02 3.83 0.46 63.27 19.93 2.82 2.89 0.49 4.85 4.14 0.86 70.90 15.86 1.37 2.15 0.02 4.62 5.05 0.50 70.88 15.86 1.77 1.79 0.93 4.64 3.94 0.49 70.24 16.78 1.46 2.00 0.76 5.03 3.70 0.50 69.77 17.05 1.60 2.21 0.99 4.08 3.97 0.44 69.48 16.64 1.84 2.32 0.29 4.49 4.74 0.46 69.37 16.99 1.99 2.03 0.84 4.54 3.44 0.55 69.17 16.47 1.22 2.02 0.61 4.41 4.89 1.06 Ferric oxide Lime Magnesia Potash Soda Water BUILDING STONES AND CLAYS TABLE 21 (Continued) 31 32 33 34 35 36 37 38 39 40 Silica 69.13 17.14 1.52 1.85 0.79 5.49 4.06 0.52 67.62 16.29 2.31 2.37 0.78 4.58 5.42 0.32 66.31 18.27 2.51 2.91 1.22 4.09 3.69 0.61 63.65 20.46 2.20 3.38 1.50 4.58 4.75 0.42 76.37 13.31 1.21 1.13 0.10 3.68 4.02 0.20 76.00 13.11 0.92 1.06 0.27 4.69 3.88 0.31 75.89 14.02 0.71 0.70 0.12 5.56 3.64 0.28 75.45 13.71 0.92 0.94 0.18 4.30 3.87 0.40 75.16 13.74 0.91 0.91 0.17 5.05 3.76 0.32 74.96 13.71 0.90 1.02 0.24 4.79 4.68 0.44 Alumina Ferric oxide Lime Magnesia Potash Soda Water 41 42 43 44 45 46 Silica 74.80 15.46 1.04 0.82 0.11 2.52 4.80 0.31 73.95 14.23 1.29 1.07 0.23 5.29 4.61 0.25 72.96 14.70 1.28 1.28 0.07 4.73 4.18 0.23 71.20 15.46 1.17 1.36 0.38 5.30 4.96 0.52 69.51 16.32 2.38 1.84 1.28 3.47 3.82 1.11 68.89 16.47 2.34 1.63 0.40 4.15 4.38 0.32 Alumina Ferric oxide Lime Magnesia Potash . . ... Soda Water Analyses 1 to 46 of the preceding table are quoted from Watson's report on the granites of Georgia, published as Bulletin 9, Georgia Geological Survey. All were made by T. L. Watson, on samples collected by himself. Nos. 1 to 23 inclusive are of normal granites; Nos. 24 to 34 are of porphyritic granites; and Nos. 35 to 46 of gneisses. The localities from which the various samples were taken are as follows: 1. Stone Mountain, DeKalb County. 2. Fortson quarry, near Goss, Elbert County. 3. Coggins Granite Company, near Elberton, Elbert County. 4. Diamond Blue Granite Company, Hutchins, Oglethorpe County. 5. Brown-Dead wyler quarry, in Madison County. 6. Lexington Blue Granite Company quarry, Oglethorpe County. 7. Greenville Granite County quarry, Meriwether County. 8. 9. Coggins Granite Company quarry, near Oglesby, Elbert County. 10. Carmichael quarry, Fairburn, Campbell County. 11. Hutchins, Oglethorpe County. 12. Swift & Wilcox quarry, Elberton, Elbert County. 13. Childs quarry, Oglesby, Elbert County. 14. Linch quarry, Eatonton, Putnam County. 15. Tate & Oliver quarry, Elberton, Elbert County. 16. Cole quarry, Newman, Coweta County. 17. Overby quarry, Coweta County. 18. Echols Mill, Oglethorpe County. 19. Hill quarry, Newman, Coweta County. 20. Turner quarry, Griffin, Spalding County. GRANITES AND OTHER ACID ROCKS 53 21. Camak, Warren County. 22. Grantville, Coweta County. 23. Tigner quarry, Odessa, Meri wether County. 24. Georgia Quincy Granite Company quarry, Sparta, Hancock County. 25. Lime Creek, Fayette County. 26. Flat Rock, Pike County. 27. Heggie Rock, Columbia County. 28. Sparta quarry, Hancock County. 29. Milledgeville, Baldwin County. 30. Moseley quarry, East Point, Fulton County. 31. Greensboro, Greene County. 32. Rocker quarry, Hancock County. 33. Brinkley property, Warren County. 34. McCollum quarry, Coweta, Coweta County. 35. Odessa quarry, Meriwether County. 36. Crossley quarry, Lithonia, Dekalb County. 37. Snell quarry, Snellville, Gwinnett County. 38. Tilley quarry, Rockdale County. 39. Arabia Mountain, Lithonia, Dekalb County. 40. Flat Rock, near Franklin, Heard County. 41. Flat Shoals, Meriweather Co. 42. Flat Rock, Coweta County. 43. Southern Granite Company quarry, Lithonia, Dekalb County. 44. Freeman quarry, Covington, Newton County. 45. Athens, Clarke County. 46. McElvaney Shoals, Gwinnett County. TABLE 22. ANALYSES OF GRANITES: ARKANSAS, MISSOURI AND OKLAHOMA. Constituent. l 2 3 4 5 6 7 8 9 Silica 60.03 20.76 4.01 0.75 59.62 18.67 5.07 59.70 18.85 4.85 72.35 13.78 1.87 0.36 0.87 0.42 4.49 4.44 0.76 71.88 12.88 3.05 1.05 1.13 0.33 4.46 4.21 0.43 71.33 12.55 3.75 0.85 0.94 0.58 4.20 4.52 0.42 69.94 15.19 1.88 0.60 1.15 0.92 4.29 3.95 0.99 77.05 11.77 2.33 n.d. 2.21 n.d. 3.88 2.90 0.52 65.30 19.94 2.60 4L50 1.00 J4.37 0.30 Alumina Ferric oxide Ferrous oxide Lime 2.62 0.80 5.48 5.96 1.80 0.84 5.65 6.95 0.80 1.34 0.68 5.97 6.29 1.88 Magnesia Potash . . Soda . . .... Water 1. Elaeolite syenite, Fourche Mt., Ark.; R. N. Brackett, analyst; An. Rep. Ark. Geol. Sur. for 1890, vol. 2, p. 39. 2. Elaeolite syenite, Bauxite Station, Ark.; W. A. Noyes, analyst; An. Rep. Ark. Geol. Sur. for 1890, vol. 2, p. 135. 3. Elaeolite syenite, Fourche Mt., Ark.; W. A. Noyes, analyst; An. Rep. Ark. Geol. Sur. for 1890, vol. 2, p. 181 54 BUILDING STONES AND CLAYS 4. Granite, Ironton, Mo.; W. Melville, analyst; Prof. Paper, No. 14, U. S. Geol. Sur., p. 147. 5, 6. Quartz porphyry, Ironton, Mo.; W. Melville, analyst; Ibid. 7. Granite, Ironton, Mo.; Ibid, p. 161. 8. Granite, Graniteville, Mo.; W. Melville, analyst; 18th An. Rep. U. S. Geol. Sur., pt. 5, p. 968. 9. Tishomingo, Oklahoma; Min. Resources U. S., for 1903. TABLE 23. ANALYSES OF GRANITE: WISCONSIN. 1 2 3 4 5 6 7 Aver- age. Silica (SiO 2 ). 76.54 66.10 75.40 74.62 76.62 73 65 73 09 73 717 Alumina (A^Os) . . . Ferric oxide (Fe 2 O 3 ) Ferrous oxide 13.82 1.62 20.82 1.52 2.17 11.34 4.16 10.01 3.85 1.72 13.02 1.01 11.19 1.31 3.25 13.43 2.57 13.376 1.604 1.020 Lime 85 1 57 0.90 2 43 51 2 78 2 29 1 619 Magnesia 0.01 95 33 05 51 1 03 412 Potash 2.31 3.48 6.44 3.38 6.38 1.86 1 58 3 633 Soda Water 4.32 20 2.94 54 1.76 3.33 24 2.24 3.74 44 3.85 72 3.169 428 1. Wausau, W. W. Daniells, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 2. Athelstane, W. W. Daniells, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 3. Montello, F. G. Weichmann, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 4. Waushara, S. Weidman, analyst; Bull. 4, Wis. Geol. Surv., p. 420. 5. Waushara, Milwaukee Monument Company, A. S. Mitchell, analyst; Min. Res. U. S., 1903, p. 204. 6. Berlin, S. Weidman, analyst; Bull. 4, Wis. Geol. Surv., p. 420. 7. Uttley, S. Weidman, analyst; Bull. 4, Wis. Geol. Sur., p. 420. TABLE 24. ANALYSES OF GRANITE: WESTERN AND PACIFIC STATES. Constituent. 1 2 3 4 5 6 7 8 9 Silica 75.35 61.47 58.67 68.50 71.78 68.24 71.70 71.98 67.45 Alumina 13.69 23.02 14.89 17.02 14.75 16.30 14.54 15.07 13.04 Ferric oxide ) Ferrous oxide ) ' 3.94 4.46 7.56J 3.25 i!94 1.37 2.13 1.46 1.80 1.97 0.82 5.56 2.78 Lime 2.97 5.59 5.68 4.66 2.36 3.20 3.13 2.46 4.68 Magnesia 0.06 trace 1.79 1.58 0.71 1.88 0.39 0.58 2.65 Potash Soda 2.85 1 14 1.22 4 09 2.69 7 69 2.10 3.55 4.89 3.12 |e.3o 6.06 6.92 3.57 Water 0.57 0.52 0.24 0.92 0.20 0.27 / ' re 1. Exeter, Tulare County, Calif.; Watertown Arsenal, analyst; Min. Res. U. S., 1903. 2. Snake River, Nez Percys County, Idaho; W. C. Day, analyst; Min. Res. U. S., 1903. GRANITES AND OTHER ACID ROCKS 55 3. Reno, Washoe County, Nevada; J. W. Phillips, analyst; 20th An. Rep. U. S., pt. 6, p. 416. 4. Haines, Baker County, Oregon; Watertown Arsenal, analyst; Min. Res. U. S., 1903. 5. Little Cottonwood Canyon, Utah; T. M. Drown, analyst; Reports Fortieth Parallel Survey, vol. 2, p. 356. 6. Medical Lake, Washington; R. W. Thatcher, analyst; vol. 2, Reports Washington Geol. Sur., p. 141. 7. Snake River, Washington; ibid. 8. Little Spokane River, Washington; ibid. 9. Index, Washington; ibid. PHYSICAL PROPERTIES OF GRANITES. Density. Data regarding the specific gravity and weight per cubic foot of granites are available in sufficient quantity to serve as bases for general conclusions. With regard to absorp- tion and porosity this is not the case, for here the methods of testing differ so widely that no general comparisons can be made. TABLE 25. AVERAGE SPECIFIC GRAVITY OF GRANITES. AND WEIGHT Results averaged. Specific gravity. Weight per cubic foot, average. Minimum. Average. Maximum. 12 New England granites 2.618 2.645 2.629 2.644 2.677 2.655 2.671 2.739 2.713 17 Georgia granites 14 Wisconsin granites . . Final results, average 2.618 2.659 2.739 165.92 Compressive Strength of Granites. In a preceding section it was noted that the variations in chemical analyses of granites seemed, at first sight, to be so great as to defy any attempt to generalize concerning normal composition; but that careful ex- amination showed that the difficulty was not insurmountable. The same things can be said, with equal truth, regarding the compressive strength of granites. In the table (Table 27) presented later, the results of com- pression tests on seventy-five American granites are tabulated. These present wide variations, the lowest test reported in the table showing only 5657 pounds per square inch, while the 56 BUILDING STONES AND CLAYS highest result is 47,674 pounds. If we take the column of averages, however, it is soon found that these extreme results* do not fairly represent the situation. In the following table the tests are grouped into classes, according to average results. TABLE 26. AVERAGE COMPRESSIVE STRENGTH OF GRANITES. Class. Number of tests. Below 15,000 Ibs. per square inch 7 Between 15,000 and 20,000 Ibs 16 Between 20,000 and 25,000 Ibs 30 Between 25,000 and 30,000 Ibs 12 Over 30,000 Ibs. per square inch 10 Total tests 75 From this grouping it can be inferred that the average granite will fall within the third class of the above table. As a matter of fact, the arithmetical average of all of the seventy-five tests recorded in Table 27 is actually 23,228 pounds per square inch. * The low results are on schists and poor gneisses; the highest results are the remarkable tests reported by the Wisconsin Geological Survey. GRANITES AND OTHER ACID ROCKS 57 r- e ooo S 8 S 3 55 55 S S g S : "^.^ -3 ^^ I 5 II I .3 5 Wt =8 g ggg H " 5 I HJtfJ S -Ja *a +j O S 5 I 15^-s 00 a I IISIS Wford, Co ............. ia Granite Co., n, Middlesex Co. ia Granite Co., n, Middlesex Co. Island ............ oint ............. & Donohue, Augus astle Co ;| Md ; :'S :W : II w bi w ^-o-Sl^o^^ -S r 1 WJI i llrf iff!! 1 ^- >>S m m"" J^d : O : s;|||d^l| ** M -j*J:l i^lS|||| 58 BUILDING STONES AND CLAYS O> O l>- Oi O CO O5 < H C^ (M CT> CO OOO i J52 SS2" ^ CO O >0 i U3 >>>>.>> >>>>>>>>>>>>>>>> >, && >> 1111 11111111 1 22 1 >>>> >>>>>>>> > 333 53335533 '5 gtscoaccc c j H ^ 1 11 1 f | ^^^^r^^^^ ^ S <; >> H a '3'3 ' M | Dp {3 .3.5 60 BUILDING STONES AND CLAYS TABLE 28. TRANSVERSE STRENGTH OF GRANITES. 1 . 4 . I - State. Locality. Tested by 3 1 1 I a 1 M * < In. In. In. Arkansas Watertown 5 20 4 6 1067 1400 1755 California Exeter Watertown 20 4 6 1853 Georgia Stone Mt. . Watertown 20 6 6 2610 Maine Millbridge. Watertown "2" 20 4 6 2027 2048 2069 Massachusetts . Cape Ann . . Watertown 19 4 6 2392 Wisconsin. . Montello . . Buckley. . . 2 4 1 1 3678 3794 3910 it New Hill.. Buckley. . . 2 4 1 1 2324 2519 2713 TABLE 29. PHYSICAL PROPERTIES OF ENGLISH GRANITES (BEARE). Specific gravity. Weight. Absorb. Penrhyn 2.65 165 4 12 16,490 Cornwall 2.59 161.7 14,870 Aberdeenshire: Corennie 2 58 161 40 19 855 Cove 2 71 169 1 55 15 355 Kemnay 2 605 162 5 32 17 880 Craigton . 19 935 Peterhead 2.54 158.5 29 18,785 Dyce 2.65 165.4 0.19 17,200 Hill of Fare 2.55 159.1 0.40 21,160 Sclattie 2 58 161 10 13 230 Persley 2 60 162 3 19 14 665 Rubislaw 2.623 163.7 09 18 575 Ben Cruachan 2.75 171.6 0.29 13,640 Geological Distribution of Granites. Rocks of granitic type may have formed the greater proportion of the original crust of the earth, but it is improbable that any of these first-formed granites are now exposed at the surface. Granites and granitic gneisses, however, undoubtedly still make up the major portion of the pre-Cambrian rocks, so far as these rocks are now open to inspection. And in all of the geologic periods, from the pre- Cambrian to the Tertiary, masses of granite and allied rocks have been intruded into the existing formations. The result of this history is that, among the granites exposed at the surface to-day, almost every geologic age is represented in some part GRANITES AND OTHER ACID ROCKS 61 of the world. When looked at in this broad fashion, little definite can be said regarding the geologic age of granites; but when the inquiry is limited to smaller areas the question of age admits of discussion. The area which supplies by far the bulk of American commer- cial granites, for example, is that located in New England. The southward extension of the same area along the Blue Ridge and Appalachian regions promises to become of greater industrial importance yearly. In both of these areas, a relatively small portion of the granites and gneisses quarried are of pre-Cambrian age. The bulk of the commercial granites is derived from masses intruded into pre-Cambrian or later rocks during the Silurian, Devonian and Carboniferous periods; and it seems probable that most of these intrusive granites date back only to the Carboniferous. In the western states a greater range in geologic age is shown, and here no general statement of value can be made, owing to the relatively small development of the granite industry. Granites do not occur in Ohio, West Virginia, Tennessee, Indiana, Illinois, Florida, Mississippi, Louisiana, Kansas, Iowa, Nebraska and North Dakota; they occur at only one or two localities in South Dakota and Kentucky; and in small areas only in Missouri, Arkansas, Texas and Oklahoma. In the remaining states rocks of granitic type cover considerable areas. Production of Granite in the United States. The following tables, revised slightly from those published by the United States Geological Survey, give statistics concerning the granite industry for a series of years. It is to be noted, however, that in these tables trap and other basic igneous rocks are included under the general head of " granite " in most states. TABLE 30. GRANITE PRODUCTION OF THE UNITED STATES, 1899-1909. Year. Value. Year. Value. 1899 $10,343,298 1905 $17,563,139 1900 10,969,417 1906 18,562,806 1901 14,266,104 1907 18,064,708 1902 16,083,475 1908 18,420,080 1903 15,703,793 1909 19,581,597 1904 17,191,479 1910 20,541,967 62 BUILDING STONES AND CLAYS TABLE 31. GRANITE PRODUCTION, BY STATES, 1905-1909. State or Territory. 1905. 1906. 1907. 1908. 1909. Arizona $3,700 $32,042 $13,700 $8,544 (a) Arkansas 90,312 118,903 168,996 152,567 $150 179 California 1 161 330 ' 740 784 1 306 324 1 684 504 1 310 520 Colorado 73 802 65402 67 134 121 282 74 326 Connecticut Delaware . 636,364 178,428 974,024 146,346 591,153 158,192 592,904 195,761 610,514 456 328 Georgia 971,207 792,315 858,603 970,832 843,542 Hawaii 33,550 23,346 19,599 81,219 68,955 Idaho 1,500 400 25,942 (a) (a) Maine 2 713 795 2 560 021 2 146 420 2 027 508 1 939 524 Maryland Massachusetts . 957,048 2,251,319 883,881 3,327,416 1,183,753 2,328,777 762,442 2,027,463 771,224 2 164 619 Michigan Minnesota 481,908 626,069 546,603 629,427 i b 660,823 Missouri 180 579 150 009 136 405 157 968 155 717 Montana 126 430 114 005 102 050 (a)- (0) Nevada New Hampshire New Jersey 838,371 76,758 818,131 101,224 647,721 75,757 867,028 125,804 1,215,461 60,175 New Mexico 167 294 (a) New York 134,425 304,048 289,722 367,066 443,910 North Carolina .... Oklahoma Oregon . 564,578 20,720 85,330 778,847 18,847 58,961 889,976 24,550 117,625 764,272 23,239 271,869 743,876 67,584 284,135 Pennsylvania 450,619 349,453 366,679 324,241 507,814 Rhode Island 556,364 622,812 674,148 556,474 933,053 South Carolina South Dakota 297,284 247,998 129,377 690 297,874 (a) 218,045 Texas 132,193 168,061 122,158 190,055 173,271 Utah 13,630 4,948 5,240 5,229 7,525 Vermont 2,571,850 2,934,825 2,693,889 2,451,933 2,811,744 Virginia 452,390 340,900 398,426 321,530 488,250 Washington 681 730 459 975 562,352 870,944 742,878 Wisconsin Wyoming 825,625 798,213 600 1,228,863 90 1,529,781 (a) 1,442,305 Other States 40,320 c 235,300 Total 17,563,139 18,562,806 18,064,708 18,420,080 19,581,597 a Included in "Other States." b Includes a small value for trap rock in Michigan and Minnesota. c Includes Arizona, Idaho, Montana, and New Mexico. GRANITES AND OTHER ACID ROCKS 63 TABLE 32. GRANITE PRODUCTION OF 1909, BY STATES AND USES. State or Territory. Sold in the rough. Dressed for building Dressed for mon- umental work. Made into Kg. Building. Monu- mental. Rubble. Riprap. Other. Arkansas $1,000 30,536 15,267 25,097 9,769 39,685 3,100 237,597 120,561 212,075 43,659 4,093 143,757 7,366 35,399 56,859 1,471 6,996 306,466 45,501 67,877 29,530 996 128,233 24,965 11,478 300 2,502 $39,579 28,451 35,867 28,i74 $9,522 12,798 4,950 5,342 1,557 33,216 $68,000 109,847 18 112,830 280,488 59,245 $799 432,551 24,000 274,501 2,043 120,270 $120 97,978 66,538 2,693 $34,476 8,698 9,084 93,300 California $2,875 1,200 1,382 Colorado Connecticut Delaware Georgia Hawaii Maine 31,375 8,471 508,805 76,636 46,750 70,018 1,000 1,864 11,682 16,541 5,460 10,400 176,565 5,215 36,082 4,396 1,154,826 1,966 6,308 26,984 8,940 14,685 70,479 51,658 48,210 23,387 150 17,639 5,803 13,050 4,75i 1,510 19,680 14,090 6,695 2,462 1,093 3,878 4,367 200 5,421 34 8,000 53,637 22,141 4,166 1,386 18,408 26,271 4,450 17,752 1,152,677 114,002 542,441 144,997 5,930 521,299 1,133 17,193 142,778 15,408 2,321 53,529 218,089 1,000 36,612 1,035,675 17,750 17,185 5,154 22,000 39,704 2,675 298,235 167,088 2,300 192,762 50 23,903 38,192 5,691 16,129 ' 314,237 ii',400 2,133 479,415 9,449 19,902 212,043 3,000 262,895 93,742 308,203 66,605 46,163 170,434 2,250 250,070 214,508 37,348 15,840 52,004 4,284 5,824 18,053 66,544 982,798 Maryland Massachusetts Minnesota Missouri New Hampshire New Jersey 200 942 2,971 New York North Carolina Oklahoma Oregon i',950 73 1,755 2,875 '"166 Pennsylvania Rhode Island South Carolina Texas Utah . i',037 33,321 423,230 420 1,000 Vermont Virginia Washington Wisconsin - Other States Total 1,612,135 2,342,355 797,395 775,740 64,796 4,920,737 2,005,637 2,743,117 64 BUILDING STONES AND CLAYS TABLE 32. GRANITE PRODUCTION OF 1909, BY STATES AND USES. (Concluded.} State or Territory. Curbing. Flagging. Crushed stone. Other. Total. Road- making. Railroad ballast. Concrete. (a) $150,179 1,310,520 74,326 610,514 456,328 843,542 68,955 (a) 1,939,524 771,224 2,164,619 (6) c 660,823 155,717 (a) 1,215,461 60,175 (a) 443,910 743,876 67,584 284,135 507,814 933,053 218,045 173,271 7,525 2,811,744 488,250 742,878 1,442,305 235,300 Arkansas $300 163,012 '"$375" '"256" '"246" " 13,770 " 2,427 3,666 $68,338 262,077 '"7,834" 20,105 16,405 40,855 " 10,786" 138,465 56,805 $1,470 57,064 $630 65,020 "$2,338" 440 2,850 500 996 "52,756" 8,739 3,935 ""l',256" '"4,775" "i',923" " 17,31 1" 19 2,185 '"56" 4,400 14,381 45,460 13,569 California Connecticut Delaware 45,573 3,960 318,957 23,752 30,337 83,497 25,000 ""7,849" 158,468 36,344 98,485 46,864 '"336" 38,576 8,533 Georgia Hawaii Idaho Maine Maryland Massachusetts Michigan 74,739 3,474 113,705 Minnesota 8,154 150 40,221 15,345 "2l',429" 26,220 36,540 31,258 Missouri Montana New Hampshire New Jersey 53,088 635 "44,966" '"2,666" 28,151 "i',025 ' 5,625 2,617 15,827 9,360 2,124 " 33', 235" 101,866 3,500 5,480 39,004 17,125 32,834 947 New Mexico 52,263 44,617 '206,372" 41,047 99,358 10,672 32,584 New York 1,352 North Carolina Oklahoma 98,153 2,000 "'8,461' 5,955 3,554 1,100 1,233 ""3,664" 3,490 '"w" Oregon Pennsylvania Rhode Island South Carolina Texas Utah Vermont 1,319 29,100 76,574 3,048 15,100 '"996" " 16,875" 765 74,054 88,868 125,838 13,608 1,000 125,704 Virginia Washington Wisconsin 147,112 ' 155,581 23,385 Other States (<*) Total 1,030,568 47,230 1,488,711 660,632 914,667 177,877 19,581,597 o Included in " Other States." 6 A small value for trap rock included in Minnesota. c Includes a value of trap rock for Michigan and Minnesota. d " Other States " includes Arizona, Idaho, Montana, and New Mexico. GRANITES AND OTHER ACID ROCKS 65 TABLE 33. NUMBER AND VALUE OF GRANITE PAVING BLOCKS PRODUCED IN 1908 AND 1909, BY STATES AND TERRITORIES. State or Territory. Paving blocks. 1908. 1909. Number. Value. Number. Value. California 1,657,600 292,485 121,000 4,735,770 8,005,662 692,538 6,134,648 532,750 1,826,742 2,842,206 96,956 1,573,777 3,679,745 5,900 1,000,000 529,037 567,416 351,250 6,000 58,200 358,664 3,000 13,399,882 $66,079 14,951 6,050 135,510 368,715 71,316 261,880 35,750 75,320 103,833 2,674 98,273 122,488 400 40,000 23,628 29,651 12,277 300 1,547 10,173 255 939,485 817,500 180,130 187,095 3,384,600 6,137,682 1,107,149 6,878,872 974,000 1,150,914 4,997,161 30,000 3,571,997 5,062,500 $34,470 8,698 9,084 93,300 262,895 93,742 308,203 66,605 46,163 170,434 2,250 250,070 214,508 "37',348" 15,840 52,004 4,284 "5,824" 18,053 66,544 982,798 Connecticut Delaware Georgia Maine Maryland Massachusetts Minnesota Missouri New Hampshire New Jersey New York North Carolina Oklahoma Oregon 936,260 374,171 1,051,681 106,204 ' '163,885 853,300 1,109,072 18,798,977 Pennsylvania. . Rhode Island South Carolina Texas Vermont Virginia Washington Wisconsin Total 48,471,228 2,420,555 49.94 57,873,150 2,743,117 47.40 Average price per thousand .... 66 BUILDING STONES AND CLAYS TABLE 34. PRODUCTION OF GRANITE IN VERMONT IN 1908 AND 1909, BY COUNTIES AND USES. 1908. County. Number of firms re- porting. Building. Rough. Dressed. Quantity (cubic feet) . Value. Quantity (cubic feet). Value. Washington and Orange Windsor 39 3 9 3 15,896 63,537 12,753 12,050 $9,871 59,054 3,999 6,787 129,230 52,866 $429,967 244,850 Caledonia and Orleans Windham 1,225 1,250 Total 54 104,236 79,711 .76 173,321 676,067 3.90 Average price per cu. ft.. Monumental. Other - Paving. pur- Rough. Dressed. poses. County. Total Quantity (cubic feet). Value. Quan- tity (cubic Value. Quan- tity (num- ber of Value. Value. value. blocks). Washington and Orange Windsor 1,094,619 12,000 $1,015,006 6,000 164,706 $576,551 50,400 $1,262 $14,443 $2,047,100 309,904 Caledonia and Orleans . 117,560 66,580 1,000 5,666 2,175 77,754 Windham 11,750 7,637 200 500 7,800 285 716 17 175 Total 1,235,929 1,095,223 .89 165,906 582,051 3 51 58,200 1,547 17,334 2,451,933 Average price per cu. ft. GRANITES AND OTHER ACID ROCKS 67 TABLE 34. PRODUCTION OF GRANITE IN VERMONT IN 1908 AND 1909, BY COUNTIES AND USES (Concluded). 1909. County. Number of firms re- porting. Building. Rough. Dressed. Quantity (cubic feet). Value. Quantity (cubic feet). Value. Washington and Orange Windsor 34 3 10 3 3 44,020 111,020 45,000 12,950 750 $17,457 ) 88,816 ) 17,285 4,550 125 381,730 500 $1,034,575 500 Caledonia and Essex Windham Orleans Total Average price per cu. ft 53 213,740 128,233 .60 382,230 1,035,075 2.71 Monumental. Other Paving. pur- Rough. Dressed. poses. County. Total Quan- tity (cu- Value. Quan- tity (cu- Value. Quan- tity (num- Value. Value. value. bic feet). ber of blocks) Washington and Orange ) Windsor 1,210,696 $1,094,616 173,242 $478,349 29,885 $897 $8,161 { $2,297,910 424,961 Caledonia and Essex 94,962 44,789 62,574 Windham Orleans 233 37,943 233 15,188 100 400 250 816 134,000 4,927 110 100 10,070 16,229 Total Average price per cu. ft. . . 1,343,834 1,154,826 .86 173,742 479,415 2.76 163,885 5,824 8,371 2,811,744 68 BUILDING STONES AND CLAYS References on Granites. The following list contains the prin- cipal papers and reports dealing with granites and allied stones, chiefly from a commercial standpoint. For convenience of reference, the titles are arranged by states, in alphabetical order. Alabama: Watson, T. L. Granites of the southeastern Atlantic States. Bull. 426, U. S. Geol. Sur., 1910. Alabama granites on pp. 268, 269. Arkansas: Williams, J. F. The igneous rocks of Arkansas. Vol. II, Ann. Rep. Ark. Geol. Sur. for 1890, 457 pp. 1891. California: Anon. Granites of California. Bull. 38, Calif. State Mining Bureau, pp. 23-61. 1906. Connecticut: Dale, T. N. Granites of Connecticut. Bull. . . . , U. S. Geol. Sur. (in press, 1911). Georgia: Watson, T. L. Preliminary report on the granites of Georgia. Bull. 9, Georgia Geol. Sur., 367 pp. 1902. Watson, T. L. Granites of the southeastern United States. Bull. 426, U. S. Geol. Sur., 1910. Georgia granites on pp. 206-267. Maine: Dale, T. N. The granites of Maine. Bull. 313, U. S. Geol. Sur., 202pp. 1907. Maryland: Grimsley, G. P. The granites of Cecil County, in northeastern Maryland. Jour. Cinn. Soc. Nat. Hist., Vol. XVII, pp. 59-67, 78-114. 1894. Keyes, C. R. The origin and relations of Central Maryland granites. 15th Ann. Rep. U. S. Geol. Sur., pp. 685-740. 1895. Mathews, E. B. Granites and gneisses of Maryland. Vol. II, Rep. Md. Geol. Sur., pp. 136-169. 1898. Watson, T. L. Granites of the southeastern United States. Bull. 426, U. S. Geol. Sur., 1910. Maryland granites on pp. 39-69. Williams, G. H. Granitic rocks in the middle Atlantic piedmont plateau. 15th Ann. Rep. U. S. Geol. Sur., pp. 657-684. 1895. Massachusetts: Dale, T. N. The chief commercial granites of Massachusetts. Bull. 354, U. S. Geol. Sur., pp. 73-144. 1908. Minnesota: Winchell, N. H. The comparative strength of Minnesota and New England granites. 12th Ann. Rep. Minn. Geol. Sur., pp. 14-18. 1884. Missouri: Buehler, H. A. Granites and rhyolites of Missouri. Rep. Mo. Geol. Sur., 2d series, Vol. II, pp. 60-85. 1904. GRANITES AND OTHER ACID ROCKS 69 New Hampshire: Dale, T. N. The chief commercial granites of New Hampshire. Bull. 354, U. S. Geol. Sur., pp. 144-188. 1908. New Jersey: Lewis, J. V. Building stones of New Jersey. Ann. Rep. State Geologist N. J. for 1908. Granite, pp. 62-81. 1909. New York: Eckel, E. C. The quarry industry in southeastern New York. 20th Ann. Rep. N. Y. State Geologist, pp. 141-176. 1902. Smock, J. C. Building stones in the State of New York. Bull. 3, N. Y. State Museum, 152 pp. 1888. Smock, J. C. Building stone in New York. Bull. 10, N. Y. State Museum, 396 pp. 1890. North Carolina: Watson, T. L. Granites of the southeastern United States. Bull. 426, U. S. Geol. Sur., 1910. North Carolina, pp. 115-170. Rhode Island: Dale, T. N. The chief commercial granites of Rhode Island. Bull. 354, U. S. Geol. Sur., pp. 188-210. 1908. South Carolina: Watson, T. L. Granites of the southeastern United States. Bull. 426, U. S. Geol. Sur., 1910. South Carolina, pp. 172-205. South Dakota: Todd, J. E. The newly discovered rock at Sioux Falls, South Dakota. Am. Geologist, Vol. XXXIII, pp. 35-39. 1904. Texas: Burchard, E. F. Structural materials in the vicinity of Austin, Texas. Bull. 430, U. S. Geol. Sur., pp. 292-316. Vermont: Dale, T. N. The granites of Vermont. Bull. 404, U. S. Geol. Sur., 138 pp. 1909. Finlay, G. I. The granite area of Barre, Vermont. Rep. Vt. State Geologist for 1901-1902, pp. 46-59. 1902. Perkins, G. H. Report on the marble, slate, and granite industries of Vermont, 68 pp. Rutland, 1898. Perkins, G. H. Granite (in Vermont). Rep. Vt. State Geologist for 1899-1900, pp. 57-77. 1900. Virginia: Watson, T. L. Granites of the southeastern United States. Bull. 426, U. S. Geol. Sur., 1910. Virginia, pp. 70-115. Washington: Landes, H. The building and ornamental stones of Washington. Vol. II. Rep. Wash. Geol. Sur., 1903. Granites, pp. 32-47. Wisconsin: Buckley, E. R. Building and ornamental stones of Wisconsin. Bull. 4, Wis. Geol. Sur., 500 pp. 1898. CHAPTER IV. TRAP ROCK AND OTHER BASIC IGNEOUS STONES. Scope of Term. The term trap rock is applied commercially to a series of basic igneous rocks which usually agree in being dark-colored, dense and fine-grained. With few exceptions, the commercial trap rocks are geologically classified as either basalt, diabase or gabbro. Occasionally, however, some of the finer- grained, dark-colored diorites are marketed as trap. For convenience, so as to avoid too violent a separation of geologically allied rocks, all of the more basic rocks will be treated together in the present chapter. The groups thus covered in- clude the diorites, gabbros, diabase and basalt, and the still more basic peridotites, pyroxenites and hornblendites. Occurrence of Trap Rocks. The general modes of occurrence of igneous rocks have been discussed on pages 17-20 of this vol- ume, but in the present place it will be well to consider, in some- what greater detail, such phases of this matter as bear on the occurrence of trap rocks in particular. For our present purpose it is sufficiently exact to say that practically all of the basic igneous rocks which are of commercial importance will be found to occur in one of the following types of deposit: (1) In certain regions of pre-Cambrian rocks, both massive basic rocks and basic gneisses are found to cover considerable areas. Most of the traps of Wisconsin, Minnesota and Michigan are of this type; while many of the basic gneisses quarried in the eastern states are also from pre-Cambrian areas. (2) The bulk of the commercial trap rock, however, comes from deposits which are of more recent and more clearly recog- nizable origin. In Massachusetts, Connecticut, New York, New Jersey, Pennsylvania and Virginia the trap quarried is of Triassic age, and comes from intrusive sheets or surface flows. More rarely quarries of trap are established on dikes or in old volcanic necks. 70 TRAP ROCK AND OTHER BASIC IGNEOUS STONES 71 Color. Owing to their low silica content, and the prevalence of iron minerals, the basic igneous rocks are commonly dark colored. In the coarser-grained varieties of gabbro and diorite, the color effect may be mottled, the dark iron minerals being set off by feldspars which are lighter in tint, though in the basic rocks even the feldspars are commonly bluish or grayish. In the finer- grained diorites and gabbros, and in the basalts, diabases and ul- trabasic rocks the color is commonly almost uniform, and ranges from dark green or dark gray to almost black. Fig. 16. Columnar structure of trap. (Photo by N. H. Darton.) The above notes apply to the colors shown by these rocks when fresh. As all the basic rocks are susceptible to weathering, old outcrops usually show very different colors from that of the fresh rock. On such weathered surfaces any feldspar which the rock may contain is usually a dull chalky white; while the iron- bearing minerals have taken on yellowish, reddish or brown tints. Mineral Constitution. In none of the basic igneous rocks is quartz an important constituent ; and in most of them it is either entirely or practically lacking. The feldspar of the basic rocks is usually plagioclase, and not orthoclase. When a mica is 72 BUILDING STONES AND CLAYS present, it is commonly biotite, and not muscovite. All of the basic rocks contain either hornblende, pyroxene or olivine; and in some cases very large amounts of one or more of these very basic minerals. The proportions of the various minerals present in a number of specimens of diabase from New Jersey has been determined by Lewis with the results shown in the following table. For convenience of comparison, Lewis' results have been renumbered, so as to correspond with the numbers given to the chemical analyses of the same specimens in Table 38 on a later page. TABLE 35. MINERAL PROPORTIONS IN TRAP ROCKS. l 2 6 7 8 9 10 Quartz Per cent 19 Per cent 7 o o o Feldspar 44 42 20 38 37 QO 26 Augite 27 34 73 46 59 RQ 56 Biotite. . 3 o 1 1 o o 1 Olivine. . . o 4 13 1 5 16 Magnetite, etc 7 17 2 2 3 2 1 Identification of Constituents. Except in dealing with very coarse-grained types it will rarely be possible to identify the mineral constituents of a basic rock by merely examining it with the naked eye or even with a hand lens. In order to classify the rock correctly, either chemical analysis or microscopic investi- gation will be necessary, and frequently both will be required. Chemical Composition. The rocks included in this group are all characteristically low in silica, and relatively high in iron oxide, magnesia, lime and alkalies. The following tables (Tables 36-40) contain analyses of a representative series of commercial trap rocks from various producing localities in the United States. With these have been included a few analyses of basic rocks from localities which have not yet entered the producing list, but which may reasonably be expected to do so in the near future. TRAP ROCK AND OTHER BASIC IGNEOUS STONES 73 TABLE 36. ANALYSES OF TRAP: CONNECTICUT. i 2 3 4 '] Silica (SiO 2 ) 52.37 50.26 49.27 49.29 Alumina (Al 2 Oa) 15.06 15.16 15.87 15.97 Titanic oxide (TiO2) 21 Ferric oxide (Fe 2 Os) 2.34) j 1.93 1.88 Ferrous oxide (FeO) Manganous oxide (MnO) Lime (CaO) Magnesia (MgO) 9.82? 0.32 7.33 5.38 13.70 0.48 10.68 5.49 ) 10.17 0.35 7.46 5.90 10.23 0.40 7.42 6.07 Potash (K 2 O) 0.92 n.d. 0.71 0.69 Soda (Na 2 O) 4.04 n,d. 3.45 3.35 Carbon dioxide (CO 2 ) 1.12 1.17 Water above 100 C. ) 2.24 4.23 3.92 3.88 Water below 100 C. ) ' 1. Connecticut Trap Rock Quarries Company, Meriden; J. H. Pratt, analyst; 18th Ann. Rep. U. S. Geol. Sur., pt. 5. 2. Cooke Trap Rock Company, Plainville; H. Souther, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 365. 3. 4. Tidewater Trap Rock Company, East Haven; G. W. Hawes, analyst; Min. Res. U. S. for 1903. TABLE 37. TRAP: MASSACHUSETTS AND MINNESOTA. l 2 3 4 5 6 Silica 52.59 46.11 50.43 35.83 48 32 48 51 Alumina 23.42 17.20 23.83 ) 35 95 13 79 Ferric oxide 14 55 12 07 >48 45 ) Ferrous oxide 4.87 J17.63 1 19.34 Lime 9 05 10 96 4 79 9 35 12 05 8 34 Magnesia. 0.28 4 24 2 46 3 12 25 4 81 Potash 34 22 19 19 Soda 2 06 1 66 2 98 1 67 Water 3.06 1. Monson, Hampden County, Mass.; Watertown Arsenal, analysts; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 405. 2. West Roxbury, Suffolk County, Mass.; H. P. Williams, analyst; Min. Res. U. S. for 1903, pamphlet ed., p. 119. 3. Duluth, St. Louis County, Minn. Dodge. Vol. I, Rep. Minn. Geol. Sur., p. 198. 4. Taylor's Falls, Chicago County, Minn. Dodge. Vol. I, Rep. Minn. Geol. Sur., p. 198. 74 BUILDING STONES AND CLAYS 5. Beaver Bay, Lake County, Minn. Dodge. Vol. I, Rep. Minn. Geol. Sur., p. 198. 6. Tischer's Creek, St. Louis County, Minn. Dodge. Vol. I, Rep. Minn. Geol. Sur., p. 198. TABLE 38. ANALYSES OF TRAP ROCKS: NEW JERSEY.* 1 2 3 4 5 6 7 8 9 10 11 12 13 SiO 2 . . 60.05 51.34 53.13 51.88 50.40 52.48 49.62 51.141 51.03 49.02 46.78 51.46 50.34 A1 2 3 .. 11.88 12.71 13.75 14.53115. 60 14.98 10.51! 12.99 11.92 10.14 14.33 13.98 15.23 IS?'.: 3.22 10.21 2.65 14.14 1.07 9.10 1.35j 3.65 9.14 6.30 1.13 9.25 0.64 12.02 1.50 9.14 1.52 10.85 1.54 10.46 5.76 9.27 2.66 8.92 2.82 11.17 MgO.. 0.85 3.66 8.57 7.78 6.08 7.75 15.98 11.58 12.08 17.25 1.58 7.59 5.81 CaO.. 4.76 7.44 9.47 9.98 10.41 10.83 7.86 10.08 9.22 8.29 5.26 10.49 9.61 Na^O.. 4.04 2.43 2.30 2.06 2.57 1.87 1.40 1.72 1.50 1.59 3.43) 4*7K (2.93 K 2 O 2.10 1.44 1.04 0.93 0.62 0.43 0.55 0.52 0.39 0.40 1.75 j . la 11.02 HjO+. 0.66 0.69) OQA (0.97 1.67 0.23 0.49 0.59 0.54 0.59 0.10 0.07 H 2 O . 0.21 0.18( .VU 10.12 1.02 0.18 0.38 0.14 0.17 0.16 0.33 0.19 TiO 1.74 3.47 1.35 1.35 1.30 l.Oll 1.13 0.93 0.99 1.44 "i'.oe 1.56 s&; 0.52 0.28 0.20 0.36 '6! 44 0.14 0.10 0.16 0.06 0.13 0.27 0.16 0.09 0.06 0.16 0.08 0.15 0.11 0.16 0.36 0.25 0.17 0.20 0.14 100.52 100.71 99.77 100.33 99.89 100.83 100.71 100.75 100.38 100.70 100.64 101.08 101.09 Sp. gr. 2.872 3.089 2.96 2.98 2.89 3.110 3.118 3.051 3.122 3.152 2.968 14 15 16 17 18 19 20 21 22 SiO 2 ... A1 2 O. 50.19 14 65 51.09 14 23 51.77 14 59 51.82 14 18 51.84 15 11 51.36 16 25 49.68 14 02 49.17 13 80 49.71 13 66 aeE MgO 3.41 6.96 7 95 2.56 7.74 7 56 3.62 6.90 7 18 0.57 9.07 8 39 1.78 8.31 7 27 2.14 8.24 7 97 4.97 9.52 5 80 4.90 10.61 5 04 5.49 9.51 6 13 CaO NajO 9.33 2 64 10.35 1 92 7.79 3 92 8.60 2 79 10.47 1 87 10.27 1 54 v6.50 3 49 9.87 2 21 5.85 4 51 K 2 O H 2 0+ H 2 0- TiO 2 P 2 O 5 0.75 2.38 0.66 1.13 18 0.42 1.01 1.66 1.30 16 0.64 1.85 0.46 1.13 18 1.26 1.40 0.30 1.17 17 0.34 1.33 0.56 1.22 13 1.06 1.33 1.41 1.89 0.54 1.39 21 0.54 0.73 1.04 1.50 24 0.37 2.66 0.48 1.53 10 MnO 0.07 0.25 0.05 0.13 0.09 0.09 0.18 0.07 0.13 Sp. gr. 100.30 2 92 100.25 2 936 100.08 2 91 99.85 2 95 10.32 2 93 100.28 99.60 2.949 99.75 2.997 100.13 2.91 * Ann. Rep. N. J. State Geol. for 1907, pp. 120 et seq. contain analyses 1-22 of this table. 1. Quartz diabase, Penn. R. R. tunnel, Homestead; R. B. Gage, analyst. 2. Quartz diabase, Penn. R. R. cut, near Marion Station, Jersey City; R. B. Gage, analyst. 3. Diabase, Railroad cut, Jersey City; G. W. Hawes, analyst. 4. Diabase, Penn. R. R. tunnels, Weehawken; R. B. Gage, analyst. 5. Diabase, N. Y., Susquehanna & Western R. R. tunnel; R. B. Gage, analyst. 6. Diabase, road to West Shore Ferry, Weehawken; R. B. Gage, analyst. TRAP ROCK AND OTHER BASIC IGNEOUS STONES 75 7. Olivine diabase, second road to West Shore Ferry, Weehawken; R. B. Gage, analyst. 8, 9. Diabase, Englewood Cliffs; R. B. Gage, analyst. 10. Olivine diabase, Englewood Cliffs; R. B. Gage, analyst. 11, 12, 13. Diabase, quarry near Rocky Hill station; A. H. Phillips, analyst. 14. Hartshorn's quarry, near Springfield and Short Hills, lower " gray " layer; R. B. Gage, analyst. 15. Same locality, middle " black " layer; R. B. Gage, analyst. 16. Same locality, upper " gray " layer; R. B. Gage, analyst. 17. Hatfield & Weldon's quarry, Scotch Plains, lower " gray " layer; R. B. Gage, analyst. 18. Same locality, " black " rock above; R. B. Gage, analyst. 19. O'Rourke's quarry, West Orange. Large columns near the bottom. (Bull. U. S. Geol. Sur., No. 150, p. 255); L. G. Eakins, analyst. 20. Morris County Crushed Stone Go's, quarry, Millington, lower " gray " layer; R. B. Gage, analyst. 21. Same locality, middle " black " layer; R. B. Gage, analyst. 22. Same locality, upper " gray " layer; R. B. Gage, analyst. The following table contains a number of less complete com- mercial analyses of trap rock from various localities in New Jersey. TABLE 38A. TRAP: NEW JERSEY. 23 24 25 26 27 Silica 50 81 50 61 49 20 50 03 51 20 Alumina 13 25 18.34 14.50 18.20 20 88 Ferric oxide ) 14 66 13.91 17.01 16.81 11 12 Ferrous oxide ) Lime 10 96 7.01 7.50 11.10 12 50 Magnesia. . 6.97 6.73 6.30 1.02 2 17 Potash 1.71 1.08 ) Soda 0.76 1.60) 1.69 1.03 1.03 Water 0.88 1.72 3.80 1.81 1.10 23. Little Falls, Passaic County; W. C. Day, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 419. 24. Mine Brook, Somerset County; T. B. Stillman, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 419. 25. Millington', Morris County; T. B. Stillman, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 419. 26. Millingtonj, Morris County; T. B. Stillman, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 419. 27. Millington, Morris County; T. B. Stillman, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 419. 76 BUILDING STONES AND CLAYS TABLE 39. ANALYSES OF GABBRO: NEW YORK. i 2 Silica (SiO 2 ) 54 72 55 34 Alumina (A^Oa) . 17 79 16 37 Ferric oxide (Fe2Os) 2 08 77 Ferrous oxide (FeO) 6 03 7 54 Lime (CaO) 6 84 7 51 Magnesia (MgO). . 5 85 5 05 Potash (K 2 O) 3 01 2 03 Soda (Na 2 O) 3 02 4 06 Water 58 1. Quaker Bridge, N. Y.; H. T. Vulte, analyst; " Handbook of Rocks," 3d ed., p. 72. 2. Montrose, N. Y.; Dunn, analyst; "Handbook of Rocks," 3d ed., p. 72. TABLE 40. ANALYSES OF TRAP ROCK: PENNSYLVANIA AND VIRGINIA. 1 2 3 4 5 6 7 Silica Alumina Ferric oxide Ferrous oxide 46.87 13.36 9.79 2.71 52.65 17.02 4.61 45.73 13.48 11.60 47.87 14.43 11.55 52.06 13.67 15.97 51.31 13.64 0.52 50.88 13.17 1.11 Lime 14 70 6 35 9 92 10 45 8 15 12 41 10 19 Magnesia 4 35 2 87 15 40 10 58 5 01 12 73 13 05 Potash Soda 2.01 4 64 1 7 - 42 i 0.47 3 24 0.61 3 47 0.86 3 36 0.32 1 40 0.31 1 17 Carbon dioxide 1 Water > 9.03 0.94 1.82 1.05 0.14 1. Birdsboro, Berks County, Pa.; H. Fleck, analyst; 20th Ann. Rep. U. S. Geol. Sur., pt. 6, p. 435. 2. Rushland, Bucks Co., Pa.; Lathbury & Spackman, Analysts; Min. Res. U. S., 1903, p. 155. 3-5. Chatham, Pittsylvania County, Va.; T. L. Watson, analyst; Min. Res. of Virginia, 1907, p. 37. 6-7. North of Rapidan Station, Va.; T. L. Watson, analyst; Min. Res. of Virginia, 1907, p. 39. Physical Properties. Since the basic rocks are not ordina- rily attractive in color, there is little reason to quarry them unless they are entirely sound from a structural point of view. Com- TRAP ROCK AND OTHER BASIC IGNEOUS STONES 77 paratively few tests of the physical properties of basic stone are on record, but from those available it is obvious that in both strength and density they outrank the granites and other acid rocks. TABLE 41. PHYSICAL PROPERTIES OF AMERICAN TRAP ROCKS. State. Location. Tested by Specific gravity. Weight per cubic foot. Compressive strength, pounds per square inch. Min. Aver. Max. Connecticut New Haven .... New Haven .... Meriden Gillmore Hawes 2.60 2.86 2.965 3.10 2.802 2.80 3.005 3.000 2.704 3.03 2.96 2 928 162.5 175.1 175.0 i87!5 169.0 189.5 14,161 9.500 18.801 27.250 17.631 '26! 250 20.750 21.500 '24:046 20.250 21.035 Maine Watertown Gillmore Gillmore Gillmore Gillmore Gillmore Gillmore Hawes Gillmore J. S. Newberry. West Roxbury.. Duluth Duluth Tischer's Creek Taylor's Falls. . Beaver Bay .... Jersey City Jersey City Pompton Cortland Point. Quaker Bridge . Rushland Chatham Goose Creek. . . . Hapidan Minnesota New Jersey New York 2.65 2.953 3.026 3 095 164.4 Virginia Watson { Watertown Watson 23.000 Uses of Trap Rock. The basic igneous rocks included in this group could of course be used as building stone, or for any of the other structural uses to which granites are applied, but as a mat- ter of fact they are rarely so used. This lack of use for these purposes is due in part to the dark and somber colors usually characteristic of the basic stones; and also, in part, to their great toughness and the consequent difficulty and expense of dressing them for structural uses. Added to these disadvan- tages is the tendency, shown by many of the denser basic rocks, to break on blasting into masses whose size and shape render them unfit for use as dimension stone. On the other hand, the very features which render the traps generally unserviceable for structural purposes are of advantage 78 BUILDING STONES AND CLAYS for other uses. In consequence, trap rock and allied stones are largely used as paving blocks and, in the form of crushed stone, as road metal, railway ballast and concrete aggregate. For all of these purposes darkness of color is of no disadvantage, while density, strength and toughness are of direct service. Production of Trap Rock in the United States. Complete statistics covering the trap-rock production of the entire United States are unfortunately not available. This condition is due to the fact that in the statistical reports on the stone industry published annually by the United States Geological Survey the production of trap is, in most of the states, included with that of granite. The trap-rock production of the six most important producing states is, however, reported separately by the Geological Survey, and these partial statistics are quoted in the series of tables which follow. TABLE 42. TRAP-ROCK PRODUCTION OF THE UNITED STATES, 1899-1909. Year. Value. Year. Value. 1899 $1,275,041 1905 $3,074,554 1900 1,706,200 1906 3,736,571 1901 1,710,857 1907 4,594,103 1902 2,181,157 1908 4,282,406 1903 2,732,294 1909 5,133,842 1904 2,823,546 1910 6,452,121 The totals given in the preceding table, as in those which follow, cover the production of trap rock hi the states of Cali- fornia, Connecticut, Massachusetts, New Jersey, New York and Pennsylvania only. In addition to this, trap rock is quarried more or less steadily in Maine, Minnesota, Virginia, Oregon and Washington, but no exact data on the output of these states are available. TRAP ROCK AND OTHER BASIC IGNEOUS STONES 79 TABLE 43. TRAP-ROCK PRODUCTION BY STATES AND USES, 1908-1909. 1908. State. Building. Paving. Crushed stone. Other. Total. Road- making. Railroad ballast. Concrete. California $722 7,594 12,235 11,399 8',593 $114,996 8,125 "58^69 "2',835 $423,798 199,540 348,108 578,570 567,908 195,769 $148,154 100,000 30,695 182,355 20,580 201,091 $285,380 152,950 117,134 235,967 107,234 106,987 $6,089 5,010 500 13,054 28,231 2,634 $979,139 473,219 508,672 1,079,514 723,953 517,909 Connecticut. . . . Massachusetts . New Jersey. . . . New York Pennsylvania . . Total 40,543 184,125 2,313,693 682,875 1,005,652 55,518 4,282,406 1909. State. Build- ing. Paving. Crushed stone. Other. Total. Road- making. Rail- road ballast. Concrete. California Connecticut. . . Massachusetts. New Jersey . . . New York .... $900 6,827 13,250 1,496 $129,764 2,720 $799,846 292,451 337,839 664,571 662,448 281,467 $71,108 28,905 75,031 138,134 27,620 259,241 $361,255 33,369 247,382 232,262 70,708 165,449 $108,212 3,383 "il',729 l',240 $1,471,085 367,655 673,502 1,140,571 760,776 720,253 92,379 Pennsylvania. . Total 11,056 1,800 33,529 226,663 3,038,622 600,039 1,110,425 124,564 5,133,842 TABLE 44. PRODUCTION AND VALUE OF TRAP PAVING BLOCKS, 1908-1909. Paving blocks. State. 19( )8. 19 09. Number. Value. Number. Value. California. 2 765 587 $114 996 3 060 078 $129,764 Connecticut 232 160 8 125 80,590 2,720 New Jersey 1,665,983 58 169 2,105,720 92,379 Pennsylvania 63,000 2,835 50,000 1,800 Total 4 726 730 184 125 5 296 388 226 663 Average price per thousand 38.95 42.80 80 BUILDING STONES AND CLAYS List of References on Trap Rock. The following list con- tains the titles of a number of papers and reports dealing in one way or another with this subject. Many of the papers cited are primarily geological in their nature, and the list could have been greatly extended had more of this type been included. California: Anon. Trap rock in California. Bull. 38, Calif. State Mining Bureau, pp. 56-61, 154-164. 1906. Connecticut: Davis, W. M. The quarries in the lava beds at Meriden, Connecticut. Amer. Jour. Science, 4th series, Vol. I, pp. 1-13. 1896. Davis, W. M. The Triassic formations of Connecticut. 18th Ann. Rep. U. S. Geol. Sur., pt. 2, pp. 9-192. 1898. Georgia: MeCaltie, S. W. Roads and road-building materials of Georgia. Bull. 8, Georgia Geol. Sur., 1901. New Jersey: Lewis, J. V. The origin and relations of the Newark rocks. Ann. Rep. State Geol. N. J. for 1906, pp. 99-130. 1907. Lewis, J. V. Properties of trap rocks for road construction. Ann. Rep. State Geol. N. J. for 1906, pp. 165-172. 1907. Lewis, J. V. Petrography of the Newark igneous rocks of New Jersey. Ann. Rep. State Geol. N. J. for 1907, pp. 97-168. 1908. Lewis, J. V. Building stones of New Jersey. Ann. Rep. State Geol. N. J. for 1908, pp. 81-83, trap. 1909. New York: Eckel, E. C. The quarry industry in southeastern New York. 20th Ann. Rep. N. Y. State Museum, pp. 141-176. 1902. Newberry, S. B. Kersantite a new building stone. School of Mines Quarterly, Vol. VIII, pp. 330-333. 1887. Smock, J. C. Building Stone in New York. Bulletins 3 and 10, N. Y. State Museum. Virginia: Watson, T. L. Mineral Resources of Virginia, 1907, pp. 36-41, trap. CHAPTER V. SERPENTINE AND SOAPSTONE. Relation of Serpentine and Soapstone. Two classes of rocks serpentines and soapstones will, for convenience, be con- sidered together in the present chapter. The two classes have, in fact, many points of resemblance so far as origin and character are concerned; though industrially they are often applied to widely different uses. Both serpentine and soapstone are hydrous magnesian silicates; and both have originated through the hydration of basic silicate rocks or minerals. Neither serpentine nor soapstone is there- fore directly igneous in origin, but rather a secondary result of the alteration of an igneous (or metamorphic) rock or mineral. Their close relationship chemically, as well as their principal points of difference, are well brought out when their analyses* are compared, as below. Silica. Magnesia. Water. Serpentine Per cent. 44 14 Per cent. 42 97 Per cent. 12 89 Soapstone (talc) 62.00 33.10 4.90 On comparison of these analyses it will be seen that both of the rocks under consideration are, when theoretically pure, hydrous silicates of magnesia;- and that they differ only in the relative proportions of their three essential constituents silica, mag- nesia and combined water. In the following sections of this chapter, the origin and charac- ters of serpentine will first be discussed, after which a brief con- sideration will be given to the soapstones and allied products. SERPENTINE. Serpentine, Ophicalcite, and Ophimagnesite. The term ser- pentine is applied to a series of soft greenish rocks composed largely or entirely of the mineral serpentine, which, in turn, is a * Quoted from Kemp's " Handbook of Rocks," 3d ed., pp. 140, 141. 81 82 BUILDING STONES AND CLAYS hydrous silicate of magnesia. The term ophicalcite is applied to crystalline marbles containing disseminated seams, streaks, or masses of the mineral serpentine. The term ophimagnesite, used in this volume for the first time, is suggested to cover the common but rarely recognized phase in which the rock is crys- talline magnesite, containing disseminated serpentine. Origin of Serpentines. Though serpentine is not strictly speaking an igneous rock most large serpentine deposits have been derived from the alteration in place of basic igneous rocks. A few deposits (including the ophicalcites) owe their origin to a less direct process, involving the metamorphism and crystalliza- tion of an impure limestone, and the subsequent alteration of the magnesian silicate minerals developed in the crystalline marble. These two methods of origin, which differ somewhat in results as well as in process, will be briefly described below; while, for a more complete discussion of the subject reference should be made to the papers cited in the list on page 87, and particularly to those by F. J. H. Merrill and G. P. Merrill. (1) Though other methods of origin have at times been sug- gested, it may be taken as proven that the bulk of the larger and purer deposits of serpentine everywhere have originated from the alteration (hydration) of basic igneous rocks, rich in magnesian silicate minerals. The particular minerals which appear to be the commonest source of serpentine are olivine, pyroxene, and hornblende. All of the minerals named are more or less basic silicates of magnesia and iron. When subjected to surface weathering, or to the continued action of waters at or near the surface, they are decomposed with the formation of hydrated magnesium sili- cates and iron oxide. Among the hydrated silicates so formed, serpentine is commonly the most abundant. (2) A second class of serpentine deposits, much less common though still of considerable commercial importance, originate in a way differing slightly in detail from that last discussed. This class includes the ophicalcites, in which serpentine masses, seams, or stringers are scattered through a ground mass of crystalline marble. In this case, the process of origin appears to have in- cluded several steps. In the first place, an impure limestone, carrying considerable silica, was metamorphosed so as to become thoroughly crystalline. During this change, the impurities of SERPENTINE AND SOAPSTONE 83 the limestone, with possibly some additional matter from other sources, crystallized out separately in the form of various sili- cate minerals; so that the result of the metamorphism was the production of a crystalline marble through which were scattered crystals of hornblende, pyroxene and other silicate minerals. Later, these silicates were hydrated to serpentine, so that an ophicalcite was produced. Chemical Composition of Serpentine. Though the chemical composition of the mineral serpentine is definite enough, wide variations in composition are shown by stones which are grouped commercially under the same name. The two tables which follow contain a number of analyses of normal serpentines, of ophicalcites and of ophimagnesites from various American localities. TABLE 45. ANALYSES OF SERPENTINES. 1 2 3 28.80 5.54 Yeo 4.75 0.33 34. 41 4 * 5* 40.06 1.37 3.02 '3:43 0.20 39.02 6t 7 8 45.02 3.35 37 '.75 {::: 9 41.55 10 11 Silica (SiO 2 ) 39.48 34.84 0.42 Y'eios i 1.85 0.68 7.02 30.74 0.07 43.87 0.31 'i'.ii '6^62 38.62 40.39 1.01 6.22 '6: Organic matter ) Moisture 11 12 13 14 15 16 17 Silica (SiO 2 ) . 66 16 68 79 69 04 69 07 67 90 64 00 63 22 Alumina (Al 2 Oa) . . . 8 62 14 26 12 66 11 40 10 42 11 59 16 76 Ferric oxide (Fe 2 O 3 ) Ferrous oxide (FeO) 9.04 3 44 5.90 1.16 8.55 1.30 7.66 1.04 6.22 13.71 9.54 Lime (CaO) 1.77 1.40 1.75 1.56 3.17 1.56 1 75 Magnesia (MgO) Potash (K 2 O) .78 4 96 1.43 3.09 1.87 2.98 3.14 3.88 4.34 4 11 2.03 1 36 1.52 1 43 Soda (Na 2 O) .64 .09 .09 .96 69 64 07 Sulphur in SO 3 Sulphur in FeS 2 Carbon (C) .08 .02 2.10 .44 .01 2.01 .06 .01 tr. .02 .01 .06 .01 1.78 .05 .04 4.03 .05 .03 3.70 Carbon dioxide (CO 2 ) Water . . . .09 .18 .11 .47 .72 .84 .11 .24 .01 .23 .01 57 .01 1 01 Analyses 1-10 inclusive of the preceding table were made at a laboratory formerly maintained in St. Louis by one branch of the United States Geological Survey, but not manned by Survey chemists. The analyses are quoted from Bulletin 430, United States Geological Survey, page 334, and are repeated here for what they may be worth. In the writer's opinion they are as doubtful as those formerly turned out at the Watertown Arsenal. Analyses 11-17 are quoted from Bulletin 275, United States Geological Survey, page 53, where they are credited to W. G. Waring. In this set the alumina is as remarkably low as it was high in the other series. Taken together the two sets, which cover much the same slates, are excellent examples of what may SLATES 107 be expected when difficult analyses are turned over to ordinary chemical laboratories. The localities are as follows: 1, 4. Red slate, Southwestern Slate Company. 2, Green slate, Southwestern Slate Company. 3, 5. Black slate, Harrington property. 6, 7. Green slate, Jones property. 8, 9. Red slate, Jones property. 10. Buff slate, Baker property. 11. Green slate, Southwestern Slate Company. 12. Red slate, Southwestern Slate Company. 13. 14. Red slate, State House Cove. 15. Green slate, State House Cove. 16, 17. Black slate, Crooked Creek. TABLE 60. ANALYSES OF SLATES : CALIFORNIA, UTAH. 1 2 3 4 Silica 63.52 47.30 45 15 54 05 Alumina 16.34 15.53 16 33 20 95 Iron oxides 6.79 8.00 8.42 9 28 LJrne 0.98 7.83 6.42 22 Magnesia 2.50 7.86 8.72 12 Potash and soda n.d. 3.17 n.d. n.d Water, carbon dioxide 4.86 9.92 11.28 3 90 1. Black slate, sedimentary; Eureka Slate Company, Kelsey, El Dorado County, Cal.; sampled by E. C. Eckel; analyzed by W. T. Schaller. 2. Green slate, igneous; same quarry as preceding; analysis quoted by company. 3. Green slate, igneous; same quarry as preceding; sampled by E. C. Eckel; analyzed by W. T. Schaller. 4. Purple slate, near Provo, Utah; sampled by E. C. Eckel; analyzed by W. T. Schaller. TABLE 61. ANALYSES OF EUROPEAN ROOFING SLATES. 1 2 3 4 5 6 7 8 9 10 11 12 13 Silica (SiO 2 ) 55.06 58.30 50.88 55.8 59.3 60.50 60.68 61.43 61.57 65.63 48.60 59 35 67.56 Alumina (A1 2 O 3 ) 22 55 21.89 14.12 25.7 17.5 19.70 21.20 19 10 19 22 20 20 23.50 18 56 12.23 Ferric oxide (FejOa) . . . 1.97 7.05 0.3 2.3 7.83 5.68 4.81 6.63 2.72 11.30 1 10 2 87 Ferrous oxide (FeO) . . . 5.96 2.57 9.96 9.5 3.8 46 3 12 1 20 85 4 75 6.99 Lime (CaO) 1.30 0.39 8.72 4.4 5.0 1.12 1.71 0.31 0.22 0.19 5 20 27 Magnesia (MgO) Soda (Na 2 0) 2.92 2 17 1.09 1 18 8.67 tr. 2.20 2 20 0.88 ?, 09 2.29 0.83 0.93 3.63 0.71 3.81 1.60 3.60 (1 48 3.03 1.28 Potash (K 2 O) 3.82 2.45 0.88 3.18 3 64 3.24 1 4. 70 11 77 1 76 Carbon dioxide (CO 2 ) . . 6.47 3.2 2.4 4.45 Water 4.35 4.ei 0.2 6.0 3.30 2.88 3.52 3.25 3.17 7.60 3.41 1.00 108 BUILDING STONES AND CLAYS 1. Mohradorf, Austria; Nikolic, analyst; 19th Ann. Rep. U. S. Geol. Sur., pt. 3, p. 261. 2. Delabole, Cornwall, England; J. A. Phillips, analyst; 19th Ann. Rep. U. S. Geol. Sur., pt. 3, p. 261. 3. Lake District, Westmoreland, England; G. Vogt, analyst; Jour. Inst. British Architects, Vol. 3, p. 196. 4. 5. Lake district, Westmoreland, England; Lock, analyst; Economic Mining, p. 367. 6. Average, Wales; Hull, " Building Stones," p. 291. 7. Llanberis, Wales; 19th Ann. Rep. U. S. Geol. Sur., pt. 3, p. 261. 8. Rimogne, Ardennes, France; Klement, analyst; 19th Ann. Rep. U. S. Geol. Sur., pt. 3, p. 261. 9. 10. Fumay, Ardennes, France; A. Renard, analyst; 19th Ann. Rep. U. S. Geol. Sur., pt. 3, p. 261. 11. Angers, France; D'Aubisson, analyst. 12. Frankenberg, Prussia; A. von Groddeck, analyst; 19th Ann. Rep. U.S. Geol. Sur., pt. 3, p. 261. 13. Westphalia, Prussia; H. von Decken, analyst; 19th Ann. Rep. U. S. Geol. Sur., pt. 3, p. 261. COLOR, TEXTURE AND STRUCTURE. Color of Slates. Slates from various districts, and in some cases even from different parts of the same quarry, show very marked differences in color. The commonest colors are various shades of gray and bluish gray. Black is probably the next most abundant color, followed in turn by reds of various shades. Greens are less common, especially the purer and clearer greens, though grayish green is not rare. Purple is perhaps the scarcest of the colors in which slate is found. Yellow, brown and buff slates occur, but these colors are invariably due to weathering and though showing at the surface do not occur in the merchant- able slate. In almost all cases, the colors shown by slates are due to the amount and condition of two of the constituents of the slate organic matter and iron oxides. It may be fairly assumed that the normal or average slate color is some shade of gray. If the slate contains considerable finely divided carbonaceous matter, it will probably show a glossy black color on its cleavage surfaces. If it is high in ferric iron, it will probably be a red or purple slate. If the iron is in the ferrous form, the slate will normally be green, if fairly free from organic matter; and black if organic carbon is present in addition to the ferrous iron. SLATES 109 Economic Importance of Color. The color of slate is of im- portance industrially in so far as it affects the physical properties, the permanence and the salability of the product. So far as strength is concerned, there is little to choose between the various colors. The glossy black slates are, on the average, apt to be somewhat finer grained, somewhat softer, and con- siderably more smooth and even grained than those of any other color. The gray slates, on the other hand, usually are at the other extreme of the series in all of these respects; while the red and green slates are intermediate. The properties in which the black slates excel are obviously those which fit them well for mill stock; while they are negative or actually harmful so far as strength and durability are concerned. In regard to permanence of color throughout long exposure to the weather, which is a matter of importance in the selection of roofing slates, slates may be either practically permanent in tint, they may fade evenly and slightly or they may fade or discolor in uneven patches. Except for the difficulty in matching the tint when a few slates on a roof require replacement, there would be no objection to a moderate and even fading, while of course a slate which changes color in blotches is highly objectionable. So far as original color affects these matters, it may be said that the black and gray slates are commonly either entirely permanent in color, or show but slight changes; that the bluish slates often turn more grayish, while most red slates take on a browner tint. The green slates are the most doubtful always, for while some of them are practically permanent in color, others discolor badly. The change in color of the fading green slates is due, according to Dale and Hillebrand, to the presence of small quantities of unstable iron-lime-magnesia carbonates, in which the ferrous iron gradually oxidizes and hydrates to limonite. The develop- ment of discoloring blotches in slate of any tint is generally due either to the same cause, or to the weathering of small grains of iron sulphide (pyrite or marcasite). The salability of slate is largely influenced by color. As the entire slate trade is governed by tradition, it being in this respect perhaps the most archaic of existing industries, it is very difficult to introduce a new slate, and particularly so if its color differs from that to which the particular local market is accustomed. When a new company attempts to do this, its competitors never 110 BUILDING STONES AND CLAYS have the slightest difficulty in producing a hundred ancient Welshmen who are willing to swear that, in all the years since Wales first rose above the sea, no one has appeared mad enough to even suggest using a slate of that particular tint for roofing purposes. It is only recently that the slate trade has thought of submitting such matters to laboratory tests, in place of relying on the traditional lore of the bards. There is a very definite advantage to a slate company arising from the control of two or more colors of slate, whether these are taken from the same quarry or from entirely different dis- tricts. Architects usually specify color as well as grade, and a company which can supply only one good color or type of slate must necessarily lose a good deal of desirable business. A good example of the advantage of controlling two well-contrasting colors is afforded by a western company whose quarry is in a glossy black slate, but with a few narrow bands of green slate. The latter is marketed for lettering and ornamental work on the black slate background, and the idea has taken very satisfac- torily. In the eastern states the slate industry seems to be on the verge of developing on a larger scale than heretofore, and doubtless this development will ultimately take the form of large companies each owning a number of quarries in different districts, so that each can supply slate of any specified grade and color. Cleavage. The most striking difference between slates and shales lies in the fact that while shales ordinarily break into irregular blocks, slates show a very perfect cleavage in one plane, though breaking irregularly in all other directions. This slaty cleavage is a phenomenon closely akin to the gneissoid lamination shown by many granites, and discussed on an earlier page. In neither case is the cleavage nor banding necessarily parallel to earlier bedding planes. In slates, for example, it is occasionally found that the cleavage plane intersects the original bedding plane at a high angle; and indeed most books dealing with the subject allow it to be supposed that such discordance between cleavage and bedding is the normal condition. The writer's experience, however, is that in by far the majority of cases the cleavage of our commercial slates is either absolutely parallel to the original bedding, or else diverges from it at only a small angle. SLATES 111 When the bedding plane and plane of slaty cleavage coincide exactly, so that the slate splits most readily along its original bedding planes, the split surface will usually be rough and un- even, so that such a slate does not give satisfactory roofing material but must be used as mill stock. Surface weathering decreases the durability and the splitting properties of slates. For this reason it is difficult to decide as to the value of a slate property from surface exposures only. It may be taken as a general rule that the deeper from the surface, the better the slates will be as to soundness, strength, color, cleavage and size of blocks. This rule is not invariable, however, and it cannot be carried too far. Slate from an opening 50 feet below the surface will almost always be superior in every way to surface slate; but slate from a 100-foot hole should not be expected to be much if any better than that from a 50-foot hole. PHYSICAL PROPERTIES AND TESTING. Desirable Properties of Slates. Slate may be used for two general purposes mill stock and roofing slate; and the prop- erties which are desirable for one use are not necessarily im- portant for the other, a fact which is often overlooked. For mill stock a slate should preferably be fine and even- grained, soft rather than hard and reasonably uniform in color. For the sake of the dressing machinery it should be free from grains of quartz, pyrite or other hard minerals. Its color and chemical composition are of no particular importance for such use. For roofing slate durability and strength are of value. A roof- ing slate should be practically permanent in color, even after exposure to damp and acid atmospheres; it should stand punch- ing cleanly, and should be strong and tough enough to stand rough handling during shipment, laying and use. Pyrite, iron carbonate and other unstable minerals are highly undesirable. It will be seen from the above summary that no one is par- ticularly interested in the compressive strength of roofing slate and still this is occasionally determined and recorded with proper solemnity. The specific gravity is of interest chiefly because a dense heavy slate may be expected, other things being equal, to be more durable than one of more porous nature. 112 BUILDING STONES AND CLAYS TABLE 62. SPECIFIC GRAVITY OF ROOFING SLATES. Quarry. Location. Tested by Specific gravity. Eureka quarries Poultney Vt W F Hillebrand Eureka quarries Poultney, Vt. W F Hillebrand 2 onto Hughes quarry Pawlet, Vt. W F Hillebrand 27Q1 Auld & Conger Wells, Vt W F Hillebrand 2 7627 McCarty quarry American Black Slate Co American Black Slate Co American Black Slate Co. . South Poultney, Vt Benson, Vt Benson, Vt Benson, Vt W. F. Hillebrand. . W. F. Hillebrand.. W. C. Day W C Day 2.8064 2.7748 2.764 2 786 National Red Slate Co Raceville, Washington Co., N. Y. 2 7839 National Red Slate Co Raceville, Washington Co., N. Y. 2 7171 Empire Red Slate Co Granville, Washington Co., N. Y. 2 8085 Peach Bottom, Pa.-Md.* Chapman, Pa Albion, Pa.* Bangor, Pa.* Westmoreland, England M. Merriman E. S. Bailey M. Merriman M. Merriman G. Vogt. 2.894 2.79 2.775 2.780 2 77 Delabole, Cornwall, England. . . Mohradorf, Austria, Silesia Lake District, England J.A.Phillips Nikolic 2.81 2.78 (2.775 (2.8 Average of 12 specimens. TABLE 63. COMPARATIVE TESTS OF ROOFING SLATES. (MERRIMAN.) 1 o> S8 >> _. ^_ iff l!| Q a ills III fl.s Locality. Color. f*si| ' gS| "1 c g^S g fcjj Hie 13 '55 3 s ft! I'll* | B ill! ||.s | s l Epl 1 i| I* 5|' Maine district: Merrill Slate Co., Brownville. Gray 9,880 0.200 2.798 0.265 0.148 0.305 Monson Consol, Slate Co., Monson Gray 9,130 0.205 2.794 0.256 0.188 0.286 New York- Vermont district: Matthews Slate Co., Granville Green... 8,050 0.190 2.783 0.226 0.374 0.379 Matthews Slate Co., Granville Red 9,220 0.232 2.848 0.148 0.243 0.373 Vermont Green Slate Co Green 6,410 0.225 2.771 0.341 0.231 0.295 Rising & Nelson Green 7,250 0.207 2.736 0.190 0.325 0.768 Lehigh district: Penn.-N. J. Chapman Slate Co., Chapman, Pa Dark gray 9,460 0.212 2.764 0.208 0.231 0.383 Albion quarry, Pan Argyle Old Bangor quarry, Bangor 7,150 9,810 0.270 0.312 2.775 2.780 0.238 0.145 0.547 0.446 Peachbottom district: Penn.-Md. Locality not stated 11,260 0.293 2.894 0.224 0.226 Virginia district: Williams Slate Co., Arvonia . . Dark gray 9,040 0.227 2.781 0.060 0.143 0.394 Pitts quarry, Arvonia Dark gray 9,850 0.225 2.791 0.108 0.216 0.323 List of References on Properties and Testing of Slates. The following brief list will serve to direct the reader's attention to SLATES 113 the only papers on this subject which seem to contain matter of serious importance. Dale, T. N. Slate deposits and slate industry of the United States. Bui. 275, U. S. Geol. Sur., pp. 45-50, 122-125, on tests of slate. Merriman, M. The strength and weathering qualities of roofing slates, Trans. Amer. Soc. Civil Engineers, Vol. XXVII, pp. 331-349. 1892. Merriman, M. The strength and weathering qualities of roofing slates, Trans. Am. Soc. C. E., Vol. XXXII, pp. 529-543. 1894. Merriman, M. Recent tests of various roofing slates. Bull. 275, U. S. Geol. Sur., pp. 122-124. 1906. DISTRIBUTION AND PRODUCTION OF SLATE. Geologic Distribution of Slates. The formation of a deposit of roofing slate, as has been explained in previous sections, in- volves the existence of clayey sediments in an area which under- goes extreme metamorphism. The geologic age of the original clay beds does not enter into the problem, except that as a general thing the older beds, having a longer history, have had more chance of being metamorphosed. But unless the inquiry be limited to particular geographic or geologic areas, it is not pos- sible to say in advance that the rocks of any particular geologic period are likely to be slate-bearing. If, however, the question is so limited to particular areas, geologic history will afford some guidance in the search for slate. In the eastern and southeastern United States, for example, all of the known slate deposits are of either Cambrian or Ordovician age; because in the New England and Appalachian region these rocks were involved in the general metamorphism of the region while the Carboniferous and newer rocks were deposited after the bulk of the metamorphic action had ceased in this area. In the western states, on the other hand, where earth movements of great intensity took place much later in geologic history, we find clayey sediments of Jurassic age converted into slate. The slates of the Lake Superior region, in Michigan and Minnesota, are even older than those of the eastern states, for all of the Lake Superior slates date back to pre-Cambrian time. Geographic Distribution of Slates. The geographic distri- bution of slate deposits in the United States, as may be inferred from the preceding section, is fixed by the geologic history of the various portions of the country. Wherever clayey sediments have existed in any region, during a period when the region in 114 BUILDING STONES AND CLAYS question was subjected to metamorphic action, we may fairly expect to find that in part of their extent at least these clayey sediments have been converted into slates. Since the physical results of earth movements are most extreme in cases where relatively soft rocks are pressed against or between masses of harder rocks, it is natural enough to find that slaty cleavage is best developed under these conditions. Accordingly, practically all of the important slate deposits occur in areas where clayey sediments had been deposited along an older granite shore line; and where these sediments were later pressed against the less yielding granites and gneisses. In New England and the Appa- lachian region the clayey sediments were deposited during the Cambrian and Ordovician periods along a shore line of pre- Cambrian gneisses and schists; and during subsequent earth movements many of the sediments were turned into slates. In the Lake Superior, Ozark and Rocky Mountain regions a similar sequence of events took place, though not at the same periods in the earth's history. The geologic history of slate deposits therefore limits their possible geographic distribution, so that we find all of the important slate deposits of the world fringing older igneous masses. Chief American Quarry Districts. For local details concern- ing the various slate deposits of the United States, reference should be made to the official report by Dale and others noted in the bibliography on page 125 of this volume. In the present place only brief mention will be made of the more important American slate districts. The map accompanying Dale's report shows the location of the present producing districts, as well as of a number of the more promising prospects. For a reason suggested in the previous section, the American slate districts follow in their general distribution the granite areas. We have, therefore: 1. Extensive slate deposits along the Appalachian belt, from New England to Alabama. In this region the slates are all of Cambrian or Ordovician age, and represent original clayey beds which were violently stressed against and between the older and more resistant masses of pre-Cambrian granites, gneisses and schists. The principal producing areas within this extensive general belt are the isolated Monson district of Maine; the im- portant area along the New York- Vermont border; the Lehigh SLATES 115 region of Pennsylvania-New Jersey; the Peachbottom region of Pennsylvania-Maryland; the separated Esmont, Arvonia and Snowden areas of Virginia; and less well-developed areas in eastern Tennessee and northwest Georgia. 2. Extensive but little developed slate deposits bordering the massive rocks of the Lake Superior region, in Minnesota and Michigan. 3. Separated small areas in Texas and Arkansas, fringing regions of great local earth movement. 4. Scattered and mostly undeveloped areas along the Rocky Mountain and other western mountain chains; the only developed district being in central California. Chief Foreign Districts. British slates are obtained principally from three districts: North Wales, Cornwall and Westmoreland. The Welsh slates are green, purple, black and pale gray in color; are quarried largely near Llanberris, Penrhyn, Ffestiniog, Llangollen, Carnarvon and Bangor; and are shipped from Portmadoc and other ports. The Cornish slates are gray to bliie' nr cdlbr, are quarried at Delabole and shipped from Tintagel and Boscastle. The slates of the Lake district of Westmoreland are light blue to light green in color, are quarried near Kendal and are rarely exported. Other districts in England, as well as in Ireland and Scotland, produce smaller amounts of slate. The principal slate deposits of France are located in two quite distinct districts, one being near Angers in the Department of Maine et Loire and the other in the Ardennes. The slates quarried in the first district, at Angers and Poligny, are dark blue in color and are shipped from Nantes. The Ardennes slates are quarried at Rimogne, Fumay and Deville. Dressing of Roofing Slates. Roofing slates pass through' three operations blockmaking, splitting and dressing be- 1 fore they are ready for the market. At times they are further! subjected to punching or to counter-sinking, according to the requirements of the purchaser. All of these operations were for- merly carried on by hand, and at most small quarries and some large ones hand labor is still depended on for most of the work. Some of the operations can, however, be done more economically 1 by machinery. The slate is hoisted from the quarry in slabs which average perhaps 6 feet by 3 feet by 1J feet. When hand dressing is. Fig. 17. Slate dressing: the dressing sheds. [116] Fig. 18. Slate dressing: the beginning of sculping. SLATES 117 depended on, these slabs are loaded on a tram car and pushed to the dressing sheds, a series of little sheds or cabins each occupied by a dressing gang. A dressing gang includes three men a blockmaker, a splitter and a dresser. Ordinarily each gang takes contracts from the company at a fixed price per square of finished slate, the receipts being divided by the three members of the gang in fairly equal proportions, though the dresser or Fig. 19. Slate dressing: sculping. , trimmer usually gets a little less than the other two. The work is divided and carried on as follows: The blockmaker takes the large slabs or blocks above noted and cuts them into manageable slabs about 2 feet by 1J feet in size and 2 inches thick. This is done with the chisel. In making the cut across the grain the operation is called " sculping," and is shown in Figs. 18 and 19. A F-shaped notch is first cut in one side of the slab with the gouge (Fig. 18), after which the splitting chisel is held with edge vertical in this notch and struck with the hammer (Fig. 19). The slab is now passed on to the splitter, whose special tool 118 BUILDING STONES AND CLAYS is the thin splitting chisel (Fig. 20), 10 to 15 inches long, and with an edge 2 to 3J broad. One or more of these are driven into the slate, along some cleavage plane, with the maul, and are then worked backward and forward by hand until the slate splits. The splitting is continued until the slates are reduced to the proper thickness, which may be from one-eighth to one- fourth inch. The slates, now of proper and uniform thickness, Fig. 20. Slate dressing: splitting. but of irregular shapes, are given to the dresser or trimmer, who formerly trimmed them to size with a knife. At present hand- or foot-power dressing machines are employed every- where the general design being a long knife, set vertically and hinged at one end, while the other end is alternately raised and lowered by hand or by a treadle. At a large Pennsylvania quarry the slate blocks were delivered by the company in front of the dressing sheds, and tools were furnished and sharpened at company expense, while the dressing gang received the following prices per square of finished slate : SLATES 119 No. 1 quality $1.10 per square Intermediate quality 1.00 per square No. 2 quality 90 per square It has been noted that machine work is now employed for some of these operations. Splitting is still done by hand labor, as 1 , mechanical splitters have rarely given good results. The blocks,, however, are usually given at least one sawed edge before being, handed to the splitter, this being done on a sawing table with vertical saw, such as is used in preparing mill stock. Measurement of Roofing Slates. Two different units of measurement are employed in the slate trade, the square and the mille, the former being used at all American quarries, while the latter is found in French and English markets. iflr LJ_LJ_I_LJ Fig. 21. Laying of roofing slate. The square is the number of slates of a given size necessary to cover 100 square feet of roof, with a given lap. Let b equal breadth of slates, d equal length of slates and I equal lap. Then the number of slates to the square will equal 14,400 = bd ~~bl ^ r-j- This formula may be used for computing the number of 120 BUILDING STONES AND CLAYS slates to the square for any given size and lap; but for convenience table 64 is inserted, which gives this information for the ordinary sizes of slates with a three-inch lap. TABLE 64. NUMBER OF SLATES PER SQUARE. Size of slate. Number of slates per square. Size of slate. Number of slates per square. Size of slate. Number of slates per square. 7X3 2400 10X 7 588 16X10 222 7X4 1800 10X 8 515 16X12 185 7X5 1440 12X 6 534 18X 9 214 8X4 1440 12X 7 458 18X10 192 8X5 1152 12X 8 400 18X11 175 8X6 960 12X 9 356 18X12 160 9X4 1200 12X10 320 20X10 170 9X3 960 14X 7 374 20X11 154 9X6 800. 14X 8 328 20X12 142 9X7 686 14X 9 291 22X11 138 9X8 600 14X10 262 22X12 127 10X4 1039 14X12 219 24X12 115 10X5 822 16X 8 277 24X14 98 10X6 685 16 X 9 247 The mille, which is a unit much used in Europe, is nominally 1200 slates of any given size. As slates are shipped at the pur- chaser 's risk, however, 60 slates are added to cover breakage, so that the actual mille contains 1260 slates. The number of squares in a mille will of course vary according to the size of the slate. In the English and Welsh slate trades certain fanciful names have long been used for the different sizes of roofing slates. These names are not always uniformly applied in the different British slate districts, and of late years they seem to be falling some- what into disuse. But as they are still frequently met with both in export business and in trade literature the following table* has been inserted in explanation of the terms. * Notes on Building Construction, Part III, p. 29. SLATES 121 NAMES AND SIZES OF BRITISH SLATES. Sold by weight. Size. Sold by aize. Size. Queens . . . Inches. 36X24 Ladies, large. . . . Inches. 16 X 8 Rags. . 36X24 Ladies, small 14X12 Imperials. 30X24 Ladies, small 14X10 Sold by size. Empresses 26X15 Ladies, small Ladies, small Doubles 14X 8 14X 7 13X10 Princesses 24x14 Doubles 13X 7 Duchesses 24x12 Singles 12X 8 Marchionesses 22X12 Singles 12 X 6 Marchionesses small 22X11 Singles llX 6 Countesses 20X10 Singles 10 X 8 Viscountesses 18X10 Singles 10 X 6 Viscountesses small 18 X 9 Singles 10X 5 Ladies, large 16X10 Thickness. The thickness of a roofing slate varies usually with the size of the slate, decreasing with its area. In Welsh practice* the following rule is observed: Size of slate. Thickness. First quality. Second quality. Inches. 22X11 to 24X12 16X 8 to 20X10 13X 7 to 14X12 Inch. ! Inch. Slates are graded according to their smoothness of surface, even thickness, and (in some districts) uniformity of color. Usually two grades will cover the output of any given quarry, but occasionally a third grade is employed. Roofing slates are always cut so that the longer sides of the slate are in the direction of the grain. This is done not only to secure ease of dressing, but to give additional security for slate roofs. If a slate so cut be broken while on the roof, the fracture will be in the direction of the grain, and the two fragments of the slate will still be held by single nails; while if the slate had been cut in the opposite direction (i.e., longer sides across the grain) the lower part of a broken slate would have nothing to hold it on the roof. * Notes on Building Construction, Part III, p. 28. 122 BUILDING STONES AND CLAYS Statistics of Slate Production. The following statistical tables are quoted from the current volume of Mineral Resources United States. The following table shows the total value of the slate produced in the United States from 1905 to 1909, inclusive: TABLE 65. VALUE OF SLATE PRODUCED IN THE UNITED STATES, 1905-1909, BY STATES. State. 1905 1906. 1907. 1908. 1909. Arkansas $10,000 $5,000 $8,500 $2,500 California 40,000 80,000 60,000 60,000 * Georgia 7500 5,000 * IVlaine 224,254 238,681 236,606 213,707 $227,882 Maryland 151,215 130,969 116,060 102,186 129,538 New Jersey 5,360 8,000 j * New York Pennsylvania Vermont Virginia 66,646 3,491,905 1,352,541 146,786 72,360 3,522,149 1,441,330 172,857 83,485 3,855,640 1,477,259 173,670 > 130,619 3,902,958 1,710,491 194,356 I 107,436 2,892,358 1,841,589 180,775 Other States t 61,840 Total 5,496,207 5,668,346 6,019,220 6,316,817 5,441,418 Included in " Other States." t Includes California, Georgia and New Jersey. The following table shows the value of slate produced for roofing and for mill stock from 1905 to 1909, inclusive: TABLE 66. VALUE OF ROOFING SLATE AND MILL STOCK, 1905-1909. Roofing slate. Value of mill stock. Total value. Number of squares. Value. 1905 1906 1907 1908 1909 1,241,227 1,214,742 1,277,554 1,333,171 1,133,713 $4,574,550 4,448,786 4,817,769 5,186,167 4,394,597 $921,657 1,219,560 1,201,451 1,130,650 1,046,821 $5,496,207 5,668,346 6,019,220 6,316,817 5,441,418 The following table shows the average price of roofing slate per square in the entire United States since 1902: 1902. 1903. 1904. 1905. $3.45 3.88 3.78 3.69 1906. 1907. 1908. 1909. $3.66 3.77 3.89 3.87 SLATES 123 5 si fit III I i So| I I . ^i O T= f- t^. < O O CO O OO O 050io6 o't-i o'oo^-li-i co o o'ooooo'oo'ooo CO "I o IOO*OIO. 00 OOOO OSOOOSt>.|>. !>. OS OS OS OS OS OS 00 OO OS OS OS in ' ' ' ' ,J ^ =j * ^'oe-s^'o-S'S J^ be ^'g v ^3 Tg T3 'c'oi'^^ 7 ^ ^ a2 g- I a s-l^^o g "; 'g. J^ ^ a -g^ ITS I jr ll lii-h 2 1j Ill^llill 1 ^ fe tfo O^PQHO O P5W 132 BUILDING STONES AND CLAYS I loco S : ^ 66-^^ -os -co I j dd d d : : : : .... cO OO 1 s * *O I s * CO O5 CO ;2 .. 00 O T-H T* T-l ^. " ,3 : : : : : d S J >- -a os co d i c^i oo oocoo> I-T ii O g ^CN-rH ^ ? ' < ^^ ^H c^ O5 ^5 * ^^ ^^ ^^ ^^ 1 "~* ^* ^^ ^* ^^ * ^^ ^^ ^^ ^^ '""^ ^** ^^ ^^ ^ -J dd : d^ d : ddddd odd o' : d dddddi-id P S 3 Q ^< *O C^l C^ ^2 CO a Oi ^^ CO *^ OO "^t* ^ Ag c T^ ^^ 4 s * ^^ ^O ^ ^O ^^ CO CO i-H CO *"H CO CO ^^ "^ O5 "* t^* CQ O5 CO C^ _. .. I-H O O O O -CO I O OCO^fP-l'O^lO OOCOCO lOOt>- i ICOOCOC^^T I ^jn t^ t > CO ^H OO OO CO OS OS OS t^ OO ' H O5 OO '^ ^^ Is* OO ^^ 4 s * OO ^^ i^ OSOSt^- O5OS OSO51>-OSO5O5OS O000t>- t>-OOOS OSOSOOOsb-OOOO g ' < z ^ i i i I 1 _'^SOQ 4J"^ fl-- -<-3 a) W g =3~ : cc a : : c > H^ O JS - . 03 . ^ '5 X3 bs 2 ^ """ -d W nJ fe T3 ^'g ^^S O a>^C,2 g Hlirtf-i. M ii.pl- >> T3 J* fl o o 5 ->> g S W S chigan SANDSTONES 133 rH O O O O rH CO rH i rH C^ -^ O rH r- * i-H O 1 HO :^g co : o Tl i i it^-^HCO i i T-I (N OOOO O TH'^H' (NOOOO "" O CO CO I-H T*< (M O O CO rH rH CO O -00 t>- CO W CO O C. i I 00 CO rH OS t O OS rji 00* Tji 1C CO rH t^i CO rH d d 00* -CO rH rH rH rH rH ' !2 ! ( |i it ill iii I |g S^ 3Sl ill 1 i .1 "3 -fl .2 .2 E s 134 BUILDING STONES AND CLAYS i ^^ t> C? C^ t> CO OO *< 00 CO ^O O 1 is 38 i s -co 31 o o oo 1 :::::::::::::.::: 00 CO Tf <5 o * r-> (N . 1 ^ ^82 S Be : CO t^ co ^ T-< Tt< IO I 00 QJ 1 00 O COt^CO Tfi M o o *o co o ^ co o co co o o o SK SS3S Sg OS i ( CO OO i-t t^ OSiOIXN rt< CO O i I CC O^ OO C1 1> O CO OO -l>-OOt>COO'OC^COcO' lOCOTt^COC^C^O" (NCOiOOi-HCOrHi-iOOt^COCOINOOCOCOCOt-O 1 ;iO^H -^i^OOOO ^H ^ O5 !> ^5 C^ 0^ ^D s OOi iCOiOiOt^TtloOCOt^t^OOI^iOCOOSOSOSO 1 OO OS OS OS OS 00 OS OS OS OS OS OS OS OS OS OS OS OS OC ;c^ ^o oo oo o^ c^ ^* "^ t>- iO OOOOOOOCO ::::: ; : : : : Location. : '. ' '. ' '. ' jv lii^d^i if L *> liJijfjJHl IMI ll Iril 3s 1 l-f-i s 1 > .2 03 I -'. o SANDSTONES 135 3 ^ OOOO rH rH i-H O O OOO rH CO t>- rH T^ IO 03 rH CO W II ai } OO -^ CO CO -CO Tt* -O O3 XOCOO5 -rH -o* -q -o rH rH (N O rH rH CO 'O 'O rH -CO OOO rHOOO'O' 'O'O O OrHOrHrH lO CO O O O CO b- Tt< !>. . . O O l>- COCO -CO O OS CO CO tO OSOO. CO *! rH rH O5 C.C^0 C Oi 00 00 t> Oi 1^- CO O^ O^ CO O^ 136 BUILDING STONES AND CLAYS (NO rH^H 'rH -00 OCOCOrH CO 10 O CO t>- C^ (N CO I-H lO r}^ O 00 ^H CO !N i i O O t^. i I do dddddddd ^ddddddd t^ . ^ ^. o "^ d i 1 ^ CO Oil>. lO O CO CO CO ^3 w cq T-* . (N o t^ 00 (N W t^ O O COO rH CO O i I O CO i-l CO "*! !> CO OO lO ^ O O CO 00 I> CO rH d . Suc Wil i ~ ^2 ^ 3 ifill 0.o - Wyoming SANDSTONES 137 TEXTURE AND PHYSICAL PROPERTIES. Shape and Size of Grain. The sedimentary siliceous rocks are given various names according to their texture. If the com- ponent grains are small and of fairly uniform size, the rock is properly a sandstone ; if the rock contains numerous rounded peb- bles, it is a conglomerate ; while if it is composed of large angular fragments, it is a breccia. Regarded as structural materials, how- ever, the sandstones proper demand most consideration, for conglomerates are rarely used for building purposes while breccias are still more rarely employed. Composition of the Cementing Material. The cementing material, as noted on a preceding page, may be quartz, clayey matter, iron oxide, or lime carbonate; and a descriptive adjective is frequently employed to describe these differences. When quartz or silica is the cement, the rock is a siliceous sandstone; while when iron oxide or lime carbonate bond the grains together the terms " ferruginous sandstone " and " calcareous sandstone " are respectively used. In some sandstones the cementing ma- terial is clayey or argillaceous. As regards the respective strength and durability of sandstones with different kinds of cementing material, other factors may vary so much that it is not safe to rely on any general rule. Other things being equal, however, the best cementing material is silica, followed by clay, iron oxide, and lime carbonate in the order named. The last is by far the worst. Value of Microscopic Work on Sandstones. When a thin section of sandstone is examined under the petrographic micro- scope, the investigator may hope to secure data covering the following points: (1) mineral character of the component grains; (2) size and shape of grains; (3) mineral character of cementing material; (4) relative proportion of cementing material to grains. In addition to these four points, all of which are usually readily determinable, it is sometimes possible to form some idea as to (5), the probable tenacity and durability of the cementing ma- terial. This fifth point is the one of greatest interest to the engineer, and if it were possible to express microscopic results on this point in some quantitative manner the trouble and expense of the investigation would be entirely justified. Even as it is, it will be safest to have the matter investigated in this way. For 138 BUILDING STONES AND CLAYS it must always be borne in mind, that in dealing with ordinary sandstones we are dealing with the weakest and most uncertain of all building stones, and that nothing should be overlooked which may throw light on the possible future behavior and durability of the particular sandstone which may be under examination. Physical Properties of Sandstones. In the following tables are presented the results of tests of strength, density, etc., on a large number of American and British sandstones. SANDSTONES 139 140 BUILDING STONES AND CLAYS 11 ii o> 11 oO CO o oo cco O O : c^f " ; co 1 ST ONES I rg > lO !> CO *"^ CO C^ CO CO CO i I 1>- I>-I>-COOCO i 1 XO CM i-H -^ II *!*> lO i i CM COt^COt^iO Compression. I si ! cTof ^T ! i^T ! *cf I li - - ; li jqCN CO O CO (M CM o *o *o t- oo -^ -coo o o - O -"5 -l^ t t>. . o -^ -r-i -g ^ ; ! ! oo ; *" (M . . .-* ."* i iS| i i . -o . .o ' ' -- .(MOO . . - O -*5 < >ot^ eo > iR" ic-^^ -or-oooot iOI>-C3 OCOOJCC-^i i ss" is** asi t 11 ll II 11 :>,-aa n& ' liiiii i-ebi318- J O ">> M 1 231?^ .sassg 148 BUILDING STONES AND CLAYS List of References on Sandstones. The following list covers the principal papers and reports dealing with the sandstones of the United States. Arkansas: Griswold, L. S. Whetstones and the novaculites of Arkansas. Ann. Rep. Ark. Geol. Sur. for 1890, Vol. 3, 443 pp. 1892. California: Jackson, A. W. Building stones (of California). 7th Ann. Rep. Cal. State Mineralogist, pp. 206-217. Anon. Sandstones of California. Bull. 38, Cal. State Min. Bureau, pp. 114-146. 1906. Indiana: Hopkins, T. C. The Carboniferous sandstones of western Indiana. 20th Ann. Rep. Indiana Dept. Geol., pp. 188-328. 1896. Also re- printed partly in Stone, Vol. 13, pp. 227-238, 334-342, 456-466. Abstracts also appeared in the Mineral Industry, Vol. 4, pp. 559-564 and in 17th Ann. Rep. U. S. Geol. Sur., pt. 3, pp. 780-787. Kindle, E. M. The whetstone and grindstone rocks of Indiana. 20th Ann. Rep. Indiana Dept. Geol., pp. 329-368. 1896. Iowa: Bain, H. F. Properties and tests of Iowa building stones. Rep. Iowa Geol. Sur., Vol. 8, pp. 370-416. 1898. Kansas: Bailey, E. H. S., and Case, E. C. On the composition of some Kansas building stones. Trans. Kan. Acad. Sci., Vol. 13, p. 78. Minnesota: Winchell, H. V. Minnesota Sandstones. Stone, Dec., 1896. . Minnesota quartzites. Stone, Vol. 14, pp. 122-125. 1897. Crider, A. F. The geology and mineral resources of Mississippi. Bull. 283, U. S. Geol. Sur. New Jersey: Kiimmel, H. B. The Newark system or red sandstone belt (of N. J.). Ann. Rep. N. J. State Geol. for 1898, pp. 23-159. 1898. New York: Bishop, I. P. Structural and economic geology of Erie County. 15th Ann. Rep. N. Y. State Geol., Vol. 1, pp. 305-392. 1897. Dickinson, H. T. Quarries of bluestone and other Devonian sandstones of New York State. Bull. 61, N. Y. State Museum, 112 pp. 1903. Eckel, E. C. The quarry industry in southeastern New York. 20th Ann. Rep. N. Y. State Geol., pp. 141-176. 1902. Gordon, J. B. The bluestone industry of New York. Stone, July, 1899. Ingram, H. B. The great bluestone industry. Popular Science Monthly, Vol. 45, pp. 352-359. 1894. SANDSTONES 149 Lincoln, D. F. Report on the structural and economic geology of Seneca County. 14th Ann. Rep. N. Y. State Geol., pp. 60-125. 1895. Smock, J. C. Building stone in the State of New York. Bull. 3, N. Y. State Museum, 152 pp. 1888. Smock, J. C. Building stone in New York. Bull. 10, N. Y. State Museum, 396 pp. 1890. Winchell, N. H. The Potsdam sandstone at Potsdam, N. Y. 21st Ann. Rep. Minn. Geol. Sur., pp. 99-111. 1893. Ohio: Orton, E. The Berea sandstone of Ohio. Rep. Ohio Sec. of State for 1878, pp. 591-599. 1879. Pennsylvania: Hopkins, T. C. The building materials of Pennsylvania: I, Brownstones. Appendix to Ann. Rep. Penn. State Coll. for 1896, 122 pp. 1897. Reprinted in part in 18th Ann. Rep. U. S. Geol. Sur., pt. 5, pp. 1025-1043. West Virginia: Grimsley, G. P. The sandstones of West Virginia. Bull. 4, W. Va., Geol. Sur., pp. 355-595. 1909. Wisconsin: Buckley, E. R. Building and ornamental stones of Wisconsin. Bull. 4, Wis. Geol. Sur., 500 pp. 1898. Wyoming: Knight, W. C. The building stones and clays of Wyoming. Eng. and Min. Jour., Vol. 66, pp. 546, 547. 1898. CHAPTER IX. LIMESTONES. THOUGH marbles are, from a strictly geological point of view, merely special varieties of limestone, they occupy so distinct a position in the stone trade as to require separate consideration. For this reason the two classes of stone will be treated in separate chapters in the present volume ; Chapter IX being devoted to the consideration of the ordinary structural limestones, while Chap- ter X will contain data on the marbles and decorative limestones. The origin of limestones in general will of course be discussed in the present chapter. ORIGIN AND CHEMICAL COMPOSITION. Origin of Limestones.* Limestones have been formed largely by the accumulation at the sea bottom of the calcareous remains of such organisms as the foraminifera, corals, and molluscs. Many of the thick and extensive limestone deposits of the United States were probably deep-sea deposits formed in this way. Some of these limestones still show the fossils of which they were formed, but in others all trace of organic origin has been destroyed by the fine grinding to which the shells and corals were subjected before their deposition at the sea bottom. It is probable also that part of the calcium carbonate of these lime- stones was a purely chemical deposit from solution, cementing the shell fragments together. A far less extensive class of limestones, though very important in the present connection, owe their origin to the indirect action of organisms. The " marls," which have until recently been so important as Portland-cement materials, fall in this class. As the class is of limited extent, and includes no products used in structural work, its method of origin may be dismissed here. Deposition from solution by purely chemical means has un- * For a more detailed discussion of this subject the reader will do well to consult Chapter VIII of Prof. J. F. Kemp's " Handbook of Rocks." 150 LIMESTONES 151 doubtedly given rise to numerous important limestone deposits. When this deposition took place in caverns or in the open air it gave rise to onyx deposits and to the " travertine marls" of cer- tain Ohio and other localities; when it took place in isolated por- tions of the sea, through the evaporation of the sea water, it gave rise to the limestone beds which so frequently accompany de- posits of salt and gypsum. Shells as Sources of Limestone.* Most molluscan shells con- sist essentially of lime carbonate, with commonly very small per- centages (less than 1 per cent) of magnesium carbonate, and traces of alkalies, phosphoric acid, etc. The analyses given in Table 78 will serve to illustrate the composition of the shells of three common species of molluscs. TABLE 78. ANALYSES OF VARIOUS MOLLUSCAN SHELLS. 2 3 4 5 6 Silica (SiO 2 ) 3.30 1.49 n.d. 0.20 0.16 n.d. Alumina (AUOi) 08 Iron oxide (Fe2O3) 17 04 nd. 04 Lime (CaO) 52 14 53 37 n.d. 52 86 54 55 54 38 Magnesia (MgO) 25 Alkalies (K 2 O, Na->O) 35 Sulphur trioxide (SO 3 ) 16 81 80 35 28 28 Phosphorus pentoxide (PzO^) Carbon dioxide (CO 2 ) Water n.d. 41.61 0.11 40.60 n.d. n.d. 0.05 41.02 0.001 42.82 n.d. n.d. Organic matter 2.32 3.48 3.17 5.02 2 01 2 04 1. Oyster shell; L. P. Brown and J. S. H. Koiner, analysts; American Chemical Journal, Vol. 11, pp. 36-37. 2, 3. Oyster shell; How, analyst; American Journal of Science, 2d series, Vol. 41, p. 380. 4. Mussel shell; How, analyst; American Journal of Science, 2d series, Vol. 41, p. 380. 5, 6. Periwinkle shell; How, analyst; American Journal of Science, 2d series, Vol. 41, pp. 379-381. These analyses show that in ordinary practice an oyster shell may be expected to contain, as its principal impurities, several * Brown, L. P., and Koiner, J. S. H. Analysis of oyster shells and oyster- shell lime. American Chemical Journal, Vol. 11, pp. 36, 37. 1889. How, Dr. On the comparative composition of some recent shells, a Silurian fossil shell, and a Carboniferous shell limestone. American Journal of Science 2d series, Vol. 41, pp. 379-384. 1866. 152 BUILDING STONES AND CLAYS per cent of organic matter and from a trace to 5 per cent of silica, iron oxide, and alumina. The amount of these last clayey im- purities present will doubtless vary with the cleanness of the shell, as it is probable that they are in large part purely external impurities. Chemical Composition of Limestone. Calcite, a rock-forming mineral in all limestones, is carbonate of lime. A theoretically pure limestone is merely a massive form of the mineral calcite. Such an ideal limestone would therefore consist entirely of calcium car- bonate or carbonate of lime, with the formula CaC0 3 (CaO+C0 2 ), corresponding to the composition calcium oxide (CaO) 56 per cent, carbon dioxide or carbonic acid (CO 2 ) 44 per cent. As might be expected, the limestones we have to deal with in practice depart more or less widely from this theoretical com- position. These departures from ideal purity may take place along either of two lines: a. The presence of magnesia in place of part of the lime; 6. The presence of silica, iron, alumina, alkalies, or other impurities. It seems advisable to discriminate between these two cases, even though a given sample of limestone may fall under both heads, and they will therefore be discussed separately. The Presence of Magnesia in Place of Part of the Lime. The theoretically pure limestones are, as above noted, composed entirely of calcium carbonate and correspond to the chemical formula CaCO 3 . Setting aside for the moment the question of the presence or absence of such impurities as iron, alumina, silica, etc., it may be said that lime is rarely the only base in a lime- stone. During or after the formation of the limestone a certain percentage of magnesia is usually introduced in place of part of the lime, thus giving a more or less magnesian limestone. In such magnesian limestones part of the calcium carbonate is replaced by magnesium carbonate (MgC0 3 ), the general formula for a magnesian limestone being, therefore, x CaCO 3 + y MgCO 3 . In this formula x may vary from 100 per cent to zero, while y will vary inversely from zero to 100 per cent. In the particular case of this replacement where the two carbonates are united in equal molecular proportions, the resultant rock is called dolo- LIMESTONES 153 mite. It has the formula CaCO 3 MgC0 3 , corresponding to the composition calcium carbonate 54.35 per cent, magnesium car- bonate 45.65 per cent. In the case where the calcium carbonate has been entirely replaced by magnesium carbonate, the result- ing pure carbonate of magnesia is called magnesite, having the formula MgC0 3 and the composition magnesia (MgO) 47.6 per cent, carbon dioxide (CO 2 ) 52.4 per cent. Rocks of this series may therefore vary in composition from pure calcite limestone at one end of the series to pure magnesite at the other. The term limestone has, however, been restricted in general use to that part of the series lying in composition be- tween calcite and dolomite, while all those more uncommon phases carrying more magnesium carbonate than the 45.65 per cent of dolomite are usually described simply as more or less impure magnesites. Though magnesia is often described as an " impurity " in limestone, this word, as can be seen from the preceding state- ments, hardly expresses the facts in the case. The magnesium carbonate present, whatever its amount, simply serves to replace an equivalent amount of calcium carbonate, and the resulting rock, whether little or much magnesia is present, is still a pure carbonate rock. With the impurities to be discussed in later paragraphs, however, this is not the case. Silica, alumina, iron, sulphur, alkalies, etc., when present are actual impurities, not merely chemical replacements of part of the calcium carbonate. The Presence of Silica, Alumina, Iron, and Other Impurities. If a number of limestone analyses be examined, it will be found that the principal impurities present are silica, alumina, iron oxide, sulphur, and alkalies. Silica when present in a marble or crystalline limestone is usually combined with alumina, iron, lime, or magnesia, and occurs therefore in the form of a silicate mineral. In an ordinary limestone it is very often present as masses or nodules of chert or flint, or else combined with alumina as clayey matter. In the softer limestones, such as the chalks and marls, the silica may be present as grains of sand. Alumina is commonly present combined with silica either as grains of a silicate mineral or as clayey matter. Iron may be present as carbonate, as oxide, or in the sulphide form as the mineral pyrite. 154 BUILDING STONES AND CLAYS Sulphur is commonly present in small percentages in one of two forms: as pyrite or iron disulphide (FeS 2 ) or as gypsum or lime sulphate (CaS0 4 + 2 H 2 O). The alkalies soda and potash are frequently present in small quantity, probably in the form of carbonates. Average Composition of Limestones. On succeeding pages a series of tables containing a large number of analyses of Ameri- can limestones of commercial importance will be presented. Be- fore doing this, however, it is of interest to endeavor to get some idea of the normal or average chemical composition of the stones of this group. Fortunately a very interesting pair of average analyses are available for this purpose, and these are reprinted here as Table 79. TABLE 79. AVERAGE ANALYSES OF AMERICAN LIMESTONES. (F. W. CLARKE.) A. B. Silica (SiO 2 ) 5.19 14.09 Alumina (A1 2 O 3 ) * 0.87 1.83 Iron oxide (Fe 2 Os) 0.54 0.77 Lime (CaO) 42.61 40.60 7.90 4.49 Soda (Na 2 O) 0.05 0.62 Potash (K 2 O) 0.33 0.58 Phosphorus pentoxide (P 2 O5) 0.04 0.42 Sulphur (S) 0.09 0.07 Sulphur trioxide (SOs) 0.05 0.07 41.58 35.58 0.56 0.88 0.21 0.30 * Including very small amounts of titanic oxide (TiO 2 ). f Including organic matter. A. Composite analyses of 345 samples of American limestones, uses not specified. H. N. Stokes, analyst. B. Composite analyses of 498 samples of American limestones used for building purposes. H. N. Stokes, analyst. LIMESTONES 155 TABLE 80.* ANALYSES OF LIMESTONES: (BEDFORD STONE.) INDIANA. Locality. Silica. Alumina and Iron. Lime car- bonate. Magnesium carbonate. Alkalies. Water. Bedford 64 0.15 98.27 0.84 Bedford 0.50 0.98 96.60 0.27 0.40 0.61 Bedford 0.63 0.39 98.20 0.39 Bedford 1.69 0.49 96.79 0.23 0.32 0.41 Big Creek 15 64 93 80 4 01 1 09 Big Creek 50 71 93 07 4 22 1 19 Bloomington 1 74 29 95 62 89 59 Bloomington 1 60 18 95 55 93 42 Bloomington 65 1.00 95.54 0.40 0.55 0.25 Harrison County Hunter Valley 0.31 86 0.32 16 98.09 98 11 n.d. 92 0.40 0.12 Romona 1 26 18 97 90 0.65 Salem 1.13 1.06 96.04 0.72 0.15 0.10 Spencer 0.70 0.91 96.79 0.23 0.32 0.41 Stinesvile 90 3 00 95.00 0.22 0.83 0.05 Twin Creek 76 15 98 16 97 * 21st Ann. Rep. Ind. Dept. Geol., p. 320. TABLE 81.* ANALYSES OF LIMESTONES: MISSOURI. Locality. Silica. Alu- mina and iron oxides. Lime carbon- ate. Lime. Magne- sium carbon- ate. Magne- sia. Carbon dioxide. Water. Bowling Green 13 99 1 62 49 77 34 46 Breckenridge .... 2 93 54 54 22 22 42 58 Cape Girardeau 0.10 14 55 73 24 43 91 27 Cape Girardeau Carthage 2.93 0.69 0.45 0.21 87.23 98.57 9.26 65 De Soto 11.19 0.68 48.18 39.99 Hannibal 26 14 98 87 62 Jackson 4 66 28 52 29 97 41 72 Osceola 99 17 98 59 09 Phenix 21 23 99 06 58 Princeton 1 88 78 96 22 1 01 Republic Sedalia 0.45 17.69 0.12 1 08 49 21 55.48 3i 57 0.03 43.70 0.42 Springfield 36 13 99 34 22 Springfield 4.51 0.52 92.24 2.35 St. Louis. . . 54 25 55 42 25 43 42 St. Louis 2 36 27 96 09 90 Kept. Mo. Bur. Geol., Vol. 2, 2d series, p. 308. 156 BUILDING STONES AND CLAYS TABLE 82. ANALYSES OF LIMESTONE: WISCONSIN. 1 2 3 4 5 6 Silica 3 17 6 32 02 2 12 1 09 61 Alumina ) 1 95 1 02 01 59 33 (1.97 Ferric oxide ) Ferrous oxide \ 2.18* Lime carbonate 49 97 50.96 54 74 53 51 54 42 52 48 Magnesium carbonate 44 58 41.75 45 07 43 54 44 17 41 94 * Fe 2 C0 3 . 1. Duck Creek; W. W. Daniells, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 2. Genesee; W. W. Daniells, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 3. Knowles; W. W. DanieUs, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 4. Marblehead; W. W. Daniells, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 5. Sturgeon Bay; W. W. Daniells, analyst; Bull. 4, Wis. Geol. Sur., p. 420. 6. Washburn, Bayfield County; C. W. Hall, analyst; Min. Res. U. S., 1903, p. 205. PHYSICAL CHARACTERS AND TESTS. Texture and Structure. In texture limestones differ among themselves even more widely than do sandstones, for in addition to differences in size and shape of grain, there are also important structural differences to be considered. Many of these points of difference between individual limestones are obvious enough when a hand specimen is examined, but occasionally differences are only brought to notice by the microscope. This last case is relatively rare, however, and the examination of thin sections of limestone under the petrographic microscope does not often yield enough information to justify the trouble and expense. Color. Limestones when absolutely pure are white, but as actually found in nature they show a wide range of colors from pure white through yellowish, bluish, and gray tints to deep black. Pink, reddish, and green limestones also occur, but in these cases the limestone is usually polished and marketed as a marble. The commonest tints are, however, light gray and grayish-blue. These variations in color are due to the character and amount of impurities present, the principal coloring agents being organic matter and iron oxide. The color, whatever its tint, may be uniformly distributed throughout the stone, or it may show blotching or banding with LIMESTONES 157 two or more tints. Such irregular distribution of color is un- desirable in an ordinary limestone ; but if the colors show pleasing contrasts, and the texture of the stone admits of a good polish, the material may be valuable as a decorative marble. Varieties of Limestone. A number of terms are in general use for the different varieties of limestone, based upon differences of origin, texture, composition, etc. The more important of these terms will be briefly defined. The marbles are limestones which, through the action of heat and pressure, have become more or less distinctly crystalline. The term marl as at present used in cement manufacture is ap- plied to a loosely cemented mass of lime carbonate formed in lake basins. Calcareous tufa and travertine are more or less compact limestones deposited by spring or stream waters along their courses. Oolitic limestones, so called because of their resemblance to a mass of fish-roe, are made up of small rounded grains of lime carbonate. Chalk is a fine-grained limestone composed of finely comminuted shells, particularly those of the foraminifera. The presence of much silica gives rise to a siliceous or cherty limestone. If the silica present is in combination with alumina, the resulting limestone will be clayey or argillaceous. Physical Characters of Limestones. In texture, hardness, and compactness the limestones vary from the loosely consoli- dated marls through the chalks to the hard, compact limestones and marbles. Parallel with these variations are variations in absorptive properties and density. The chalky limestones may run as low in specific gravity as 1.85, corresponding to a weight of, say, 110 pounds per cubic foot, while the compact limestones commonly used for building purposes range in specific gravity between 2.3 and 2.9, corresponding approximately to a range in weight of from 140 to 185 pounds per cubic foot. TABLE 83. COMPRESSIVE STRENGTH OF AMERICAN LIMESTONES. State. Locality. Tested by "3 6 fc Size of cube. Compressive strength, pounds per square inch. Min. Aver. Max. Arkansas Illinois Indiana Kentucky Missouri New York Texas Wisconsin Eureka Springs, Carroll Co. Beaver, Carroll Co Watertown Arsenal Navy Department Ark. Indust. Inst. Univ. Illinois Watertown Arsenal Rose Polytech. Inst. Watertown Arsenal Missouri Geol. Sur. Watertown Arsenal Rock Island Arsenal Un v. of Texas Wisconsin Geol. Sur. Univ. of Wisconsin Wisconsin Geol. Sur. In. 21,397 20,581 15,550 13,544 14 120 Johnson, Carroll Co Kankakee, Kankakee Co. . . Niota, Hancock Co Ellettsville Salem "3' 3 3 3 3 3 3 3 3 3 3 3 3 6 4 11 3 2 2 4 10 2 5 7 7 4 4 4 4 6 4 6 4 4 3 2 7 2 "f 4 4 4 5 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5,900 5,900 8,400 3,400 6,400 6,900 11,700 11,400 4,600 7,800 Bloomington Hunter Valley Romona Bedford 3,400 3,300 6,400 4,400 4,700 4,500 5,800 4,100 6,532 5,656 13,660 6,800 4,800 9,700 6,900 8,200 7,500 6,200 6,600 7,009 ",425 17,130 20,261 10,721 8,267 10,290 18,575 10,679 29,306 14,102 19,751 12,582 12,544 13,124 12,985 25,360 14,176 13,013 12,704 10,071 14,053 13,140 22,438 17,149 28,951 Stinesville. . 6,035 5,635 6,762 6,692 14,947 15,282 8,792 6,944 9,829 15,980 9,214 27,813 11,870 16,319 11,545 11,260 11,198 12,641 24,662 12,062 11,270 8,705 8,486 12,995 10,453 20,779 15,063 23,724 3,422 Bowling Green, Warren Co. . Caden, Warren Co Carthage Bowling Green Breckenridge Columbia De Soto Hannibal . . . Joplin . Jefferson City . Kahoka Koeltztown Noel . . Phenix Pierce City Rolla Sedalia . . Sheffield Springfield St Louis 18,496 Buffalo Duval 8207 2,279 6,303 14,950 18,660 9,228 2,300 1,495 3,180 "20,326' 12,255 4 4 1 1 1 1 .... 1 1 "2 "2 9 14,545' 7,305 Honey Creek, Burnet Co.. . . Slaughter Creek . Bear Creek Cedar Park Round Rock Lueders, Jones Co 6,675 ' 23,783' 2,487 8,394 12,066 24,283 8,830 36,731 29,189 10,112 "24,783' Duck Creek Genesee Knowles "e" ' '29,526' 31,936 42,787 30,941 19,234 18,379 ' 31,957' "w.iii" Myrblehead Waukesha Wauwatosa 17,647 (158) LIMESTONES 159 TABLE 84. PHYSICAL TESTS OF LIMESTONES: ENGLAND. (BEARI.) Locality. Specific gravity. Weight per cubic foot. Absorption, per cent. Compressive strength, pounds per square inch. White Man's Field 2 245 140.1 5.01 7,185 Red Man's Field 2.295 143.2 4.58 9,210 Yellow Man's Field 2.33 145.4 4.62 8,980 Anston 2.117 - 132.2 7.50 4,700 Ancaster (2.25 140.4 6.27 2,860 Portland . ... | 2.505 (2.205 < 1 . 995 156.3 137.6 124 5 2.42 6.84 11.10 8,595 4,465 2,285 Ketton ( 2.120 2.05 132.3 127.9 7.51 8.10 3,190 1,585 D 2 80 174 7 14875 Corsham Down 2.067 129.0 11.12 1,705 Farleigh Down 1.93 120.5 12.88 1,010 Monks Park 2 19 136 7 8 03 2,255 Box Ground.. . 2 05 127 9 7 79 1,515 Coombe Down 2 06 128 6 5 99 2,005 Corngrit 2 14 133 6 8 88 2,185 Stoke Ground 2.023 126 3 10 85 1,540 Winsley Ground 2.13 132 9 7 74 1,660 Westwood Ground (2.12 132.3 8.03 1,735 Doulting . . ( 2.087 ( 2.41 130.3 150.4 8.85 3.36 1,910 2,815 Ham Hill I 2.003 2 18 125.0 136 10.87 ? 1,735 2 585 DISTRIBUTION AND PRODUCTION. Geologic and Geographic Distribution of Limestones. Lime- stones occur in every state and territory in the United States, though of course some states (Delaware, North Dakota, Louisi- ana, etc.) are so poorly supplied that they can never become important lime producers, while other states are almost entirely underlain by limestone strata. Geologically, the limestone utilized in various parts of the United States ranges entirely through the geological column, from the pre-Cambrian to the Pleistocene, inclusive. Under such conditions of wide geographic and geologic distri- bution it is not practicable to give a summary of any value in the present volume. The list of references given in the follow- ing pages will enable the reader to ascertain the facts regarding the limestones of any given state in which he may be interested. 160 BUILDING STONES AND CLAYS Reference List for Limestones: Alabama: McCalley, H. The fluxing rocks of Alabama. Eng. and Min. Journal, vol. 63, pp. 115, 116. 1897. Meissner, C. A. Analyses of limestones and dolomites of the Birmingham district. Proc. Alabama Industrial and Scientific Society, vol. 4, pp. 12-23. 1894. California: Jackson, A. W. Building stones of California. 7th Annual Report California State Mineralogist, pp. 206-217. 1888. Colorado: Lakes, A. Building and monumental stones of Colorado. Mines and Minerals, vol. 22, pp. 29, 30. 1901. Lakes, A. Sedimentary building-stones of Colorado. Mines and Minerals, vol. 22, pp. 62-64. 1901. Connecticut: Ries, H. The limestone quarries of eastern New York, western Vermont, Massachusetts, and Connecticut. 17th Ann. Report U. S. Geological Survey, pt. 3, pp. 795-811. 1896. Georgia: McCallie, S. W. A preliminary report on the marbles of Georgia. Bull. No. 1, Georgia Geological Survey, 92 pp. 1894. Indiana: Foerste, A. F. A report on the Niagara limestone quarries of Decatur, Franklin, and Fayette counties. 22d Ann. Rep. Indiana Dept. Geology and Natural Resources, pp. 195-255. 1898. Hopkins, T. C., and Siebenthal, C. E. The Bedford oolitic limestone of Indiana. 21st Ann. Rep. Indiana Dept. Geology and Natural Resources, pp. 291-427. 1897. Iowa: Bain, H. F. Properties and tests of Iowa building-stones. Reports Iowa Geological Survey, Vol. 8, pp. 367-416. 1898. Houser, G. L. Some lime-burning dolomites and dolomitic building stones from the Niagara of Iowa. Reports Iowa Geological Survey, Vol. 1, pp. 199-207. 1892. Bailey, E. H. S., and Case, E. C. On the composition of some Kansas building-stones. Trans. Kansas Academy Science, vol. 13, p. 78. Kentucky: Crump, H. M. The clays and building stones of Kentucky. Eng. and Mining Journal, vol. 66, pp. 190, 191. Aug. 13, 1898. Maryland: Matthews. An account of the character and distribution of Maryland building stones, together with a history of the quarrying industry. Reports Maryland Geological Survey, Vol. 2, pp. 125-241. 1898. Massachusetts: Ries, H. The limestone quarries of eastern New York, western Vermont, Massachusetts, and Connecticut. 17th Ann. Rep. U. S. Geol. Survey, pt. 3, pp. 795-811. 1896. LIMESTONES 161 Michigan: Benedict, A. C. The Bayport (Mich.) quarries. Stone, vol. 17, pp. 153-164. 1898. Grabau, A. W. Stratigraphy of the Traverse group of Michigan. Ann. Report Michigan Geological Survey for 1901, pp. 161-210. 1902. Lane, A. C. Michigan limestones and their uses. Eng. and Mining Journal, vol. 71, pp. 662, 663, 693, 694, 725. 1901. Lane, A. C. Limestones (of Michigan). Ann. Rep. Mich. Geol. Survey for 1901, pp. 139-160. 1902. Lane, A. C. Limestones (of Michigan). Ann. Rep. Mich. Geol. Survey for 1902, pp. 17-19. 1903. Minnesota: Winchell, N. H. The building stones of Minnesota. Final Report Geology of Minnesota, Vol. 1, pp. 142-204. 1884. Missouri: Buckley, E. R. Quarry industry of Missouri. Bull. 2, Missouri Geo- logical Survey, 1904. Nebraska: Fisher, C. A. Directory of the limestone quarries of Nebraska. Ann. Rep. for 1901, Nebraska State Board of Agriculture, pp. 243-247. 1902. New Jersey: Cook, G. H., and Smock, J. C. New Jersey building stones. Reports 10th Census, Vol. 10, pp. 139-146. 1884. Nason, F. L. The chemical composition of some of the white limestones of Sussex County, New Jersey. American Geologist, vol. 13, pp. 154-164. 1894. New York: Bishop, I. P. Structural and economic geology of Erie County, N. Y. 15th Ann. Rep. N. Y. State Geologist, vol. 1, pp. 305-392. 1897. Eckel, E. C. The quarry industry in southeastern New York. 20th Ann. Rep. N. Y. State Geologist, pp. 141-176. 1902. Lincoln, D. F. Report on the structural and economic geology of Seneca County, N. Y. 14th Ann. Rep. New York State Geologist, pp. 60-125. 1897. Ries, H. The limestone quarries of eastern New York, western Vermont, Massachusetts, and Connecticut. 17th Ann. Rep. U. S. Geological Survey, pt. 3, pp. 795-811. 1896. Ries, H. Limestones of New York and their economic uses. 17th Ann. Rep. N. Y. State Geologist, pp. 355-468. 1899. Ries, H. Lime and cement industries of New York. Bull. 44, N. Y. State Museum. 1903. Smock, J. C. Building stones in the state of New York. Bull. 3, N. Y. State Museum, 152 pp. 1888. Smock, J. C. Building stones in New York. Bull. 10, N. Y. State Museum, 396 pp. 1890. Oklahoma: Gould, C. N. Oklahoma limestones. Stone, vol. 23, pp. 351-354. 1901. 162 BUILDING STONES AND CLAYS Pennsylvania: Frear, W. The use of lime on Pennsylvania soils. Bull. 61, Penna. Dept. Agriculture, 170 pp. 1900. South Dakota: Todd, J. E. The clay and stone resources of South Dakota, Eng. and Mining Journal, vol. 66, p. 371. 1898. Tennessee: Cotton, H. E., and Gattinger, A. Tennessee building stones. Reports Tenth Census, Vol. 10, pp. 187, 188. 1884. Keith, H. Tennessee marble. Bull. 213, U. S. Geol. Survey, pp. 366- 370. 1903. Texas: Durable, E. T. Building and ornamental stones of Texas. Stone, May, 1900. Vermont: Perkins, G. H. Report on the marble, slate, and granite industries of Vermont. 68 pp. Rutland, 1898. Perkins, G. H. Limestone and marble in Vermont. Rep. Vermont State Geologist for 1899-1900, pp. 30-57. 1900. Ries, H. The limestone quarries of eastern New York, western Vermont, Massachusetts, and Connecticut. 17th Ann. Rep. U. S. Geol. Survey, pt. 3, pp. 795-811. 1896. Wisconsin: Buckley, E. R. Building and ornamental stones of Wisconsin. Bull. 4, Wisconsin Geol. Survey, 500 pp. 1898. Wyoming: Knight, W. C. The building-stones and clays of Wyoming. Eng. and Mining Journal, vol. 66, pp. 546, 547. 1898. Production of Limestone in the United States. The follow- ing tables, quoted from those annually published by the United States Geological Survey, contain statistics on the American limestone industries for a series of years. TABLE 85. LIMESTONE PRODUCTION OF THE UNITED STATES, 1899-1909. Year. Value. Year. Value. 1899 $13,889,302 1905 $26,025,210 1900 13,556,523 1906 27,327,142 1901 18,202,843 1907 31,737,631 1902 20,895,385 1908 27,682,002 1903 22,372,109 1909 32,070,401 1904 22,178,964 1910 34,603,678 LIMESTONES 163 TABLE 86. LIMESTONE PRODUCTION, BY STATES, 1905-1909. State or Territory. 1905. 1906. 1907. 1908. 1909. Alabama $532,103 $579,344 $694,699 $479,730 $700,642 Arizona 135 40 64,975 a 50,130 (b) Arkansas California 154,818 49,902 48,844 80,205 52,207 177,333 61,971 237,320 112,468 283,869 Colorado Connecticut 289,920 1,558 373,158 1,171 502,751 1,476 378,822 c 3,727 355,136 c 5,023 Florida 5,800 1,450 15,000 41,910 d 49,856 Georgia Hawaii 9,030 16,042 22,278 8,495 34,593 (e) Idaho 14,105 12,600 15,900 36,000 (e) Illinois Indiana 3,511,890 3,189,259 2,942,331 3,725,565 3,774,346 3,624,126 3,122,552 3,643,261 4,234,927 3,749,239 Iowa Kansas 451,791 923,389 493,815 849,203 560,582 813,748 530,945 403,176 525,277 892 335 Kentucky 744,465 795,408 891,500 810,190 903,874 Louisiana . . . ... (/) Maine 7,428 2,000 1,350 (g) (g) Maryland Massachusetts 149,402 65,908 170,046 10,750 142,825 1 837 128,591 1 950 197,939 Michigan 544,754 656,269 760,333 669,017 750,589 Minnesota 555,401 632,115 735,319 667 095 698 309 Missouri 2 238 164 1 988 334 2 153 917 2 130 136 2 111 283 Montana Nebraska 103,123 225 119 141,082 276 381 124,690 312 630 134,595 330 570 154,064 293 830 New Jersey New Mexico . . . 147,353 7,200 221,141 125,493 274,452 193 732 172,000 (A) 224,017 t 140 801 New York 1,970,968 2,204,724 2,898,520 2,584,559 2,622,353 North Carolina. . . 16,500 30,583 22,328 0) 0') Ohio . 2 850 793 3 025 038 3 566 822 3 519 557 4 020 046 Oklahoma 168,924 171,983 189,568 257 066 450 055 Oregon 8,600 7480 5 750 6 230 Pennsylvania 4 499 503 4 865 130 5 821 275 4 057 471 5 073 825 Rhode Island 300 678 750 (g) (g) South Dakota 6 653 10 400 11 600 (k) I 49 328 Tennessee 401,622 481,952 385 450 m 535 882 m 589 949 Texas. . . 171 847 239 125 267 757 314 571 341 528 Utah 232 519 248 868 306 344 253 088 169 700 Vermont Virginia 11,095 212 660 14,728 260 343 23,126 362 062 20,731 280 542 18,839 342 656 Washington 52,470 49,192 62317 31 660 38 269 West Virginia.... 671 318 628 602 855 941 645 385 864 392 Wisconsin 804 081 891 746 1 027 095 1 102 009 1 047 044 Wyoming 23,340 53 783 18 920 n 31 168 24 346 Total 26,025,210 27,327,142 31,737,631 27,682,002 32,070,401 a Includes New Mexico. 6 Included in New Mexico. c Includes Maine and Rhode Island. d Includes Louisiana. e Included in South Dakota. / Included in Florida. Included with Connecticut. h Included with Arizona. i Includes Arizona. j Included with Tennessee, ik Included with Wyoming. I Includes Hawaii and Idaho. m Includes North Carolina, n Includes South Dakota. 164 BUILDING STONES AND CLAYS TABLE 87. LIMESTONE PRODUCTION, BY STATES AND USES, 1909. State or Territory. Rough building. Dressed building. Paving. Curbing. Flagging. Rubble. Riprap. Alabama $775 $27 197 $2 000 $46 115 $8 460 $19 200 Arkansas 23,655 74,413 650 California 12,341 Connecticut 90 Florida 6,955 684 14,400 Georgia 954 Illinois Indiana Iowa 62,395 1,235,524 41,866 34,323 1,353,180 7,765 2,600 534 4,348 109,454 420 $4,651 4,921 368,605 14,100 49,947 115,413 7,939 43,094 Kansas .' Kentucky 75,574 130,784 43,775 63,844 22,044 4,583 160 16 313 493 219 58,519 6 596 41,984 20,081 Maryland Michigan 4,413 4,450 7,445 600 10 1,572 1,500 3,615 Minnesota 169,929 96809 5 697 5 031 94453 42 666 Missouri 233,215 408,327 1,531 2,354 10,374 301,463 106,419 Montana 7,628 333 Nebraska 1,507 1,033 12,926 28,645 New Jersey 375 540 New York 168,569 37,355 3,080 2,574 315 83,198 63,526 Ohio Oklahoma 102,109 4,850 31,133 1,000 624 180 27,675 4,459 430,789 35,889 Pennsylvania 104,930 1,410 124,521 2,128 1,250 2,283 709 Tennessee 16,854 4,432 3,310 4,085 26,298 Texas 28,601 17540 365 60 86,241 14,581 Utah 29 785 Vermont 5,412 Virginia Wisconsin 715 96,161 129 15,832 15 26,807 20,573 7 13,902 3,000 97,689 ""65,063' Wyoming 700 Total 2,570,326 2,226,942 188,680 214,140 41,343 1,228,445 1,082,234 LIMESTONES 165 is TABLE 87. LIMESTONE PRODUCTION, BY STATES AND USES, 1909. Continued. State or Territory. Crushed stone. Flux. Sugar, factories. Other. Total. Road making. Railroad ballast. Concrete. Alabama $60,452 $5,521 $16,825 $512,585 $1,512 $700,642 (a) 112,468 283,869 355,136 6 5,023 c 49,856 34,593 (d) w 4,234,927 3,749,239 525,277 892,335 903,874 (e) CO 197,939 750,589 698,309 2,111,283 154,064 293,830 224,017 g 140,801 2,622,353 w 4,020,046 450,055 5,073,825 (/) t 49,328 j 589,949 341,528 169,700 18,839 342,656 38,269 864,392 1,047,044 24,346 Arkansas California 9,126 138,962 100 340 4,284 4,554 29,904 267,806 1,933 "'15,696' $92,233 86,888 5,875 342 3,000 8,755 Connecticut . . Florida Georgia Hawaii 4,150 749 2,569 14,091 12,343 3,103 Idaho Illinois 1,216,759 627,289 116,246 155,294 273,411 422,859 54,086 16,329 257,654 291,266 1,249,783 54,449 246,054 207,405 47,364 714,631 190,809 1,971 982 675 36,589 95,972 2,881 28,940 38,609 Indiana Iowa Kansas 493 10,804 Kentucky Louisiana Maine Maryland Michigan 108,630 132,902 80,441 542,904 "'83,i47' 8,321 3,750 750,980 '1,502,483" 5,491 596,023 20,071 42,445 38,329 87,445 '"31,898 61,201 112,829 157,263 339,036 15,400 118,523 8,346 3,150 495,970 "236,6i9' 243,277 489,241 "5',406' 72,706 24,260 '"'oi'.ois' ""31,675 127,532 15,000 206,435 15,395 343,891 '1,130,682' 3,165,872' "i',266' 87,432 40,819 126,915 250 213,444 31,317 492,497 56,075 ""25,845' 6,033 13,321 3,171 1,136 1,514 327,571 1,658 33,819 '"i5 "ii',606 253,406 Minnesota Missouri Montana Nebraska New Jersey New Mexico 107,500 419,489 "332,569' 148,589 444,091 New York North Carolina Ohio 2,088 223,695 6,500 140,767 Oklahoma Pennsylvania Rhode Island '22,944' South Dakota Tennessee 7,184 276,945 125,661 12,600 95,665 3,400 2,222 Texas Utah 13,000 "'143' 1,319 6,727 9,940 7,021 2,646 Vermont Virginia 8,672 31,076 225 47,152 379,723 '"84,883" "294, 938' 79,803 4,362 8,068 "19,865' 188,395 Washington. West Virginia Wisconsin ""2l',666' Wyoming Total 7,294,248 3,308,430 4,450,075 7,921,807 291,287 1,252,444 32,070,401 a Included in New Mexico. b Includes Maine and Rhode Island. c Includes Louisiana. d Included in South Dakota. e Included in Florida. / Included in Connecticut. g Includes Arizona. h Included in Tennessee. i Includes Idaho and Hawaii. 3 Includes North Carolina. CHAPTER X. MARBLES. THE term marble is applied by the geologist to limestones which, through the action of heat and pressure, have so changed in texture as to be completely crystalline, n In the stone trade, \ however, marble has a wider meaning, including any limestone which can be made to take a high polish and which, when so polished, will show pleasing color effects. Indeed the term has at times been carelessly applied even to siliceous rocks, a mis- application which entirely robs it of meaning. Varieties of Marble. Using the term marble in the sense in which it is applied by the engineer and quarryman, three quite distinct types may be noted. (a) Highly crystalline marbles showing distinct crystalline structure and fracture. These are usually white, though gray, black, or other markings may be present, scattered over a white ground. Most of the Alabama, Georgia, Vermont, Massachusetts, Connecticut, and southeastern New York marbles are of this type. (b) Subcrystalline or fossiliferous marbles; in which crystalline structure is rarely very noticeable, the value depending rather on color effect than on texture. Frequently these color effects are gained through the presence of fossils, as often shown in the Tennessee marbles. (c) Onyx marbles; translucent rocks, showing color banding, due to the fact that they were formed layer after layer by chemi- cal deposition from spring or cave waters. I. HIGHLY CRYSTALLINE MARBLES. In a sense, practically all limestones are crystalline, for under the microscope traces at least of crystalline structure can be detected even in the most earthy limestones. But the stones which are here grouped as the highly crystalline marbles are crystalline in a much greater degree, for they are made up entirely of grains of calcite or more rarely dolomite, and the crystalline 166 MARBLES 167 character of these component grains is obvious, even without the use of the microscope. Origin and Character. The present highly crystalline con- dition of these marbles is not due to anything in their chemical composition, or to the conditions under which they were origi- nally deposited, but to the effects of the heat and pressure to which they have been subjected since deposition. Originally they were simply limestones of quite ordinary type so far as either composition or structure were concerned, and under normal conditions they would have remained ordinary limestones to this day. If limestones are heated sufficiently under atmospheric pres- sure, they will simply be calcined, carbon dioxide being driven off and quicklime remaining. But if the heat be accompanied by intense pressure, sufficient to prevent the evolution of the carbon dioxide gas, the stone will assume a semifluid condition. This condition permits a gradual movement, rearrangement, and recrystallization of the particles of calcite; and if this meta- morphism is thorough enough, the final result is the production of a highly crystalline marble. On a later page in discussing the geological distribution of the highly crystalline marbles, some consideration will be given to the geological conditions which in certain parts of the coun- try favored the formation of these rocks in the fashion above described. Chemical Composition. Since the crystalline marbles are merely ordinary limestones physically altered by the action of heat and pressure, they may naturally be expected to show the same range in composition as would a series of normal limestones. If we could make an average analysis of all the crystalline lime- stones of the country, and compare this with an average analysis of all the unaltered limestones, this expectation would undoubt- edly be verified. The actual requirements of the stone trade, however, introduce conditions which interfere with this exact agreement in composi- tion of the two groups, as we find them in the market. This is due to the fact that the more impure crystalline marbles, formed by the alteration of siliceous and clayey limestones, are rarely suitable for dressing and polishing. The silica and clay of the original limestone have often, during the metamorphism, com- 168 BUILDING STONES AND CLAYS bined with some of the lime to form silicate minerals, and the irregular distribution of these minerals through the marble inter- feres with its dressing and decreases the attractiveness of its appearance. The result of this condition is that the highly crystalline marbles which have attained success in the market are rarely very impure. A series of marble analyses, therefore, tends to give a higher average lime content than does a series of analyses of ordinary limestones. MARBLES 169 Carbon dioxide CO CO CO 00 Oi CO *O O5 CO O i 1 "* O O (N t^ -^ CD CD O C i I CO CD OO O CO 00 O CO 00 OO CO CD ^^oojHjHO,-; ooodoi So CO I-H O CO O5 - OOCOOOOOO ^TtitoCNT-iOT-Hi i - 00 OS OiO5 O5 OOPOOOOOCOO Or- a 8 : S O O OO(N rH O O 1-1 ^ T-H O iOO(M(Nt-iO te >> i s ( t>* 'o ^^ o- . J O 170 BUILDING STONES AND CLAYS PQ r , _ 10 -oo 8 : : O 5 o -H -q St^2 co oo 05 oo o co .... . . .-^ . j 22;i2 O5O5-O5O5 tOO5 .... ...O'''O5 O5O5O5 lf}r-t j-< CJCX) Tf i o i i i ^ 3= d ^ I C 3 S^ Q MARBLES 171 CO ^ (N CO Oi O CO OO i I O OO O Tt< O5 O5 CO OOOOOOIO OrH^Hr-l rH O "O COCOiOCOOOOO rJH OO t^ Oi 00 00 C<1 t^ O3 00 O5 Oi CO 10 i-( -i>. 10 iO O O i i O CO 03 O OCO O O CO 1-1 O O 172 BUILDING STONES AND CLAYS s COCO ^H i-l (M ^^ CO lOr=H^Tj<W CO'CO'CD^OO" C^^t^^HC^ ^^(M^H 8^ DH O(M O co'ofo'o'cD" c C^ CO O CO CO CO CO Ob oo co CD CD CD CD co i i oo oo (N O5 C5> T-t l>-cocot^ CO O i i CO l>-l>.t^.l>. J OJ g 02 g 14^1 j s | ss s o - i I o^ ^ ^ MARBLES 173 T-H >O i 1 01 !> as ^5 ^^ CO ^^ i-H O OO CO (M co"o~o~ r^ GO" co i-Tio'Go'c'oWi-H O5 CO t^ CO O cOcot CO CQ C<1 rM> O O O5 O 00 CO CO 00 >O O5 t^T-HTtl CO001>- * oco tocoeoi- CN ^T" I>* l> T I > T-H t^ !> t^ OO OO OO OO OO OO -The result of the division of the subject between geologists and engineers has been that little attempt to secure uniformity of methods has been made by- any of the engineering societies which alone are strong enough to carry out such an attempt. This unsatisfactory condition, which prevents comparison of the results obtained in different laboratories, is due in large part to the complexity of the subject, and in so far can be obviated only by further work. It is due in part, however, to the con- ditions under which previous investigations have been carried 1 on, and to better these united effort is essential. / It would appear desirable that this subject be taken up by one or more of the American engineering societies, which alone possess sufficient influence to make any proposed series of tests the standard. In one way, indeed, it will be easier to secure uniformity in this branch of investigation, for testing machines capable of handling a stone cube are much fewer in number than are the smaller machines used for testing cements. Data Required from Tests. The points which an engineer 'or architect desires to know concerning any building stone are two in number: (1) Is the stone strong enough for the use to which it is to be put? (2) Will the stone retain its strength, structure, and color after exposure for a long series of years to the natural and arti- ficial agencies which may be expected to attack it? The two prime requisites of a building stone are, therefore, strength and durability; and most of the different tests which will be discussed in the present chapter have been devised merely to determine one of these two points, either directly or indirectly. This fact is sometimes lost sight of by the experimenter who, in LABORATORY TESTING OF STONE 197 his zeal for distinction, devises tests which may be of interest in themselves but which throw no light on the questions of real importance. Classes of Tests Applied. As a matter of convenience, it seems advisable to group the various possible laboratory tests according to the kind of information which they will give re- garding the specimen under test. This has accordingly been done in the following scheme. I. Tests to determine composition ( Chemical analysis and structure II. Tests to determine density III. Tests to determine durability IV. Tests to determine strength ( Microscopic examination I' Specific gravity ^ Weight ^ Porosity f Absorption I Freezing j Sulphate of soda Resistance to acids [Heat 'Compression Transverse Shear Elasticity Fatigue Hardness Abrasion Impact I. TESTS TO DETERMINE COMPOSITION AND STRUCTURE. Chemical Tests. In regard to uniformity in analytical methods marked progress has been made during the past few years. ' Dr. W. F. Hillebrand has described * in great detail the methods of rock analysis followed in the laboratory of the United States Geological Survey, and it seems probable that future progress in the standardization of such methods will follow closely along the lines of his paper. The analysis of materials for the manufacture of Portland cement, a subject which necessitates discussion of analyses of limestone, has been reported f upon by a committee of the Society of Chemical Industry. If followed * W. F. Hillebrand. Some principles and methods of rock analysis. Bull. 176, U. S. Geol. Sur. t Report of the subcommittee on uniformity in analysis of materials for the Portland cement industry. Jour. Soc. of Chem. Ind., vol. 21, pp. 12-30. 198 BUILDING STONES AND CLAYS A V by che^hists engaged in industrial work, the methods advocated in the two papers* noted will result in greater accuracy in deter- mining the chemical composition of rocks, as well as greater uniformity in the statement of results. The practical value of a chemical analysis depends largely on the type of rock in question. In the case of a granite, trap, or other crystalline igneous rock, an analysis is of itself of little service, though it may do some good if taken in connection with a careful microscopical investigation. With sandstones, analyses are somewhat more useful, in determining the character of the cementing material, though even here a microscopical investi- gation will probably be more serviceable. The value of a chem- ical analysis is greater in the case of limestones and slates, particularly the latter. Microscopic Examination. The examination, under the microscope, of thin sections of a stone serves to determine the characters and condition of the component minerals, the shape and method of aggregation of the individual grains; and, in the case of sedimentary rocks, the character of the cementing material. Microscopic examination, therefore, is perhaps the most valuable single test; but it is the one which can least readily be applied by the quarryman or engineer, as instruments and training are rarely obtainable. II. TESTS TO DETERMINE DENSITY. Of the various properties of stone that may be selected for testing, three are so intimately related that they must be con- sidered together under the head of tests to determine density. The three properties in question are: (1) Specific gravity. (2) Weight per cubic foot. (3) Porosity. Of these, the first and second are readily determinable by direct experiment. The third cannot readily or accurately be determined by experiment, but can be ascertained by calcu- lation when the weight and specific gravity are known. Interrelation of These Properties. The specific gravity of any mass of material is the ratio between its density and that of an equal volume of water. There is, therefore, a very simple relation between the specific gravity of any nonporous body LABORATORY TESTING OF STONE 199 and its weight per cubic foot, and the two are convertible accord- ing to the following formulas, assuming that a cubic foot of water will weigh 62.4 pounds. (1) Specific gravity X 62.4 = weight in pounds per cubic foot. ,- N Weight in pounds per cubic foot . ., (2) ' 624 - = specific gravity. If we were dealing with a thoroughly homogeneous and non- porous material, such as rolled steel or coined gold, the above statements would cover the whole case. But in dealing with stone, which is rarely homogeneous and usually very porous, the matter becomes more difficult, and any apparently simple, direct statement regarding it is apt to be misleading. The difficulty arises from the fact that a stone is made up of a number of solid nonabsorbent mineral particles, separated by pore spaces of greater or lesser size and amount. We might attempt to determine the specific gravity of the stone by simply weighing a fragment in air and then in water, using the familiar formula : Weight in air Specific gravity = Loss of weight in water But the value thus obtained would not be the true specific gravity of the stone. It would always be lower than the true specific gravity, because of the pore spaces in the rock. This fact is often stated in discussions of testing methods, and various devices have been employed to overcome the difficulty. In the opinion- of the writer these attempts have been wrongly directed, and have tended to lessen the accuracy of the results rather than increase it. The true specific gravity of any stone is equal to the specific gravity of its solid particles. It can only be determined, there- fore, by grinding the stone to powder, and finding the specific gravity of this powder. Any other method of ascertaining it will give erroneous results, the amount of the error being pro- portional to the porosity of the original rock. The weight per cubic foot of the stone can best be obtained by direct weighing of a carefully measured cube or slab. The accuracy of this direct method depends on the precision of the measurements and weighing, and on the smoothness of the faces 200 BUILDING STONES AND CLAYS of the cube. A polished specimen, for example, should give very accurate results. The porosity of the stone can be deduced if the true specific gravity and weight per cubic foot are known. The formulas for converting these three factors are as follows: g = true specific gravity of powder. w = apparent weight per cubic foot by direct weighing. p = percentage of pore space. -j> = 6240 g - 62.4 gp 100 ( 2 >* = io -SS- 100 w (3) g = 6240 - 62.4 p These formulas are of use, of course, only when the true specific gravity and the weight per cubic foot of the stone have been cor- rectly determined. When the so-called " specific gravity " and " weight per cubic foot " have been determined by the inaccurate methods in common use the formulas cannot be applied. Methods of Determining Weight per Cubic Foot. The weight per cubic foot of a stone, as that term is here used, is the actual weight of a cubic foot of the dry stone, without allowance for pore spaces. Two methods may be employed in making this determination. The first of these, though apparently the cruder, is in reality subject to less error. (1) Direct Weighing. A cube or slab of the stone is carefully measured, and its volume calculated. It is then weighed with equal care. The weight per cubic foot is then, simply, weight in pounds per cubic foot = weight of specimen in pounds X : : r^ : r The specimen, before volume of specimen in cubic inches weighing, should have been dried for several hours at a tem- perature of about 110 C. in order to remove water. As errors in either measuring or weighing decrease as the size of the speci- men increases, it should be as large as possible. With polished, well-squared specimens the results obtained by this method are very accurate. Their accuracy decreases, of course, as the faces LABORATORY TESTING OF STONE 201 of the cube or slab are rougher or more irregular; but the cubes employed for compression tests will give very satisfactory re- sults. (2) Weighing in Water. A method which some testing labor- atories use to determine what they erroneously call the " specific gravity " of stone, is in reality a very fair method for obtaining its weight per cubic foot. The specimen is dried and weighed in air. It is then suspended in water and weighed as quickly as possible, so as to avoid much absorption. If w equals weight in air, and w 1 , weight in water, then: w Weight in pounds per cubic foot = - - X 62.4. w w 1 Porosity. The percentage of porosity of a stone is the ratio between the volume of pore spaces in any specimen and the total apparent volume of the specimen. There is no simple method of determining this by direct experiment, but on a preceding page it has been pointed out that the porosity can be calculated readily if the true specific gravity and the apparent weight per cubic foot have been determined. The formula to be used for this purpose is 100 w in which p = percentage of pore space. w = apparent weight in pounds per cubic foot. g = true specific gravity. The value thus obtained is of interest simply as fixing a maxi- mum for the amount of water that can be absorbed by the stone under the most favorable circumstances possible. Actually, as below noted, the absorption rarely approaches this theoretical maximum. Value of Density Tests. (1) When stone is to be used for certain purposes, a high weight per cubic foot is per se an ad- vantage. This is particularly the case with regard to stone to be used under water, as in dams, breakwaters, and shore pro- tection works. For such purposes a trap, weighing perhaps 180 pounds per cubic foot, is a far more satisfactory material than a sandstone weighing only 140 pounds. The real ratio 202 BUILDING STONES AND CLAYS between the value of these two stones would not be simply that of their weights, as 180 : 140, but a much higher ratio. As Johnson has pointed out, the effective weight of a stone in under- water construction is its weight minus that of an equal quantity of water. In the example just cited, therefore, the real ratio of effectiveness between the two rocks would not be simply 180-62.4 117.6 140-62.4' -7 or almost 11: 7. Obviously there is a distinct advantage to be gained by using stone of high specific gravity for such purposes. (2) Aside from the case above mentioned, where high specific gravity is of itself desirable, it is always desirable because of the other physical properties which it indicates. It may be accepted as axiomatic that in any particular group of stones, the one show- ing the highest weight per cubic foot is almost certainly the strongest and least absorbent. A limestone weighing 160 pounds per cubic foot is, therefore, other things being equal, to be preferred to one weighing only 140 pounds. The same is true with regard to sandstones. Granites and traps, however, show such a small percentage of absorption that the relation between weight and absorption becomes of little practical importance. m. TESTS TO DETERMINE DURABILITY. Expansion. It has long been recognized that much of the lack of durability of building stone is due to the effects of changes of temperature. These operate to disintegrate the stone be- cause, except in the case of an entirely homogeneous material, the various component minerals will have different ratios of expansion on heating, as in a granite, while in sandstones the cementing material and the enclosed grains or fragments may expand unequally. The tendency of a stone to exfoliate or disintegrate under changes of temperature can obviously be tested directly, and uniformity in the method of applying the test may be obtained without difficulty. LABORATORY TESTING OF STONE 203 Absorption. The mineral particles of which a stone is com- posed are themselves practically nonabsorbent, but a certain amount of space always exists between these particles. This percentage of pore space can be determined from formula 2 on page 200. Its principal interest lies in the fact that it fixes a maximum limit for the amount of water that the stone can absorb. A stone containing 5 per cent of pore spaces can ob- viously never absorb more water than would fill this 5 per cent of unoccupied space. In reality, under ordinary conditions, it would never absorb nearly as much as this theoretical maximum. Direct absorption tests can of course be readily carried out; and would be of value if different experimenters would accept some definite standards of practice in the matter. Frost Tests. Changes of temperature, as indicated above, may of themselves cause serious injury to a stone; but when taken in connection with the action of water contained in the pores of the stone, the effect is greatly augmented. The tests applied for expansion are mainly to determine the effect of alter- nate heating and cooling, and particularly of high heating and rapid cooling. The tests for porosity or absorption, on the other hand, are carried out with a view to determining the probable resistance of the stone to the action of frost. Other things being equal, it is obvious that the stone which absorbs the greatest quantity of water per cubic inch in a given time will be the stone that is subject to the greatest injury at low temperature, owing to the freezing of the water contained in it. It is of course de- sirable to check up this mode of reasoning by carrying out actual freezing tests; and several valuable series of such tests are on record. The action of frost is frequently simulated by using in the absorption test, instead of pure water, a saturated solution of some salt, of which expansion, on solidifying, would tend to crack or disintegrate the stone. Tests of this type have, how- ever, fallen largely into disuse. They will be discussed briefly after actual freezing tests have been considered. In 1890 Gerber * tested a small series of western building stones, the specimens being subjected to alternate thawing and freezing by immersing them in water during the day, and at night placing them in cold storage rooms kept at an average temperature of * Trans. Am. Soc., Vol. 33, p. 253. 204 BUILDING STONES AND CLAYS to 4 F. This was done for about twelve days, and resulted in the following losses of weight: TABLE 98. EFFECT OF FREEZING TESTS. (GERBER.) Kind of stone. Location. Loss of weight in per cent. Limestone Bedford, Ind 097 Bedford Ind 103 Stone City, Iowa 134 Stone City, Iowa 053 Mankato, Minn 113 Mankato, Minn 106 Winona Minn 049 Winona Minn. 043 Hannibal Mo. 154 Sandstone Ashland, Wis. 068 it Ashland, Wis 088 Beare * subjected a small series of British building stones to actual freezing tests. The cubes were soaked in water all day, and then at night placed outside, being thus subjected to tem- peratures of from 20 to 32 F. In the morning the specimens were brought inside and thawed by gentle warming. This process was repeated ten or twelve times, and then the cubes were exposed to the atmosphere and rains for two or three weeks in thawing weather. On weighing and testing it was found that (1) granite cubes showed no perceptible loss of weight; (2) some limestone and sandstone cubes showed losses, never exceeding one-fifth of 1 per cent; (3) none of the cubes showed any loss of strength as compared with unfrozen cubes. Taking into con- sideration the fact that most of the limestones tested were porous, loose-grained volites, and that the group of sandstones also included some very porous specimens, the small loss of weight would seem to prove that this method of testing could hardly be regarded as satisfactory. Buckley's tests on Wisconsin stones gave the following results : Proc. Institute Civil Engineers, vol. 107, pp. 350, 351 (1892). LABORATORY TESTING OF STONE 205 TABLE 99. EFFECT OF FREEZING TESTS. (BUCKLEY.) Kind of stone. Quarry. Location. 1 *1 P *o Compressive strength, pounds per square inch. i 5 Granite Limestone Sandstone Amberg Granite Co. . Berlin Granite Co Nelson Granite Co. . . French Granite Co. . . Granite Heights Co. . Jenks' quarry Leuthold quarry Milwaukee Mon. Co. . Montello Granite Co.. New Hill o' Fair Pike River Granite Co. Athelstane Berlin .025 .000 .03 .006 .025 .035 .02 .015 .01 .05 .015 .16 .00 .14 .013 .00 .00 .00 .035 .012 .045 .08 .435 .175 .140 .115 .200 .195 .026 .13 .133 .00 19,988 24,800 45,841 24,229 22,507 18,023 25,000 34,640 38,244 27,262 23,062 30,680 8,098 24,522 35,970 32,992 41,620 32,710 8,799 18,477 12,827 30,745 4,173 5,495 5,421 4,718 5,991 2,722 12,405 4,040 5,329 4,319 10,619 36,009 32,766 16,019 20,306 15,764 14,886 31,844 35,045 19,368 20,442 17,005 7,527 28,392 20,777 28,133 27,366 13,986 9,462 25,779 7,554 14,943 2,220 5,930 3,714 4,808 6,903 3,464 6,141 2,958 4,399 3,993 Berlin High Bridge. . . . Granite Heights Irma Granite City Berlin Montello Granite Heights Amberg Knowles Bauer's quarry Bridgeport Stone Co. Gillen Stone Co Laurie Stone Co Lee Bros, quarry Marblehead Stone Co. Menominee Falls Co. Giesen quarry Story quarry Bridgeport Duck Creek. . . . Sturgeon Bay Genesee Marblehead .... Lannon Fountain City. . Wauwatosa . . Voree quarry Burlington Sturgeon Bay . . . Argyle Washington Stone Co. Argyle Brownstone Co. Ashland Brownstone Co Babcock & Smith. . . . Bass Island B. Co Duluth Brownstone.. . Co Dunnville quarry Grover quarry Presque Isle .... Houghton Bass Island Fond du Lac .... Dunnville LaValle Bayfield Pike quarry Port Wing quarry Prentice Brownstone Co. Port Wing Houghton The Brard Test with Sodium Sulphate. In order to obtain any very striking results, actual freezing tests have to be ex- tended over a long period of time. To avoid this inconven- 206 BUILDING STONES AND CLAYS ience, it was early suggested that the effect of frost might be simulated by immersing the specimen in a saturated solution of certain salts, and then allowing the absorbed salts to crystallize out of the stone. The salt most commonly used for this purpose is sulphate of soda, suggested first by Brard, whose name is therefore often attached to the test. The test as carried out by Luquer was as follows: A saturated cold solution of sulphate of soda was prepared. " The specimens, which had been carefully prepared, brushed, dried, and weighed, were boiled in the sulphate of soda for half an hour, in order to get complete saturation. At the end of the half hour it was noticed in every case that the solution was slightly alkaline, though at the start it had been neutral. In order to prevent any continued chemical action the beakers were emptied, the specimens rapidly washed with water, and the beakers immediately refilled with the neutral sulphate solution. After soaking for several hours, the specimens were hung up by threads, and left for twelve hours (during the night) in a dark room. In the morning all the specimens were covered with an efflorescence of the white sulphate of soda crystals; they were then allowed to soak in the solution during the day, and again hung up at night. Efflorescing for about twelve hours and soak- ing for about the same time constituted a period. The experi- ments lasted for eight periods. . . . During the tests the solution was renewed from time to time, and appeared to remain neutral. The temperature of the room varied from 60 to 70 F. (18 to 21 C.). Those specimens most affected began to show the disintegrating action of the solution very early in the course of the experiments. At the end of the ten (8 ?) days the specimens were sprayed with the stream from a wash bottle to remove any adhering particles, washed in water to remove the sulphate of soda, carefully dried in an air bath at about 120 C. and weighed again." These tests were carried out in order to determine whether or not the sulphate of soda test gave results directly comparable with those obtained by actual freezing, a duplicate series of specimens being tested at the same time in the latter manner. The results of the two series of tests are presented in the follow- ing table, and it will be seen that the correspondence is far from satisfactory. LABORATORY TESTING OF STONE 207 It may also be noted here that Gerber* carried out similar comparative tests, and that his results were equally unsatisfactory . TABLE 100. RELATION OF FREEZING AND SODIUM SUL- PHATE TESTS. (LUQUER.) Kind of rock. From Loss of weight. Per cent. Ratio of re- sults. Soda Sul- phate of soda. Freez- ing. freezing Granite : Coarse-grained Gallager's, Me. 0.1551 0.0655 0.0516 0.0633 0.0384 0.0138 0.0176 * * t 0.0310 0.0230 0.0207 0.1063 0.1421 0.6874 0.0686 Medium-grained Fine-grained Fine-grained gneiss Jonesborough, Me. . . Hallowell, Me Bedford, N. Y Keeseville, N. Y Marble: Coarsely-crystalline; magnesian Medium-grained; magnesian. . . Fine-grained; nonmagnesian. . . . Sandstone : Fine-grained Pleasantville, N. Y. . Tuckahoe, N. Y ? Belleville, N. Y. . (t ? 0.1078 0.1701 0.2599 0.4765 1.4518 4.8212 0.2486 Coarser-grained Badly-decomposed Pressed brick * About same as Jonesborough stone . t Less than Jonesborough stone. The defect of the Brard test becomes apparent when the above tests, or any other long comparative series, are examined care- fully. The sulphate of soda method does give measurable results in short time. But its results are different from those of actual freezing tests not only in intensity but in kind. Chemical action is introduced which attacks the specimen in a way very different from that of frost, and the result is that the two tests are in no way comparable. Inasmuch as the only excuse for making the Brard test is the idea that its effects closely simulated those produced by frost, it is evident that it has failed in its mission, and that it requires no further consideration. It may be added that in these days of cold-storage warehouses it is not such a difficult matter to carry out actual freezing tests at any time of the year. Resistance to Acids. Structural stone, particularly when employed in manufacturing cities, may be subjected to attack by various acids present in the atmosphere. Carbonic acid is * Trans. Amer. Soc. C. E., vol. 33, p. 253. 208 BUILDING STONES AND CLAYS always present in air, though normally only in small percentages, while nitric, hydrochloric, sulphuric, and sulphurous acids occur in certain regions. Though these acids are present in very small amounts, their effect on stone, when exerted through a long series of years, may be noticeably injurious, and accordingly various tests have been suggested to determine the amount of this effect on various kinds of stone. In testing the influence of carbon dioxide, Wilber * used samples weighing about 50 grams. These were dried at 212 F. and weighed; then placed on a perforated shelf under a large bell jar. " The bell jar was placed in a shallow pan, and enough water poured into the pan to make a water seal for the bell jar. Inlet and exit pipes were introduced into it and a stream of washed carbonic acid passed into the jar until all air was expelled. The openings were then closed and the contents allowed to stand three days at a temperature of about 70 F. Carbonic acid gas was again passed in, and this operation was repeated, at intervals during the fifty-two days of the continuance of the test. The samples were then removed and soaked for four days in distilled water, and were afterwards dried in an air bath, at a temperature of 212 F., to constant weight." The percentage of weight lost during the operation was then calculated, with the results shown in Table 101. In the course of the New York series of tests already noted, Wilber also experimented f on the effects of dilute sulphuric acid. " Small cubes, three-fourths of an inch on a side, were used for this test. The samples were dried in a water bath at 212 F. to a constant weight. They were then placed upon a perforated support and immersed in dilute sulphuric acid. The acid solu- tion contained one per cent of sulphuric acid, H 2 SO 4 , and the volume used at once was two gallons. After an immersion of forty hours the acid was drawn off and replaced by a fresh supply. This remained upon the samples for twenty-four hours, when it was run off and a third fresh portion added, which was allowed to remain eight hours. It was then drawn off and a gentle stream of clear water passed through the vessel for some time, until the samples were entirely cleansed from the effects of the * Bulletin 10, N. Y. State Museum, p. 357 (1890). t Ibid, p. 358 (1890). LABORATORY TESTING OF STONE 209 solvent action of the acid. They were then carefully removed to the water bath and dried at 212 F. to constant weight." Wilber also experimented* on the effect of sulphurous acid gas. These experiments were carried out exactly like those in which carbon dioxide was used (see page 208), except that the tests lasted only thirty-one days. TABLE 101. TESTS WITH ACIDS. (WILBER.) Stone. Locality. C0 2 . HS 2 . H 2 SO 4 . Granite Grindstone Is., St. Lawrence Co., N. Y. . Keeseville Essex Co N Y 0.006 0.002 0.007 0.017 0.13 06 Hallowell IMaine 0.029 0.024 0.08 Marble Tuckahoe, Westchester Co., N. Y Pleasantville, Westchester Co., N. Y Glens Falls Warren Co., N. Y 0.021 0.004 0.005 0.007 0.250 0.150 0.120 5.25 6.63 2.56 Limestone Gouverneur, St. Lawrence Co., N. Y Sandy Hill, Washington Co., N. Y Plattsburg, Clinton Co., N. Y 0.017 0.012 0.023 0.150 0.150 0.190 2.63 2.51 2.20 Tribes Hill, Montgomery Co., N. Y Canajoharie, Montgomery Co., N. Y Prospect Oneida Co N Y 0.028 0.012 017 0.160 0.160 150 3.03 2.62 2 97 Chaumont, Jefferson Co., N. Y Cobleskill, Schoharie Co., N. Y Onondaga Reservation, Onondaga Co., NY. 0.008 0.010 0.021 0.091 0.130 0.201 2.95 2.58 2 84 Union Springs, Cayuga Co., N. Y Auburn, Cayuga Co., N. Y Williamsville, Erie Co., N. Y 0.011 0.010 0.060 0.082 0.140 0.250 3.77 2.79 2.97 Bowling Green, Ky 0.062 +0.160 5.66 Bedford Ind. 087 +0 019 5 83 C0 2 S 2 H 2 SO 4 Sandstone Potsdam St Lawrence Co N Y 030 004 02 Maiden Ulster Co N Y 032 003 20 Oxford Chenango Co NY. 021 080 20 Duanesburgh, Schenectady Co., N. Y.. . . Oswego Falls, Oswego Co., N. Y. 0.011 Oil 0.065 290 0.63 74 Albion, Orleans Co., N. Y Hulberton, Orleans Co., N. Y (I 11 U 0.092 0.046 037 0.012 0.061 078 0.08 0.08 Portage, Wyoming Co., N. Y Warsaw, Wyoming Co., N. Y Olean, Cattaraugus Co., N. Y. 0.008 0.015 060 0.089 0.250 040 0.42 0.49 44 * Bulletin 10, N. Y. State Museum, p. 358 (1890). 210 BUILDING STONES AND CLAYS TABLE 101. TESTS WITH ACIDS. (WILDER.) (Continued.) Stone. Locality. C0 2 . S 2 . H 2 S0 4 . Sandstone East Longnieadow IVIass 046 055 12 0.040 0.081 0.086 0.051 0.17 076 0.060 Portland Conn 0.074 0.053 0.068 074 0.146 0.161 6 059 0.11 55 n ( ti i U (( Belleville N J 0.080 0.078 0.090 031 0.086 0.003 6 040 0^22 i 6i Berea, Ohio 0.066 0.170 0.45 Lake Superior Mich. 005 100 36 Nova Scotia 025 020 20 Bristow, Va. 079 180 11 Slate Middle Granville, Washington Co., N. Y. 0.104 0.004 0.100 0.070 0.07 Resistance to Fire. The most complete series of tests of the fire resistance of building stones are those by McCourt, from whose report the following extracts are quoted: The samples from each locality were cut into three-inch cubes. Most investigators, who have studied the refractoriness of build- ing stones, have selected one or two-inch cubes; but these sizes do not give as accurate results as the larger ones, for the reason that a small piece becomes easily heated throughout the mass and consequently upon neither heating nor cooling are differen- tial stresses between the interior or exterior likely to be set up, as would be the case if larger cubes are selected. In actual fact in the burning of a building the stone does not become thoroughly heated; the heat penetrates probably but a slight distance into the mass, while the interior may remain compara- tively cold. The heating and cooling of this outer shell causes strains which do not obtain in a stone which has been heated throughout its entire body. One, two and three-inch cubes of the same kind of stone have been tested in the laboratory, and while the smaller cubes stood fire very well, the larger ones were more affected and in some cases went to pieces. It was to avoid this error and to approach more closely the existing conditions in a conflagration that the three-inch samples have been em- ployed in the present series of tests. LABORATORY TESTING OF STONE 211 As far as the number of cubes would admit six tests were made on the stone from each locality, four furnace and two flame tests. For the first set of experiments a Seger gas furnace was used, thus allowing the cube to be gradually and evenly heated. An opening was cut in the cover of the furnace large enough to admit the three-inch cube of stone, to which a wire had been attached to facilitate its handling. One sample was heated at a time. The heat was applied gradually for half an hour until a temperature of 550 C. was reached, which was maintained for half an hour. The tem- perature was measured with a thermoelectric pyrometer. The cube was then taken out and allowed to cool in the air. A second sample was heated, as before, to 550 C., and this was suddenly cooled by a strong stream of water. The third and fourth cubes were heated to 850 C. kept at that temperature for half an hour and cooled slowly and suddenly as in the 550 C. tests. In order to approach more nearly the conflagration condi- tions samples were subjected to two flame tests. In the first case the cube was so placed as to be enveloped on three sides by a steady but not strong gas blast. The flame was allowed to play on the cube for 10 minutes, then the samples were allowed to cool for five minutes after which time the flame was again applied for 10 minutes and the cube was again allowed to cool. To determine the combined action of heat and water a second cube was subjected, as before, to the flame for 10 minutes, then a strong stream of water was turned on to the sample, along with the flame, for five minutes. Then the water was turned off and the flame continued for another five minutes, after which, for five minutes more the flame and water together were allowed to act on the sample. From the details of the tests above given some generaliza- tions can be drawn which are of interest and of value. It is difficult, however, to group the different kinds of stone in any order, for they vary among themselves and also act differently under different conditions. A stone which under some condi- tions stands up very well, will disintegrate under other condi- tions. Thus, for example, the granite from Northville acted very badly on fast cooling after having been heated to 850 C., yet, under the combined action of the flame and water, it was little damaged. Additional variations of this character are brought out by a close study of the tables of fire tests, all of which goes to show that, for one temperature, the order of resistance will differ from the order given for another temperature. At 550 C. (1022 F.) most of the stones stood up very well. The temperature does not seem to have been high enough to cause much rupturing of the samples, either upon slow or fast cooling. The sandstones, limestones, marble, and gneiss were 212 BUILDING STONES AND CLAYS slightly injured, while the granites seem to have suffered the least. The temperature of a severe conflagration would probably be higher than 550 C., but there would be buildings outside of the direct action of the fire which might not be subjected to this degree of heat and in this zone the stones would suffer little injury. The sandstones might crack somewhat, but, as the cracking seems to be almost entirely along the bed, the stability of the structure would not be endangered, provided the stone had been properly set. The gneiss would fail badly, especially if it were coarse- grained and much banded. The coarse-grained granites might suffer to some extent. These, though cracked to a less extent than the sandstones, would suffer more damage and possibly disintegrate if the heat were long continued because the irreg- ular cracks, intensified by the crushing and shearing forces on the stone incident to its position in the structure, would tend to break it down. The limestones and marble would be little injured. The temperature of 850 C. (1562 F.) represents fairly the probable degree of heat reached in a conflagration, though un- doubtedly it exceeds that in some cases. At this temperature we find that the stones behave somewhat differently than at the lower temperature. All the cubes tested were injured to some degree, but among themselves they vary widely in the extent of the damage. All the igneous stones and the gneiss at 850 C. suffered injury in varying degrees and in various ways. The coarse-grained gran- ites were damaged the most by cracking very irregularly around the individual mineral constituents. Naturally, such cracking of the stone in a building might cause the walls to crumble. The cracking is due, possibly, to the coarseness of texture, and the differences in coefficiency of expansion of the various mineral constituents. Some minerals expand more than others and the strains occasioned thereby will tend to rupture the stone more than if the mineral composition is simpler. This rupturing will be greater, too, if the rock be coarser in texture. For example, a granite containing much plagioclase would be more apt to break into pieces than one with little plagioclase for the reason that this mineral expands in one direction and contracts in another, and this would set up stresses of greater proportion than would be occasioned in a stone containing little of this mineral. The fine-grained samples showed a tendency to spall off at the corners. The gneiss was badly injured. In the gneisses the injury seems to be controlled by the same factors as in the granites, but there comes in here the added factor of banding. Those which are made up of many bands would be damaged more severely than those in which the banding is slight. LABORATORY TESTING OF STONE 213 All the sandstones which were tested are fine grained and rather compact. All suffered some injury, though, in most cases, the cracking was along the lamination planes. In some cubes, however, transverse cracks were also developed. The variety of samples was not great enough to warrant any conclusive evidence toward a determination of the control- ling factors. It would seem, however, that the more compact and hard the stone is the better will it resist extreme heat. In a general way the greater the absorption, the greater the effect of the heat. A very porous sandstone will be reduced to sand and a stone in which the cement is largely limonite or clay will suffer more than one held together by silica or lime carbonate. The limestones, up to the point where calcination begins (600-800 C.), were little injured, but above that point they failed badly, owing to the crumbling caused by the flaking of the quicklime. The purer the stone, the more will it crumble. The marble behaves similarly to the limestone, but, because of the coarseness of the texture, also cracks considerably. As has been mentioned before, both the limestones and marble on sudden cooling seem to flake off less than on slow cooling. The flame tests cannot be considered as indicative of the probable effect of a conflagration upon the general body of the stone in a building, but rather as an indication of the effect upon projecting cornices, lintels, pillars, carving, and all thin edges of stonework. All the stones were damaged to some extent. The granites from Keeseville and Northville stood up very well; the limestones were, as a whole, comparatively little injured, while the marble was badly damaged. The tendency seems to be for the stone to split off in shells around the point where the greatest heat strikes the stone. The temperature of the flame probably did not exceed 700 C., so it is safe to say that in a conflagration all carved stone and thin edges would suffer. However, outside of the intense heat, the limestones would act best, while the other stones would be affected in the order: sandstone, granite, gneiss, and marble. After having been heated to 850 C. most of the stones, as observed by Buckley,* emit a characteristic ring when struck with metal and when scratched emit a sound similar to that of a soft burned brick. It will be noted that in those stones in which iron is present in a ferrous condition the color was changed to a brownish tinge owing to the change of the iron to a ferric state. If the temperature does not exceed 550 C., all the stones will stand up very well, but at the temperature which is probable in a conflagration, in a general way, the finer-grained and more compact the stone and the simpler in mineralogic composition the better will it resist the effect of the extreme heat. The order, * Mo. Bureau Geol. and Mines, Ser. 2 (1904), 2:50. 214 BUILDING STONES AND CLAYS then, of the refractoriness of the New York stones which were tested might be placed as sandstone, fine-grained granite, lime- stone, coarse-grained granite, gneiss, and marble. IV. TESTS TO DETERMINE STRENGTH. Crushing Strength. It has often been pointed out that no stone which an engineer is likely to use will ever fail by crushing, for even in such massive masonry structures as the Washington Monument and the Brooklyn Bridge piers the compression per square inch at the base is much below that which even a rela- tively weak building stone will bear. It is pointed out, more- over, that though a small test piece of a given limestone may fail by crushing at, say, 12,000 pounds per square inch, every natural exposure of the rock proves to us that in larger masses it is practically uncrushable. In spite of these facts, the test most commonly carried out, when quality of a stone is in question, is that for crushing strength. Even though this test be unnecessary, it could, if carried out uniformly, give us certain information of value, and be a means of comparing the strength of different stones. Unfortunately, however, there is at present little uniformity in the matter. The apparent " compressive strength per square inch," as shown by any given stone in the testing machine, is known to vary with the shape of the test piece, its size, and the character of the bearing surfaces; but sufficient experiments have not been car- ried out to determine the laws of these variations. In the matter of size of test piece, Gillmore's earlier experi- ments seemed to prove that a large cube gave higher compressive resistance per square inch than a small cube, and he constructed a formula showing the variation in compressive strength in relation to size of cube. This formula will frequently be found quoted in engineering and geological treatises, though within a year of its announcement Gillmore had determined, from the results of a longer series of experiments, that the so-called law did not hold true. Regarding the shape of test piece, it has been determined that a prism whose height is one and one-half times the width of its base will give far more accurate results than the cube. This determination has had little effect on testing practice, however, the cube being employed as heretofore. LABORATORY TESTING OF STONE 215 TABLE 102.* EFFECT OF BEARING MATERIALS ON STRENGTH OF SANDSTONE. (BEARE.) Name of stone. Average compressive strength. Loss of strength due to lead, per cent. Plaster of Paris, pounds per square inch. Lead sheet, pounds per square inch. Binnie 6,339 6,115 10,382 8,682 13,408 3,942 3,942 4,637 4,995 6,361 37.8 35.5 55.3 42.5 52.6 Hermand White Hailes Arbroath , Craigleith * Proc. Institution Civil Engineers, vol. 107, p. 344. TABLE 103. EFFECT OF POSITION ON CRUSHING STRENGTH OF STONE. Ult. compr. Kind of rock. Locality. Tested by Size of cube. strength, Ibs. per sq. in. Ratio, bed -5- edge. Bed. Edge. Syenite French Creek, Pa R. L. Humphrey... In. 8 17,274 7,910 2.18 2 19,997 14,348 1.38 Gneiss, light color Chester, Pa 8 9,505 6,426 1.48 li ** 2 6,097 5,446 1.12 Gneiss, dark color Germantown, Pa 8 11,636 13,984 0.83 " * 2 19,891 15,555 1.28 Holmesburg, Pa Lathbury & Spack- man 5* 21,684 19,527 1.11 Mica schist Conshohocken, Pa. ... R. L. Humphrey . . . 8 2 10,417 20,038 7,532 15,680 1.38 1.28 Roofing slate Brownville, Me Mass. Inst. Tech 1 29,270 16,750 1.75 Sandstone Curwensville, Pa R.. L. Humphrey 8 7,513 4,463 1.68 " " " ** 2 10,218 8,013 .27 Irumberville, Pa it 8 14,841 8,637 .72 1/angford, Ky. Vatertown Arsenal . . 2 2 15,135 27,703 12,341 22,923 .23 .29 Albion, N. Y Berlin Hts., Ohio Gillmore 3 14,250 12,000 .19 Limestone Bowling Green, Ky. . . Vatertown 5 6,998 6,387 1.10 TABLE 104. EFFECT OF METHOD OF DRESSING CUBES.* Modulus c 1 Rupture. Compres- sion. Elasticity. Sawed specimens, average Tool-dressed specimens, average 2,338 1,477 12,675 7 857 4,889,480 2 679 475 Ratio of strength, tool-dressed -5- sawed.. . 63% 62% 55% * llth Ann. Rep. Indiana Dept. Geology, p. 39 (1881). 216 BUILDING STONES AND CLAYS Transverse Strength. Little attention is usually paid to testing the transverse strength of building stones, except in the case of stones intended for use as flagging, lintels, etc. This neglect is the more curious because building stone, in actual con- struction, often fails under transverse strain, as may be seen in the walls of many buildings. In theory, of course, a building should be so constructed as never to subject its wall material to anything but a direct compressive strain. In practice, however, the case is very different. Owing to bad masonry work, or more generally to the unequal settlement of foundations, ' transverse strains do frequently occur, and their effect is shown by vertical cracks in the poorer or weaker stones of the walls. In determining transverse strength the formula used is: in which formula R = modulus of rupture in pounds per square inch. W = concentrated load at center in pounds. L = length between supports, in inches. B = breadth in inches. D = depth in inches. Hardness. The resistance of stone to mechanical wear is rarely of sufficient importance to justify testing, when the stone is used strictly as a building material. Flagging, steps, and sills are, however, subjected to considerable wear, and it is possible that some simple abrasion test might be of service. The only structural stone, however, that really fails, owing to ordinary mechanical wear, is serpentine, which is entirely too soft to be used in any unprotected situation. LIST OF REFERENCES ON TESTS OF BUILDING STONE. In addition to such general works as those of Gillmore, Merrill, Johnson and the Watertown Arsenal reports, the references in the following list may be found serviceable. Bach, C. Experimental investigations upon granite. Zeits. der Verein Deutscher Ingen., Feb. 27, 1897. Bach, C. The relation between extension and strength in sandstone. Zeits. der Ver. Deutsch. Ingen., Sept. 1, 1900. Buckley, E. R. Building and ornamental stones of Wisconsin. Bull. 4, Wisconsin Geol. Sur. 1898. LABORATORY TESTING OF STONE 217 Garrison, E. L. Notes upon testing building stone. Trans. Am. Soc. C. E., vol. 32, pp. 87-98. 1894. Gary, M. The testing of natural stone in the years 1895-1898. Mitt- heilung aus der Konig. Tech. Versuchsanhalten, No. 5. 1898. Greenleaf, J. L. Building stones. School of Mines Quarterly, vol. 1, pp. 27-39, 52-63. 1880. Griibler, M. The strains in grindstones and emery wheels. Zeits. der Verein Deutscher Ingen., July 24, 1897. , . Experiments upon the strength of grindstones. Zeits. der Verein Deutscher Ingen., Oct. 21, 1899. Hall, J. Report on building stones. 39th Ann. Rep. New York State Museum, pp. 186-225. 1886. Howe, M. A. Experiments to determine the effect of the bedding material on the strength of marble. Engineering News, Feb. 15, 1894. , Johnson, T. H. Experiments upon the transverse strength and elasticity of building stone, llth Ann. Rep. Indiana Dept. Geol., pp. 34-42. 1882. Julien, A. A. Building stones elements of strength in their constitu- tion and structure. Jour. Franklin Institute, vol. 147, pp. 257-286, 378-397, 430-442. 1899. Luquer; L. M. The relative effects of frost and the sulphate of soda tests on building stones. Trans. Am. Soc. C. E., vol. 33, pp. 235-256. 1895. Merrill, G. P. The physical, chemical, and economic properties of building stones. Reports Maryland Geol. Sur., Vol. 2, pp. 47-123. 1898. Perry, G. W. The relation of the strength of marble to its structure. Engineering News, vol. 52, p. 45. 1891. Raymond, C. A., and Cunningham, E. W. Building stone. Engineer- ing News, March 28, 1895. Smock, J. C. Building stone in New York. Bull. 10, N. Y. State Museum, 396 pp. 1890. PART II. CLAYS. CHAPTER XIII. CLAYS: GENERAL CLASSIFICATION. Definitions of Clay, Shale, and Slate. The term clay is applied to fine-grained unconsolidated natural materials which possess the property of plasticity when wet, while they lose this property and harden on being strongly heated. Clays are readily molded in all desirable shapes when wet; and this property is one factor in the usual commercial definition of a clay: though the typical kaolins are not plastic. Since the clays are, as described below, the finer debris resulting from the decay of many different kinds of rocks, they will naturally differ greatly among themselves as regards composition, properties, etc., and these differences prevent the formulation of a more precise definition. Clays are rock material in an exceedingly fine state of subdi- vision, ultimately derived from the decay of older rocks, the finer particles resulting from this decay being carried off and deposited by streams along their channels, in lakes, or along parts of the sea coast or sea bottom as beds of clay. In chemical composition the clays are composed essentially of silica and alumina, though iron oxide is almost invariably present in more or less amount, while lime, magnesia, alkalies, and sulphur are of frequent occurrence, though usually only in small percentages. The materials known respectively as shales and slates are of practically the same composition and ultimate origin, but differ in their degree of consolidation. Shales are clays which have become hardened by pressure. The so-called " fire clays " of the coal measures are shales, as are many of the other " clays " of commerce. The slates include those clayey rocks which through pressure have gained the property of splitting readily into thin parallel leaves. 218 CLAYS: GENERAL CLASSIFICATION 219 Origin of Clays ; General Statement. When rocks of any kind are exposed to atmospheric action, more or less rapid disin- tegration sets in. This is due partly to chemical and partly to physical causes. It is hastened, for example, by the dissolving out of any soluble minerals that may occur in the rock, by the expansion and contraction due to freezing, and by the action of the organic acids set free by decaying vegetable matter. The more soluble ingredients of the rock are usually removed in solution by surface or percolating waters, while the more in- soluble portions are either left behind or are carried off mechani- cally by streams. These relatively insoluble materials, when sufficiently fine-grained, constitute the clays. When they are left as a deposit in the spot where the original rock disintegrated they are called residual clays, while if they have been removed from the site of the present rock they are termed transportation clays. If the materials are carried off mechanically by surface waters and finally deposited along river beds, in lakes, or in the sea they are termed transported or sedimentary clays. In a third class, of limited areal distribution but of considerable importance where they occur, are the glacial clays which owe their position to the great ice sheets which formerly covered most of the north- ern portion of the United States, the clays in question having been deposited under or in front of these glaciers. A class of still more limited extent and importance includes the eolian or wind-borne clays, the example usually quoted being the loess clays, which are supposed by some geologists to have been transported and deposited by the winds. So far as origin is concerned, clay deposits are therefore due to the cooperation of two sets of agencies chemical and me- chanical. With regard to the residual clays, chemical agencies have in some cases been the more important ; but the transported or sedimentary clays are, in their present deposits, due almost entirely to purely mechanical causes. Classification Based on Origin. The facts which have been briefly stated above naturally lead toward a classification of clays based on the methods of origin and of deposition. A satis- factory working classification of this type is presented below in outline form; after which each of the groups named in this outline will be separately discussed in more detail. A. Residual clays, resulting from the decay in place of 220 BUILDING STONES AND CLAYS igneous rocks, of shales, or of clayey limestones. This group may be subdivided into three, according as the clay is derived. 1. From the decay of igneous rocks. 2. From the decay of shales or slates. 3. From the decay of more or less clayey limestone. B. Transported clays, resulting from the transportation by water (or more rarely by ice or wind) of both the residual clays of Class A and of all sorts of finely-ground rock material, and the deposition of this material at favorable points more or less distant from its point of origin. The clays of this class may be subdivided according to their method of transportation, their point of deposition, or their present physical state. A sub- classification recognizing these three factors is as follows: 1. Water-borne clays; transportation effected by water. (a) Marine clays, deposited in salt-water basins. 1. Marine clays proper (i.e., soft clays). 2. Shales. 3. Slates. (6) Stream clays, deposited along the courses of streams or rivers. (c) Lake clays, deposited in lakes or ponds. 2. Ice-borne or glacial clays; transportation effected by glacial ice. 3. Wind-borne or eolian clays; transportation effected by the wind. CHAPTER XIV. RESIDUAL CLAYS. Origin of Residual Clays. The residual clays owe their origin to the decay or disintegration of some rock mass under the action of natural agencies, and to the consequent accumu- lation of the more insoluble or resistant portions as a residual material on the surface of the parent rock. The natural agents which effect this decay and disintegration may be either chemical or mechanical usually both sets of forces are at work. The manner in which the decay and disintegration of the rock are produced will depend on the character of the agent and on the character of the rock. The methods of action and the effects produced are so different, on different types of rock, that it seems advisable to discuss the subject under three special head- ings, each of which will cover the formation of an important class of clay deposits. By far the majority of residual clays are de- rived from the decay of igneous rocks, of shales, or of clayey limestones for the sandstones rarely yield clay deposits of any kind. Residual from Decay of Igneous Rocks. The igneous rocks usually contain a number of minerals, some of which are com- paratively unaffected by weathering, while others yield with considerable rapidity. A granitic rock may be taken for ex- ample, composed of quartz, feldspar, mica, and probably a little hornblende. When a rock of this character is exposed at the surface, its quartz would be practically unaffected by the ordinary weathering agents; its feldspar would decay with comparative rapidity, while its mica and hornblende would also alter, though less strikingly than the feldspar. Extremes of cold and heat would tend to disintegrate the rock physically, and so make its minerals more open to attack from percolating waters carrying dissolved acids. The decay of feldspars undoubtedly gives rise to certain clay deposits of interesting type, and though the importance of this 221 222 BUILDING STONES AND CLAYS fact has been greatly exaggerated in clay literature, the subject is worth some consideration here. The feldspars are essentially silicates of alumina and potash, soda or lime. The composition of the different feldspar species is discussed in some detail on page 25, to which reference should be made for further data on. the subject. In the present case it will be sufficient to take up the most familiar variety of feldspar orthoclase and to trace the changes which it undergoes during chemical decay. Orthoclase has the formula K 2 O, A1 2 O 3 , 6 SiO 2 , corresponding in composition to silica 64.60 per cent, alumina 18.50 per cent, potash 16.90 per cent. When exposed to the action of waters carrying in solution carbonic, sulphuric, and organic acids, a chemical decomposition of the mineral takes place, resulting in the removal of the potash and most of the silica (and of any lime or iron that may be present), the formation of a hydrous aluminum silicate, and the segregation of the residual silica. The aluminum silicate thus formed may be any one of a long series of which kaolinite and pholerite are probably the most prominent. The chemical relationship existing between the original feldspar and these two possible final products is shown in the following comparative table. TABLE 105. COMPOSITION OF ORTHOCLASE, KAOLINITE, AND PHOLERITE. Orthoclase. Kaolinite. Pholerite. Silica (SiO 2 ) Alumina (A1 2 O 3 ) Potash (K 2 O) 64.6 18.5 16 9 46.3 39.8 39.3 45.0 Combined water. . . . Formula Specific gravity k 2 b,'Ai 2 o 3 r6si6 2 2 57 13.9 A1 2 O 3 , 2 SiO 2 , + H 2 2.5 15.7 2Al 2 O 3 ,3SiO 2 , + 4H 2 Pure kaolinite and pholerite are plastic, highly refractory, white-burning materials. As formed by the decay of granitic rocks, however, the products are impure, containing grains or masses of the relatively insoluble constituents of the granite, i.e., quartz, mica, hornblende, etc. These impurities operate to reduce the plasticity and refractoriness of the product, and often to alter its color when burnt to yellow or even red. Of RESIDUAL CLAYS 223 course the less quartz and mica contained in the original rock the purer would be the product, and the ideal kaolinite (or pholerite) would therefore result from the decay of a vein of pure feldspar. All that has been said in the above paragraphs concerning the chemical decay of feldspar must be read with the understanding that this is only one phase of the weathering of an igneous rock,, and that often it is not even an important'phase. To ascribe all clay deposits, ultimately, to such an origin is simply to misunder- stand the very obvious facts of the case.* Purely mechanical disintegration always plays a large part in the weathering of such rocks, and at times it is the only important agent. Many residual materials will be found which show little sign of chemical alterations or changes, and differ from the unweathered rock only in the fact that they are now fine, unconsolidated products instead of the original mass of interlocking crystals. TABLE 106. ANALYSES OF ACID IGNEOUS ROCKS AND RESIDUAL CLAYS. la. 16. 2a. 26. Silica (SiO 2 ) 66 31 56 40 69 88 51 29 Alumina (Al 2 Os) 18 27 25 62 16 42 OQ fiQ Ferrous oxide (FeO) { 2 51 3 45 1 96 6 33 rerric oxide (Fe^Os) i Lime (CaO) 2 91 37 1 78 07 Magnesia (MgO) Potash (K 2 O) . . 1.22 4 09 0.98 2 99 0.36 K AQ 0.14 1 ^0 Soda (Na 2 O) 3 69 1 36 4 4fi 1 19 Combined water. . . . 61 9 18 36 10 3fi 16. Residuary) Camak > Geor gia. Bull. 9, Georgia Geol. Sur., p. 321. 2o, 26. J, AbOBKUUAI \jO,y ) I'. Residuary) Greenville Georgia. Bull. 9, Georgia Geol. Sur., p. 315. The character of the residual clay resulting from the decay of an igneous rock depends partly on the composition of the original rock, and partly on the degree to which decomposition has pro- * Of recent American writers on the origin of clays, only one has treated this subject with thorough knowledge and a due sense of proportion; and the reader, desirous of making a more detailed study of this phase of the subject will, therefore, do well to consult G. P. Merrill's "Rocks Rock Weathering, and Soils." 224 BUILDING STONES AND CLAYS The effect of the second of these factors is of course obvious, but the first requires some further consideration. The acid igneous rocks such as the granites are rela- tively high in silica, and low in iron oxide, lime, magnesia, and alkalies. The clays which result from the decomposition and disintegration of such rocks are apt, therefore, to be low in the last-named constituents. The basic igneous rocks traps, gabbros, etc. being origi- nally low in silica and relatively high in iron, lime, magnesia, and alkalies, give usually much more impure residual clays than do the acid rocks. Even when chemical action (solution) has been most thorough, much or all of the iron oxide is left behind in the clay; though the lime, magnesia, and alkalies of the original rock may appear in greatly lessened percentages in the residual material. Where mechanical disintegration has played much part in the process, however, then fluxing impurities remain in the residual product. Basic rocks do not occur at the earth's surface in such great masses as the more acid types, nor are they so widely distributed. Because of these facts, clays derived from basic rocks are not of very common occurrence or of great importance to the clay industries. TABLE 107. ANALYSES OF BASIC IGNEOUS ROCKS AND RESIDUAL CLAYS. la. 16. 2a. 26. Silica (SiO 2 ) 46 75 42 44 38 85 38 82 Alumina (A1 2 O 3 ) Iron oxide (Fe2Os) 17.61 16.79 25.51 19.20 12.77 12.86 22.61 13 33 Lime (CaO) 9.46 0.37 6.12 6.13 Magnesia (MgO) 5 12 21 22 58 9 52 Potash (K 2 O) 0.55 49 19 18 Soda (Na 2 O) Water 2.56 0.92 0.56 10.92 0.11 6.52 0.20 9 21 la. Fresh diorite ) Albermarle County, Va. G. P. Merrill, " Rocks, Rock 16. Residual clay) Weathering, and Soils," p. 225. 2a. Fresh pyroxenite ) Albermarle County, Va. G. P. Merrill, " Rocks, 26. Residual clay ) Rock Weathering, and Soils/' p. 226. Residual from Decay of Shales or Slates. Since shales and slates are formed simply by the consolidation of clay beds, it is obvious that simple mechanical disintegration of a bed of shale RESIDUAL CLAYS 225 will cause it to again become a bed of clay. So that wherever shale beds are exposed to weathering we find that along the out- crop the shales have broken down and become soft and plastic. Often the change has gone further than simple disintegration, for during the physical decay of the shale percolating waters may have removed some of its more soluble constituents. TABLE 108. ANALYSES OF CLAYS RESIDUAL FROM SHALE. 1. 2. 3. 4. 5. Silica (SiO 2 ) 71 91 73.30 84 05 72 16 47 00 Alumina (Al 2 Os) 16.24 14.49 9 44 21 76 38 75 Iron oxide (Fe 2 Os) ... . 1.79 1.26 0.28 0.99 95 Lime (CaO) Magnesia (MgO) Alkalies (K 2 O, Na 2 O) 0.18 0.88 3.27 0.19 2.14 4.31 0.23 1.35 2.65 0.22 0.70 5.14 0.70 tr. tr. Carbon dioxide (CO 2 ) Combined water . 4 39 3 57 2 18 4 76 12 94 1. Hot Springs, Ark. Average of four analyses by Geo. Steiger. Bull. 285, U. S. Geol. Sur., p. 409. 2. Mountain Valley, Ark. Average of two analyses by Geo. Steiger. Bull. 285, U. S. Geol. Sur., p. 409. 3. Upper Mill, Pa. Hopkins, Clays of Pennsylvania, pt. 3, p. 10. 4. Fogelsville, Pa. Hopkins, Clays of Pennsylvania, pt. 3, p. 10. 5. Valley Head, Ala. Clays formed by the decay of beds of shale or slate are apt to contain little foreign matter except, perhaps, an occasional fragment of unweathered shale. Of course these fragments are rare near the surface but become more common in the deeper parts of the clay deposit, as the unweathered portion of the rock is approached. Even where frequent, however, they do not in- jure the value of the deposit, for the unweathered fragments of shale are of practically the same compo- sition as the bed of residual clay which is derived from the weathering of thr shale. The form taken by such deposits oi clay (i.e. residual from shales or slates), depends largely on the attitude of the original shale bed and on the topography of the district. If the shale bed was highly inclined to the horizon and outcropped along a hillside (as in Fig. 24) , percolating water and atmospheric agencies might 226 BUILDING STONES AND CLAYS Fig. 25. Interbedded shales and limestone. readily disintegrate the shale for some distance down from the outcrop. The resulting clay deposit would still be in the form of a bed, with a dip corresponding to that of the original shale bed. In one particular case, however, a very marked change in atti- tude may be brought about by the weathering of the rocks; and this special case is of much im- portance since it has given rise ^ valuable clay deposits . * J . . . in southeastern Pennsylvania, in Alabama, and elsewhere. The case in question is when the shale was originally inter bedded with limestone, both series of rocks dipping at an angle of 15 degrees to 50 degrees. The effect of weathering on such an outcrop is twofold, for while the shale weathers into clay, most of the limestone is dis- solved, so that the soft clay beds gradually sink down to form a thick and irregularly-shaped deposit. This deposit con- tains not only the softened shale, but also any insoluble material that was contained in the original limestone. When such a clay deposit is examined, therefore, masses of fairly pure shale clay will be found inclosing layers of less pure and limestone residual, often containing fragments or nodules of chert or flint. If the shale bed had been horizontal or nearly so, and were now exposed along a valley bottom, the clay deposit would probably be more irregular in thickness, as indicated in Fig. 27. Fig. 26. Effect of weathering on shale- limestone strata. Fig. 27. Horizontal beds of shale-clay. For in this case the depth of disintegration of the shale would depend more on accidental features, such as the existence of joint planes, thinness of soil cover, etc. RESIDUAL CLAYS 227 An interesting and somewhat exceptional case of the formation of a high-grade residual clay from sandstone has recently been noted by Loughlin.* The occurrence is at West Cornwall, Litchfield County, Connecticut, where a highly feldspathic sand- stone has decayed in place. The resulting product is a mixture of quartz grains and a very pure residual clay or " kaolin." Of course the material requires washing, in order to free the clay from the sand. An analysis of the washed product gave the following results: Silica (SiOa) 47.50 Alumina (A1 2 O 3 ) 37.40 Iron Oxide (Fe 2 O 3 ) 0.80 Lime (CaO) tr. Magnesia (MgO) 0.00 Alkalies (K 2 O, Na 2 O) 1.10 Water 12.48 Residual from Decay of Limestones. The formation of resid- ual clays from limestones is a process of peculiar interest, not only because it has given rise to many large clay deposits, but because certain factors enter into the question which are absent from the decay of igneous rocks and shales. Limestones are composed f essentially of lime carbonate, or of a mixture of lime and magnesium carbonates. Some contain little else than these carbonates, but by far the majority of lime- stones carry appreciable percentages of clayey matter (silica, alumina, and iron) and often other impurities (sulphur, alkalies, etc.). Most of these impurities and particularly the clayey materials are very insoluble, as compared to lime and mag- nesium carbonates. The latter are readily attacked by water carrying dissolved carbon dioxide. When a bed of limestone is permeated by waters so charged, the carbonates of lime and magnesia are carried off in solution, while any clayey matter which may have been contained in the limestone is left behind. Long exposure to such action will result in the removal of a vast amount of limestone, and in the accumulation of a great thick- ness of residual material (clay, chert, etc.), as a mantle over the remnant of the limestone, even when the original limestone * Clays and Clay Industries of Connecticut, pp. 15, 30, 31, etc. t For a more detailed discussion of the composition of limestones, reference should be made to pages 152-155. 228 BUILDING STONES AND CLAYS contained very small amounts (1 to 3 per cent) of such clayey matter. An example may make the case clearer. Suppose that a horizontal bed of limestone 100 feet thick, whose composition is Per cent. Silica 2 Alumina 1| Iron oxide 1 Lime carbonate 95 (this would really be a limestone above the average in purity), were attacked by percolating water, charged with carbon dioxide, Original surface ]- - Thickness of I Limestone ' Removed Jty Solution Residual Clay- Limestone Fig. 28. Formation of residual clay from limestone. the lime carbonate would be removed in solution, while the insol- uble matter would be left behind. In place of the original 100- foot bed of limestone, there would remain a 5-foot bed of clay of approximately the composition, silica 50 per cent, alumina 30 per cent, iron oxide 20 per cent. Now in many cases the con- ditions have been even more favorable to clay formation than in the case supposed, for the original limestones have been both thicker and more impure. Chalk Fig. 29. Residual clays from chalk. The effect of such weathering on an inclined series of chalky limestones is shown in Fig. 27. RESIDUAL CLAYS 229 Another excellent example of a deposit of clay residual from limestone is illustrated in Fig. 28. This shows a section across such a deposit at Bertha, Va. The blocked area in the section is limestone, containing only a very small percentage of clayey matter. By its solution, however, a very great thickness of residual clay is accumulated, and this caps the remaining lime- stone as shown in the figure. A point of particular interest is Surface Fig. 30. Residual clays from limestone. the very irregular form of the base or floor of the clay deposit. It will be seen that the limestone has been dissolved so irregu- larly as to leave pillars and bosses projecting upward into the clay. Such a deposit must of necessity be drilled very carefully in order to determine the available tonnage. Another point brought out by the figures is the sharpness of the transition from clay to unaltered limestone. The whole process is one of solu- tion, so that clays residual from limestone do not show the gradual change downward into the parent rock which is charac- teristic of clays residual from igneous rocks or from shale. Clays derived from the decay of limestones are commonly very fine-grained, and consequently very fat or plastic. The clay itself is apt to be rather low in silica; but the clay deposit frequently contains nodules of chert or flint, or masses (large or small) of iron pyrite or brown iron ore. These materials are as insoluble as the clay, and like it are left behind when the lime- stone is dissolved. On the other hand, the limestone clays do not ordinarily contain sand, gravel, or pebbles. A typical series of such clays is presented below in Table 109, which may be profitably compared with the analyses already given in Table 108. 230 BUILDING STONES AND CLAYS TABLE 109. ANALYSES OF CLAYS RESIDUAL FROM LIMESTONE. l. 2. 3o. 36. Silica (SiO 2 ) 55 42 43 37 42 48 96 Alumina (Al 2 Os) 22 17 25 07 22 26 27 Iron oxide (Fe 2 O 3 ) 8 30 15 16 19 10 53 Lime (CaO) 15 63 29 77 24 Magnesia (MgO) .... 1 45 03 20 69 1 02 Alkalies (K 2 O, Na 2 O) 2 49 3.70 0.80 n.d. Carbon dioxide (CO 2 ) 44 43 n d Water , 9.86 12.98 3.41 9.47 1. Morrisyille Calhoun County, Ala. l 2. Lexington, Va. ) ??' Limestone I Austinville, Va.; Bull. No. 1, Va. Geol. Sur., p. 98. 36. Residual clay ) CHAPTER XV. TRANSPORTED CLAYS. Origin of Transported Clays. The transported clays differ from the residual clays principally in having been moved from the locality at which they were formed, so that their point of deposit may be far from their point of origin. This transpor- tation may have been effected through the agency of running water, of glacial ice, or of the wind. The first of these agents, however, is by far the most common transporting power; ice has moved very few clays, while the effect of wind is in reality a very open question. WATER-BORNE OR SEDIMENTARY CLAYS. According to their point of deposition the sedimentary clays are subdivided into stream, lake, and marine. Marine Clays. The material carried by streams and rivers to the ocean is spread out finally in estuaries, in marshes along the coast line, or as a mantle over the ocean depths. In all these cases the finer material is, of course, carried the farthest, and is deposited only at points where the force of the transporting current is checked. No very sharp line can be drawn between certain classes of marine and stream clays, for clays deposited in the delta of a river, in a broad, shallow estuary or bay, or in marshes along the coast could with much reason be considered fresh-water rather than marine, though in the present volume they are for convenience included with the true marine clays. Marine Clays Proper. Most of the marine clays which are forming at the present day are, of course, unavailable for com- mercial uses, for they are mostly covered by the waters of the ocean. But marine clays formed during earlier geologic periods are of great importance, for earth movements have often elevated the ocean basins or ocean shores so that many marine sediments are now exposed at the earth's surface. Owing to long-continued 231 232 BUILDING STONES AND CLAYS exposure to heat and pressure of the clays so elevated, the older ones have generally become hardened so that they now appear in the form of shales or slates, rather than as ordinary soft plastic clays. The more recently elevated marine clays, however, still retain their softness and plasticity, as is notable in the clay de- posits of the coastal plain. TABLE 110. ANALYSES OF MARINE CLAYS. . 2. 3. Silica (SiO 2 ) 62 80 62 33 61 59 Alumina (A1 2 O 3 )*. 18 23 18 49 19 10 Iron oxide (Fe 2 O 3 , FeO) 6 40 6 91 7 53 Lime (CaO) ... 88 1 00 1 68 Magnesia (MgO) 1 58 1 53 1 87 Potash (K 2 O) 3 05 2 41 n d Soda (Na 2 O) 1.48 2 38 n d. Combined water 4 39 3 81 [ Moisture 1 31 1 11 i 5.51 * Including small percentages of titanic oxide (TiO 2 ). 1. Thomaston, Me. ^ 2. Hayden's Ft., South SW. T. Schaller, analyst. Thomaston, Me. ) 3. Rockland, Me. Shales. It has been noted previously that shales are simply clays which have been hardened by pressure. This statement, while approximately correct, requires some restriction for our present purposes. For shales have been derived almost entirely from extensive deposits of clays of marine origin deposited along seacoasts or in large basins and such marine deposits will naturally differ considerably from glacial, stream, or lake clays. The marine clays have, in general, been transported further than the other types of clay, and have been more effec- tively sorted while in transit. For this reason the shales derived from them rarely show the same irregularities in physical com- position that some modern clays exhibit. Shales, for example, are rarely so full of coarse sand, gravel, limestone fragments, etc., as are the glacial clays of the northern states. Sandy shales and limy shales do occur, it is true, but even in this case such impurities are usually more regularly distributed throughout the mass of the rock than is the case with the impurities of the glacial clays. TRANSPORTED CLAYS 233 The limy shales are almost exclusively shales which occur interbedded, in comparatively thin layers, with limestones. Occasionally a limy shale will owe its content of lime almost entirely to the fossil shell it contains, the remainder of the shale being practically free from carbonates. For both of the above reasons limy shales are apt to be a source of trouble in the practical working of a plant and require considerable care in quarry management to insure that the raw materials are any- where near uniform in composition from day to day. Slates. Slates * are clays or shales which have been so hard- ened and otherwise affected by pressure as to have taken on a regular parallel cleavage, being thus capable of being readily split into thin tough plates. The origin, composition, and dis- tribution of slates have been discussed in detail elsewhere in this volume (Chapter VII). Their interest in the present con- nection is due to the fact that large quantities of waste slate are produced in the operations of quarrying and dressing roofing or mill slate, and that much of this waste could be utilized in the manufacture of clay products. Stream Clays. A stream carrying sediments will deposit a portion of its load at points where its current is checked. This is likely to occur in the broader and shallower reaches of its course, and is particularly frequent when floods have caused the stream to overflow its banks. In this last case the sediment is deposited, levee fashion, par- allel to the course of the stream. In dealing with the clays de- posited along the larger streams, it will frequently be found that pj g 31. Clay terraces, they occur in the form of district terraces, or flat-topped benches, and that often there will be several pairs of such terraces, each at a different elevation. Any one of several causes may have produced this arrangement, but the frequency of the arrangement itself is worth bearing in mind. * It may here be noted that geologists restrict the term slate to clay rocks in which the cleavage has been developed at some angle to the original bedding planes. In common use, however, any shale which breaks into flat and fairly even plates is called a slate, regardless of the direction of the faces of these plates. 234 BUILDING STONES AND CLAYS A very typical set of terrace-clay deposits is shown in Fig. 32, reprinted from the paper by Jones later cited (page 252). The deposits shown in this figure are those occurring along the Hudson River at many points on both of its banks, though in the figure only a few deposits on the east bank are presented. TABLE 111. ANALYSES OF STREAM CLAYS. Silica (SiO,). Alumina I JS,?? de8 (AW),). (F F ^ Lime (CaO). Mag- nesia (MgO). Potash (K 2 O). Soda (NajO) Carbon Corn- dioxide bined (CO 2 ). water. 1 52.73 22.25 7.69 1.48 3.20 4.28 2.22 4.91 2 50.33 27.06 4.91 1.22 3.34 4.40 1.78 5.24 3 55.27 20.52 6.89 2.21 2.80 3.43 2.82 5.06 4 51.10 17.65 6.47 7.45 0.87 n.d. n.d. n.d. n.d. 5 50.60 21.00 7.35 3.75 0.96 n.d. n.d. n.d. n.d. 6 59.81 22.00 4.35 2.29 n.d. n.d. n.d. 7.89 1. South Windsor, Conn, 2. West Hartford, Conn. 3. Newfield, Conn. 4. Coeyman's Landing, N. Y. 5. Catskill, N. Y. 6. Barrytown, N. Y. W. T. Schaller, analyst; Bull. 4, Conn. Geol. Sur., p. 59. Bull. 35, N. Y. State Museum. p. 705. p. 702. p. 702. Lake Clays. Streams flowing into lakes or ponds tend to deposit their sediment at the point where their flow is checked. In small lakes, therefore, the heavier sediments are commonly deposited where the stream enters the lake, while the drier clayey deposits occur a little further off shore. In lakes large enough to be seriously affected by wind and current action, the distribution and character of the clay deposits are closely similar to those of marine clays. Ice-borne or Glacial Clays. The finer material transported by glacial ice, and deposited along or near the margin of the gla- cier, often forms clay deposits of commercial importance. Owing to the purely mechanical origin of clays of this type, they com- monly contain fragments of limestone, sand, pebbles, etc., which limit their use to the manufacture of low-grade products. Wind-borne or Eolian Clays. Many geologists consider that the vast deposits of loess which border the Mississippi and other great rivers are of eolian origin, the material having been trans- ported by the wind. Brockway W.E. Verplanck o E.I. E.2. E.3. E.4. .5. E.l. E.2. .3. E.4. .5. Legend taml tyZft. Yellow Clay g^3 Blue Clay Om Blue Clay & Quick Sand ^_. __^ l^a Rock W.2 s ,j Horizontal, 1=685 ft. (Vertical. 1 = 137 ft. Fig. 32. Clay terraces along Hudson River. (C. C. Jones.) [235] . | E.l. .2. E.8. E.4. E.5. 236 BUILDING STONES AND CLAYS The loess clays from various points along the Mississippi are strikingly uniform in composition, the range of the principal elements being slight. The following series of analyses illustrate this point. TABLE 112. ANALYSES OF LOESS CLAYS. I. 2. 3. 4. 5. 6. Silica (SiO 2 ) . . 72 00 71 11 74 39 73 80 73 92 67 92 Alumina (AUOs) 11 97 11 62 12 03 13 19 11 65 11 76 Iron oxide (Fe 2 O 3 ) 3 51 3 90 4 06 3 43 4 74 6 72 Lime (CaO) 1 80 2 37 1 50 86 1 43 1 63 Magnesia (MgO) 1.35 1.47 1 53 68 60 1 18 Alkalies (K 2 O, Na 2 O) 3 25 3 14 3 01 2 94 3 13 3 79 Combined water . . 6 42 6 71 3 17 5 26 3 08 5 36 Specific gravity 2.17 2.20 2.09 2.17 1.98 1. Kansas City. 2. Boonville. 3. Jefferson City. 4. Hannibal. 5. St. Louis. 6. Gladbrook, Iowa. List of References on Origin of Clays: Barus, C. On the thermal effect of the action of aqueous vapor on feldspathic rocks (kaolinization). School of Mines Quarterly, vol. 6, pp. 1-24. 1885. Bulman, G. W. Underclays: a preliminary study. Geol. Mag., new series, decade III, vol. 9, pp. 351-361. 1892. Cook, G. H. Report on the clay deposits of New Jersey, 1878, pp. 267-306. Cushman, A. S. On the cause of the cementing value of rock powders and the plasticity of clays. Jour. Amer. Chem. Soc., vol. 25, pp. 451-468. 1903. Hopkins, T. C. A short discussion of the origin of the coal measures fire clays. Amer. Geol., vol. 28, pp. 47-51. 1901. Hopkins, T. C. Fire clays of the coal measures. Mines and Minerals, vol. 22, p. 596. 1902. Hopkins, T. C. Kaolin: its occurrence, technology, and trade. Min. Ind., vol. 7, pp. 148-160. 1899. Hutchings, W. M. Further notes on fire clays, etc. Geol. Mag., new series, decade III, vol. 8, pp. 164-169. 1891. Hutchings, W. M. Rutile in fire clays. Geol. Mag., new series, decade III, vol. 8, pp. 304-306. 1891. Hutchings, W. M. Notes on sediments dredged from the English lakes. Geol. Mag., new series, decade IV, vol. 1, pp. 300-302. 1894. Irving, R. Kaolin in Wisconsin. Trans. Wis. Acad. of Sci., vol. 3, pp. 3-30. 1876. TRANSPORTED CLAYS 237 Johnson, S. W., and Blake, J. M. On kaolinite and pholerite. Amer. Jour, of Sci., vol. 43, p. 351. 1876. Merrill, G. P. A Treatise on Rocks, Rock-Weathering, and Soils, 8vo, 411 pages, Macmillan & Co., New York. 1897. Merrill, G. P. What constitutes a clay. Amer. Geol., vol. 30, pp. 318- 322. 1902. Orton, E. The clays of Ohio, their origin, composition, and varieties. Rep. Ohio Geol. Sur., vol. 7, pp. 45-68. 1893. Ries, H. The origin of kaolin. Trans. Amer. Ceramic Soc., vol. 2. 1900. Wheeler, H. A. Clay deposits of Missouri. Rep. Missouri Geol. Sur., vol. 11, pp. 17-27, 49-114. 1896. CHAPTER XVI. DISTRIBUTION OF CLAYS. Geographic Distribution of Clays. In a volume of this size little of value can be said concerning the local distribution of clays, but a few general statements will be made which may serve as a guide to exploration or to further study of the matter. Certain large areas can at least be roughly defined, within each of which areas a certain class of clay predominates. If the reader desires details regarding the distribution of clays in any particular state, or smaller area, reference should of course be made to the reports listed on pages 24Q-243. The glaciated area lies to the north of the line which marks the extreme southern limit attained by the great N ice sheets. North of this line the bedrock was swept clear of all its over- lying de*bris by the glaciers, and except in a few instances no large amount of postglacial decay has occurred. Residual clays are therefore practically lacking in the glaciated area. The coastal plain is the term applied by geologists and physiog- raphers to the great belt of lowland that, from New York City southward, borders the Atlantic and Gulf coasts. Its eastern and southern limits are, of course, the shores of the Atlantic and the Gulf of Mexico. Its western and northern limits may be located closely by tracing a line from New York City through Trenton, Philadelphia, Baltimore, and Washington. The clays of the coastal plain are mostly of marine origin, having been deposited at a time when the coast line was just inland of their present location. They are therefore more widely distributed than glacial or stream clays and their general char- acter and location can usually be predicted, with some certainty, in advance of actual exploration. The coastal plain clays are usually quite siliceous, and low in lime, magnesia, and alkalies. They furnish pottery, stoneware, and firebrick clays, the pottery clays of New Jersey and the 238 DISTRIBUTION OF CLAYS 239 Fl -2 11 'i D 240 BUILDING STONES AND CLAYS stoneware clays of northern Mississippi and western Tennessee and Kentucky being worthy of special note. In the elevated Piedmont and Appalachian regions which lie inland of the Coastal Plain, the decay of igneous and meta- morphic rocks has given rise to bodies of residual clays. These differ in size and grade according to the rocks from which they are derived. The region northwest of the Blue Ridge (and its northern and southern continuations) is covered by old sedimentary rocks sandstones, limestones, and shales. Here again a distinction is to be made between the regions north and south of the glacial border. In the great Appalachian Valley which parallels the western flank of the Blue Ridge or Appalachian range, deep weathering of limestone and shale beds has given rise to heavy deposits of residual clay, particularly south of the glacial limit. The plateau west of the Great Valley yields chiefly shales, varying widely in their character and commercial value. List of References on the Distribution of Clays and Shales. The literature of clays is so extensive that the descriptive papers in the following list have been arranged by States in alphabetical order. General United States: Ries, H. The clays of the United States east of the Mississippi River. Professional Paper No. 11, U. S. Geol. Sur., 289 pp. 1903. Alabama: Ries, H., and Smith, E. Preliminary report on the clays of Alabama. Bull. 6, Ala. Geol. Sur., 220 pp. 1900. Arkansas: Branner, J. C. The cement materials of southwest Arkansas. Trans. Am. Inst. Min. Engrs., vol. 27, pp. 42-63. Branner, J. C. The clays of Arkansas. Bull. No. , U. S. Geol. Sur. (In press.) California: Johnson, W. D. Clays of California. 9th Ann. Rep. Cal. State Min., pp. 287-308. 1890. Ries, H. The clay- working industry of the Pacific Coast States. Mines and Minerals, vol. 20, pp. 487-488. 1900. Colorado: Lakes, A. Gypsum and clay in Colorado. Mines and Minerals, vol. 20. December, 1899. Ries, H. The clays and clay-working industry of Colorado. Trans. Am. Inst. Min. Engrs., vol. 27, pp. 336-340. 1898. DISTRIBUTION OF CLAYS 241 Florida: Memminger, C. J. Florida \kaolin deposits. Eng. and Min. Jour., vol. 57, 436 pp. 1894. Vaughan, T. W. Fuller's earth deposits of Florida and Georgia. Bull. 213, U. S. Geol. Sur., pp. 392-399. 1903. Georgia: Ladd, G. E. Preliminary report on a part of the clays of Georgia. Bull, 6A, Ga. Geol. Sur., 204 pp. 1898. Vaughan, T. W. Fuller's earth deposits of Florida and Georgia. Bull. 213, U. S. Geol. Sur., pp. 392-399. Indiana: Blatchley, W. S. A preliminary report on the clays and clay industries of the coal-bearing counties of Indiana. 20th Ann. Rep. Ind. Dept. Geol. and Nat. Res., pp. 24-187. 1896. Blatchley, W. S. Clays and clay industries of northwestern Indiana. 22d Ann. Rep. Ind. Dept. Geol. and Nat. Res., pp. 105-153. 1898. Iowa: Beyer, S. W., and others. Clays and clay industries of Iowa. Vol. 14, Rep. Iowa Geol. Sur., pp. 27-643. 1904. Kansas: Prosser, C. S. Clay deposits of Kansas. Min. Res. U. S. for 1892, pp. 731-733. 1894. Kentucky: Crump, H. M. The clays and building stones of Kentucky. Eng. and Min. Jour., vol. 66, pp. 190, 191. 1898. Louisiana: Clendennin, W. W. Clays of Louisiana. Eng. and Min. Jour., vol. 66, pp. 456, 457. 1898. Ries, H. Report on Louisiana clay samples. Rep. La. Geol. Sur. for 1899, pp. 263, 275. 1900. Maryland: Ries, H. Report on the clays of Maryland. Rep. Md. Geol. Sur., vol. 4, pt. 3, pp. 203-507, 1902. Massachusetts : Whittle, C. L. The clays and clay industries of Massachusetts. Eng. and Min. Jour., vol. 66, pp. 245, 246, 1898. Michigan: Ries, H. Clays and shales of Michigan. Rep. Mich. Geol. Sur., vol. 8, pt. 1, 67 pp. 1900. Minnesota: Berkey, C. P. Origin and distribution of Minnesota clays. Am. Geol., vol. 29, pp. 171-177. 1902. Mississippi: Crider, A. F. Clays of Mississippi. Bull. 1, Miss. Geol. Surv. Eckel, E. C. Stoneware and brick clays of western Tennessee and north- western Mississippi. Bull. 213, U. S. Geol. Sur., pp. 382-391. 1903. 242 BUILDING STONES AND CLAYS Missouri: Wheeler, H. A. Clay deposits of Missouri. Rep. Mo. Geol. Sur., vol. 2, 622 pp. 1896. Montana: Rowe, J. P. The Montana clay industry. Brick, vol. 24, pp. 1-3. Jan., 1906. Nebraska: Gould, C. N., and Fisher, C. A. The Dakota and Carboniferous clays of Nebraska. Ann. Rep. for 1900, Neb. Bd. of Agric., pp. 185-194. 1901. New Jersey: Cook, G. H., and Smock, J. C. Report on the clay deposits of New Jersey. N. J. eol. Sur., 381 pp. 1878. Ries, H., Kiimmel, B., and Knapp, G. N. The clays and clay industries of New Jersey. Final Rep. State Geol., N. J., 8vo., vol. 6, 548 pp. 1904. New York: Jones, C. C. A geologic and economic survey of the clay deposits of the lower Hudson River Valley. Trans. Am. Inst. Min. Engrs., vol. 29, pp. 40-83. 1900. Ries, H. Clays of New York. Bull. 35, N. Y. State Museum, 455 pp. 1900. North Carolina: Holmes, J. A. Notes on the kaolin and clay deposits of North Carolina. Trans. Am. Inst. Min. Engrs., vol. 25, pp. 929-936. 1896. Ries, H. Clay deposits and clay industry in North Carolina. Bull. 13, N. C. Geol. Sur., 157 pp. 1897. North Dakota: Babcock, E. J. Clays of economic value in North Dakota. 1st Rep. N. D. Geol. Sur., pp. 27-55. 1901. Ohio: Orion, E. The clays of Ohio and the industries established upon them. Rep. Ohio Geol. Sur., vol. 5, pp. 643-721. 1884. Orton, E. The clays of Ohio: their origin, composition, and varieties. Rep. Ohio Geol. Sur., vol. 7, pp. 45-68. 1893. I Oregon: Ries, H. The clay-working industries of the Pacific Coast states. Mines and Minerals, vol. 20, pp. 487-488. 1900. Pennsylvania : Hopkins, T. C. Clays of western Pennsylvania. Appendix to Ann. Rep. Pa. State Coll. for 1897-98, 184 pp. 1898. Hopkins, T. C. Clays of southeastern Pennsylvania. Appendix to Ann. Rep. Pa. State Coll. for 1898-99, 76 pp. 1899. Hopkins, T. C. Clays of the Great Valley and South Mountain areas. Appendix to Ann. Rep. Pa. State Coll. for 1899-1900, 45 pp. 1900. Woolsey, L. H. Clays of the Ohio Valley in Pennsylvania. Bull. 225, U. S. Geol. Sur., pp. 463-480. 1904. DISTRIBUTION OF CLAYS 243 South Carolina: Sloan, E. A preliminary report on the clays of South Carolina. Bull. 1, S. C. Geol. Sur., 171 pp. 1904. South Dakota: Todd, J. E. The clay and stone resources of South Dakota. Eng. and Min. Jour., vol. 66, pp. 371. 1898. Tennessee: Eckel, E. C. Stoneware and brick clays of western Tennessee and northwestern Mississippi. Bull. 213, U. S. Geol. Sur., pp. 382-391. 1903. Texas: Kennedy, W. Texas clays and their origin. Science, vol. 22, pp. 297- 300. 1893. Washington: Landes, H. Clays of Washington. Rep. Washington Geol. Sur., vol. 1, pt. 2, pp. 13-23. 1902. Wisconsin: Buckley, E. R. The clays and clay industries of Wisconsin. Bull. 7, Wis. Geol. Sur., 304 pp. 1901. Irving, R. Kaolin in Wisconsin. Trans. Wis. Acad. Sci., vol. 3, pp. 3- 30. 1876. Wyoming: Knight, W. C. The building stones and clays of Wyoming. Eng. and Min. Jour., vol. 66, pp. 546, 547. 1898. CHAPTER XVII. FIELD EXAMINATION OF CLAY DEPOSITS. THE data obtained in the course of a field examination should cover the amount of clay present, its character from a techno- logic point of view, and such other features (drainage, stripping, transportation) as will affect the commercial value^of the deposit. These field data will of course have to be supplemented] by lab- oratory tests on the samples obtained. The engineer called upon to examine and report upon a clay property will do well to realize that the problem before him is one which properly falls largely within the domain of applied geology. The form and extent of the clay deposits are, it is true, determined by engineering means, but the proper inter- pretation of the data afforded by the pits, trenches, or drill holes will usually require a working knowledge of general geologic principles. These principles are not difficult to understand, nor are they hard to apply. The subject of field examination might naturally be divided into two parts: (1) the purely mechanical portion, relating to methods of drilling, boring, etc., and (2) the geologic portion, relating to the interpretation of the data so obtained, for this is the order in which any particular piece of work would be taken up. But in discussing the subject it is more convenient to almost reverse this arrangement, by describing first the general conduct of the work, and then taking up the methods of getting the data. THE GENERAL CONDUCT OF FIELD WORK. The Use of Geological Reports. Before taking the field it is advisable to find out whether or not geological reports on the district have been published. The federal government and most states support geological surveys, and in many cases it will be found that these organizations have published more or less complete reports on either the general geology or the clay re- 244 FIELD EXAMINATION OF CLAY DEPOSITS 245 sources of the district which is to be examined in detail by the engineer. Many such reports are listed on pages 240-243 of this volume. The help to be gained from these geological reports will depend largely on the state in which the deposit is located. Very detailed and generally satisfactory reports on clays have been issued by the states of Alabama, Connecticut, Indiana, Iowa, Maryland, Michigan, Missouri, New Jersey, New York, North Carolina, Ohio, South Carolina, and Wisconsin. Partial or otherwise incomplete reports have been issued for Georgia, Mississippi, North Dakota, Pennsylvania, South Dakota, and Washington. Scattered data of some value are on record for Arkansas, California, Florida, Kansas, Kentucky, Louisiana, and other states. Detailed reports on part or all of the clays of Arkansas, Illinois, Virginia, and Texas are known to be in preparation at the date of writing. These reports vary greatly in their detail and value. Even the poorest of these reports, however, will contain information that will save needless labor. Effect of Kind of Clay on Methods of Work. The material to be reported on may be (1) a hard shale, even on its outcrop; (2) a shale which has weathered so as to appear soft and claylike; (3) an ordinary soft plastic clay, or (4) a residual " kaolin " derived from a mass or dike of decomposed granite or feldspar. Each of these types will present different problems, and may require different ' methods of field work. The importance of first determining the method of origin of the deposit lies in the fact that it influences both the form of the deposit and the character of the material. If the material is merely a soft surface clay, then we may expect to find a flat- lying and basin-shaped deposit, and our only interest in the hard rocks of the region will arise from the fact that they may form the lower boundary and sides of the deposit. But if the material is a shale, the dip and strike of other beds of hard rock will probably prove of interest, for we may fairly expect the shale deposit to agree in these particulars with adjacent beds of limestone, sandstone, etc. 246 BUILDING STONES AND CLAYS A case in point may be cited in which the owner insisted that the ridge in which the clay occurred was composed entirely of high-grade clay a thickness of 800 feet or more being claimed. The statement was inherently improbable, owing to the geologic structure of the region, but the property was visited. A large number of pits had been run in on clay at various elevations on both flanks of the ridge, and a shallow trench had been cut transversely across the top of the ridge. The trench and all the pits showed clay, and the owner pointed to this triumph- antly as proving his statement. Outcrops were scarce, as both top and flanks of the ridge were well covered with soil and tim- ber, but several carefully meas- ured sections, made at various points, when combined showed that the conditions were as in Fig. 35. In place of a solid bed of clay 800 feet thick there were in reality a number of clay Fig. 35.- Interbedded sandstones and beds > one 30 feet thick but shale-clays. most of them varying from 4 inches to 3 feet the total thickness of all the clay beds was not over 60 feet, and the remain- ing 770 feet was sandstone. But the case was even worse than this. In looking over the face cut into the 30-foot clay bed, a number of beds of loose sand were noticed. Careful examina- tion showed that the clays were really the exposed weathered outcrops of a series of shales, that the sands were similarly weathered sandstones, and that consequently when the workings were driven in under cover the owner might expect to find, in place of the 30-foot clay bed exposed at the outcrop, a series of shale beds interbedded with sandstones, and that these shales would probably contain impurities which had been removed by weathering from the clays which showed at the outcrop. Now in this case all this information could have been obtained directly, but only at prohibitive expense, by deep drilling across the ridge. Handling it purely as an engineering problem would have required several months' work and the expenditure of several thousand dollars, while by the application of purely geologic methods of reasoning and field work the same results were secured in less than a day. FIELD EXAMINATION OF CLAY DEPOSITS 247 Examination of Shale Deposits. Shales are mostly of marine origin, and were deposited in extensive water areas. Any given bed of shale is therefore apt to be quite regular both in thickness and in composition, for considerable distances. This materially lessens the labor of the explorer. If on visiting a property he finds, for example, a good outcrop which shows a 30-foot bed of shale underlain by a bed of limestone and overlain by strata of sandstone, he may be fairly sure that this shale bed will probably not vary greatly in thickness or in its associated rocks within the limits of the property. It would be fair to expect that its thickness will not fall below 25 or rise above 35 feet in a quarter mile. It would also be a reasonable expectation and this is a matter of great value that if at some near-by point he finds the limestone outcropping, with perhaps a soil-covered slope above it, trenching above the limestone would reveal the shale in its proper position. An outcrop of the overlying sandstone, on the other hand, would lead the engineer to trench on the slope below it in order to uncover the shale bed. In this connection it is well to recollect that in most of the shale-producing areas of the United States the rocks are lying in an almost horizontal attitude. If a shale bed outcrops in the flank of a ridge, the shale is apt to weather so as to produce quite steep but regular slopes, usually slippery because covered with loose fragments of shale. Sandstone or heavy limestone beds, under similar conditions, would be apt to form very marked terraces or stepped slopes. These conditions are well shown in Fig. 25, which is a drawing to scale. Here a sandstone bed forms the crest of the ridge, a limestone bed forming a very marked terrace about one-third of the way down the slope, while the shale beds above and below the limestone give the usual shale type of topography. These facts are of service in tracing a shale bed throughout a property. Examination of Soft Clay Deposits. The principal difference between deposits of shales and of soft clays, so far as the present connection is involved is (1) that shales vary little in thickness and associated rocks as compared with soft clays; and (2) that shale beds can be followed down under overlying rocks, while most beds of soft clay terminate as soon as hard rock is struck either in the bottom or the sides of a deposit. The only promi- nent exceptions to this rule are the Cretaceous and Tertiary 248 BUILDING STONES AND CLAYS clays of the coastal plain (see pages 238, 239), for though these are soft clays, they are quite regular in thickness and associated strata. In dealing with deposits of soft clays, therefore, greater irregu- larity of form may be expected than when shales are in question, and the work of exploration and examination must be carried on with accordingly greater care. The forms which clay deposits may take are infinite, but two general types may be expected to occur more frequently than the others. These are the bench and the lens. Clays which are deposited along stream or river banks usually occur in the first of these forms, as distinct benches or terraces (see pages 233, 234, and Figs. 31, 32) . Clays which have been found in lakes usually occur in the second form. Dealing with Known Deposits. If the area occupied by the clay deposit is small and fairly well known in advance, it will be sufficient to lay it off in squares 25, 50, or 100 feet on a side; de- termine the elevations at the cor- ners of these squares, and then drill or sink a test pit at each corner. The results of the borings or pits are then to be plotted so as to give two series of cross sections across Fig. 36. Basin or lens, shaped tne deposit at right angles to each clay deposit. other. This is a purely mechanical performance, and little except care is required to carry it out. It is sufficient only in dealing with small deposits, or when the general form, extent and character of the deposit is already well known. Such cases will arise when a brick plant acquires property adjacent to its own clay pits, when new openings are to be run in on a well-known " vein " of fire clay, and in other similar circumstances. For such work it is rarely necessary to lay off the squares with a transit and tape, or to determine altitudes with a Y level. In many cases a pocket compass and pacing will suffice to give direction and distance, while a Locke level can be used for eleva- tion. If the case requires more refinement, the " drainage " and " architects' " levels made by different makers are sufficiently pre- cise for such work and will probably be the best instruments to use. FIELD EXAMINATION OF CLAY DEPOSITS 249 METHODS OF BORING. The earth auger is usually the best and cheapest instrument for determining the thickness of clay deposits and securing samples of the clays at various depths. It consists of an auger attached to one or more lengths of coupled pipe, the upper length of pipe being provided with a T handle. The auger is sunk by turning the handle, and on withdrawing it a sample of the clay is caught on the auger screw. The use of this implement is limited to the clays proper or to very soft shales. Two very detailed descriptions have appeared of work done with the earth auger, and as the two accounts taken together cover very fully the entire range of exploratory work that can be handled economically by the use of the auger, they will be quoted almost in full. The Auger in Light Work. Mr. Charles Catlett has made extensive use of the earth auger in testing brown ore deposits occurring interbedded with clays and sands at rather shallow depths. His description* of outfit and results is as follows: 1. An auger bit of steel or Swedish iron, with a steel point, twisted into a spiral, with an ultimate diameter of 2 inches, and an ultimate thickness of blade of not less than \ inch. The point is found more effective when split. The length of the auger proper was gradually increased until about 13 inches was reached as the apparent maximum which could be used effec- tively. The 13-inch auger contains four turns. This was welded to the end of 18 inches of 1-inch wrought-iron pipe, on which screws were cut for connection. 2. One foot of If-inch octagonal steel, with a 2-inch cutting face, which is likewise welded onto 18 inches of pipe, cut for connections. 3. Ten feet of IJ-inch iron rod, threaded at either end for connection with 1-inch pipe. When connected with one of the drill bits this becomes a jumper for starting holes through hard material. It is also used when desired to give additional weight to the drill in going through rock below the surface. 4. Sections of 1-inch pipe and connections. 5. An iron handle, with a total length of 2 feet, arranged with a central eye for sliding up and down the pipe and with a set screw for fastening it at any point. 6. A sand pump, consisting of 1 or 2 feet of 1-inch pipe, with a simple leather valve and a cord for raising and lowering it. * Trans. Am. Inst. Mining Engrs., vol. 27, pp, 127, 128, 250 BUILDING STONES AND CLAYS 7. Two pairs of pipe tongs or two monkey wrenches, with attachments for turning them into pipe tongs. 8. Sundries: 25 feet of tape, oil can, flat file, cheap spring balance, water bucket, etc. The auger is used by two men, who, standing on opposite sides, turn it by means of the handle. The handle is also useful in giving a good purchase for starting the auger from the bottom of the hole, in opposition to the air pressure, which is considerable. Enough water is continually used to just soften the material. Usually the auger brings up a small portion, which is dry and unaffected. Every few minutes, as the auger becomes full, it is lifted out, scraped off, and replaced. The handle is moved up and tightened by means of the set screw as the auger goes down. At every slight change of the material the depth and the character of the material are recorded. When hard material is encountered the auger bit is screwed off and the drill bit screwed on, thus forming a churn drill, which may be used for passing through the hard material, the auger being replaced when softer material is reached. The churn drill is used by lifting it and letting it fall, turning it slightly each time. Its weight makes it cut quite rapidly. When the drill is used the muck is either worked stiff enough to admit of its being withdrawn with the auger, or it is extracted by means of the sand pump or a hickory swab. In either case the material is washed and a sample is obtained of the stratum through which the drill is cutting. Of course the best work with such tools is done on soft material, but it is entirely practicable to go through hard ma- terial (a few feet of quartzite or flint, and many feet of ore being often encountered in a single hole), and the ability of this simple contrivance to go through interbedded layers of hard and soft substances makes it very efficient. The cost per foot increases considerably with depths exceed- ing 50 feet, but at the greatest depth I attained (some 80 feet) I did not reach either its capacity or the limit of its economical use as compared with other methods. Up to 25 feet two men can operate it; from 25 feet to 35 feet three men are necessary; from that to 50 feet a rough frame, 15 feet to 20 feet high (costing something over $1.00), for the third man to stand on, is required. The frame can be moved from point to point. Above 50 feet it is generally necessary to take off one or two of the top joints each time the auger or drill is lifted. FIELD EXAMINATION OF CLAY DEPOSITS 251 Feet. and gravel 2 Yellow clay 2 Clay with some ore 4 Solid ore 5 White clay and ore 3 Total thickness 16 Sunk by two men in ten hours. B. Loose dirt 3 Blue clay 7 Shale ore 3 Wash ore 9 Shale ore 3 Wash ore 15 Total thickness 40 Sunk by two men in eleven hours plus three men for four hours. C. Yellow clay 12 Black flint f Yellow clay 2| White sand 1 Solid sandstone 2 Total thickness 18 Sunk by two men in five hours. D. Sand and gravel 1 Clay 28 Total thickness 29 Sunk by two men in five hours. E. Yellow Clay , 14 Solid ore 3 Clay 1 Ore 5| Clay 2| Total thickness 26 Sunk by two men in six hours. F. Feet. Sand 1 Shale ore 4 Clay and sand 9 Sandstone 5 Total thickness 19 Sunk by two men in 8 hours. G. Red clay and sandstone 19 Clay 31 Clay and flint 2 Total 52 Two men fifteen hours plus three men four hours. H. Sand and boulders 12 Clay and ore 19 Clay and flint 3 Clay and a little ore 19 Clay and much ore 2 Clay and a little ore 5 Clay 3 63 Two men for five hours plus three men for twenty-five hours. Ft. Hrs. A.. B.. C.. D.. E.. F.. G.. H.. 16 40 18 29 26 19 52 63 20 34 10 10 12 17 42 85 Ft. per hour. 0.80 1.18 1.80 2.90 2.17 1.12 1.24 0.74 263 230 1.14 252 BUILDING STONES AND CLAYS The Auger in Heavy Work. The most extensive use to which the auger has been put in testing clay deposits was probably in the course of the examination of the Hudson River clay deposits carried out some years ago by Mr. C. C. Jones. In this work most of the holes were deep 40 feet or more while some reached over 100 feet. This necessitated certain modifications both in outfit and in the conduct of the work, as is shown in the following description quoted from Mr. Jones' paper* on the subject. In this work each drilling gang was supplied with one 20-foot hoisting gin, one 6-inch block and fall, 100 feet of f-inch rope, 1 differential chain block, two 1 or 2-inch augers, two handles, three pipe wrenches, 12 feet of IJ-inch iron rod, 102 feet of J-inch and inch pipe, in 6 and 12-feet sections, from 20 to 50 feet of 1J or 3-inch pipe for casing, 1 rock drill, chains, etc. The portable hoisting gin was arranged to fold together so as to be used as a platform on which to carry all the pipe, supplies, etc., which were lashed to it by rope. The gin, thus loaded, could be carried by four men. Each drill gang consisted of three men, and the foreman of a group of gangs aided when shifting position. The holes varied in depth from a few feet to over 100 feet. In all, about 150 holes were sunk, each gang averaging one hole per day for the entire time. The gin is made of three pieces of good timber spruce pref- erably 4 inches by 4 inches by 20 feet in size. The top of each piece is chamfered and a bolt is inserted to prevent split- ting. The middle piece is, of course, chamfered on two sides, and the others on the inside only. This is to allow for the spread of the legs of the tripod, or gin, when it is set up. On the chamfered face, below the bolts, a hole is bored in each piece for a f-inch round iron bar to pass freely. The tops of the three timbers, or legs of the gin, are placed together; the bar is inserted through the hole in the first leg, through one eye of the bail, through the hole in the middle leg, through the other eye of the bail, and then through the hole in the third leg. One end of the iron bar is provided with a squared head, and the other with a slot, into which a pin or dowel is driven, after inserting the bar through the third leg. The bail, of f- inch round iron, thus hangs on the bar in the spaces between the legs of the gin. The " drop " of the bail should allow it to pass freely over the top of the middle leg, i.e., the length of the bail * Trans. Amer. Inst. Mining Engrs., vol. 29, pp. 40-83. FIELD EXAMINATION OF CLAY DEPOSITS 253 8 I 254 BUILDING STONES AND CLAYS should exceed the distance from the bar to the top of the timber. Sufficient play should be given in all these parts to have them fit loosely, and washers should be used to protect the wood. Cleats are nailed to the middle leg of the gin to form a lad- der to the top when erected. To erect the gin the middle leg- is turned about the bolt as a hinge, until it again lies on the ground. Three men grasp each a leg of the gin, and by push- ing towards the bail raise it in a minute. This single maneuver suffices to erect the gin over an exact point. To dismount it the middle leg is simply carried out until the gin is lowered to the ground; this leg is swung back over the bolt again and thus forms the platform upon which everything is carried forward by a single trip, as above described, to the next point of operation. As soon as the gin has been erected, one man ascends the ladder and hooks the wooden block over the bail, and the fall is plumbed over the exact point for the bore hole. This is an important particular, to insure always a vertical stress in withdrawing the auger. The rope and fall are now caught up on one of the cleats to the side. The auger is made from an ordinary wood auger with 2-inch cutting face, which is welded to a short piece about 18 inches of black pipe, on one end of which a thread is cut. This makes the bit about 3 feet along. The handle is about 2 feet long over all, and is made of two pieces of f-inch round iron, welded to a strong cylindrical ring, which will pass freely over couplings for 1-inch black pipe. The ring is provided with a strong | by 2J-inch set screw, for securing the handle to the pipe. The differential chain block is Yale and Towne's J-ton capacity, single-chain. Stillson pipe wrenches are used, two 18-inch and one 14-inch, and a small monkey wrench is required for the set screw. The section of IJ-inch iron rod has threads cut at each end for 1-inch pipe couplings. The five 12- foot sections and seven 6-foot sections of 1-inch pipe have threads cut at each end for couplings. Each section is provided with a coupling at one end, and it is good practice to have a string of extra couplings on hand. The lj-inch or 3-inch pipe for casing is in 4-feet or 5-feet sections, with threads cut at each end for couplings. This casing is driven down when troublesome sand or gravel is encountered near the surface. As a rule it is little employed; but in some localities it is an absolute necessity. The drill is 18 inches long with a 2-inch cutting face, and: a thread cut at the other end for 1-inch couplings. It is made from IJ-inch octagon steel. The chains, of f-inch iron, with short links, are 3 feet long, and have heavy rings at one end and hooks at the other. An oil can and a small file, both for couplings, about complete the outfit for each boring gang. In addition to this, a single outfit complete, exactly like the foregoing, but made of J-inch pipe, the auger and drill having FIELD EXAMINATION OF CLAY DEPOSITS 255 1-inch cutting face, will be found indispensable. This can be taken from gang to gang as required. It sometimes happens that a bore hole made by the larger apparatus becomes unex- pectedly obstructed (say, at 50 to 70 feet) by a pebble, a coup- ling accidentally dropped in, or some other unfortunate cause, and all efforts at progress fail. This smaller apparatus can then oiten be successfully employed to pass the obstacle and com- plete the test. In commencing operations, an auger is attached to a 12-foot section, the handle is adjusted, and boring is begun at a des- ignated point, great care being taken to start vertically, and to preserve the original orifice. Neither more nor less than five turns of the auger are required. This fills the bit, which is then drawn to the surface. One man is always required to attend to the bit, as it enters or emerges from the hole an insignificant but important duty. As the hole deepens additional sections are attached, until the assistance of the gin is required. At this period, after the auger has received the prescribed number of turns, the set screw in the handle is loosened and the handle is allowed to drop to the ground. A 3-foot chain is passed around the pipe, the hook being passed through the ring to form a run- ning noose; the hook is attached to the fall, and stress is applied. After lifting the pipe to a convenient height it is gripped at the ground, either with a wrench or by simply tilting one end of the handle so that the ring binds against the pipe. The stress is released on the chain as soon as the pipe is held by the grip and the chain slipped down for a fresh hold, continuing in this manner until the auger has been completely extracted. When the depth reaches 30 feet, the column of pipe must be disconnected at that point. To expedite this procedure, a 3-foot chain is looped, hook and ring, and loosely dropped around the top of the gin. As the pipe is withdrawn from the hole it is so directed at the top as to enter this loop. After withdrawing the six sections as above described, the handle is attached again below the lowest coupling (where it already lies in place), the 30-foot length is unscrewed, and being held upright by the loop at the top of the gin is merely set at one side. The chain on the fall is again attached to the pipe above the handle, a stress applied to the rope, the handle loosened as before, and this process is continued for each 30-foot length until the auger has been withdrawn from any depth; the invariable rule being to have always either the handle or the chain under stress below a coupling attached to the pipe, while the auger remains in the hole. This operation is reversed to lower the pipe again into the hole, i.e., the sections are replaced in the order of their removal. It follows that the depth of the hole at any time can be ascertained from the number of sections in use. At depths exceeding 75 feet (frequently less), the chain block must be used to start the auger, hooking it on 256 BUILDING STONES AND CLAYS to the wooden fall when required. In this manner, with a little training and a proper division of the duties of each man in the gang, the boring becomes practically continuous, and proceeds very rapidly. One hundred feet of pipe can be started, pulled up, disconnected, the auger bit cleaned, and the whole apparatus let down into the hole again in a few minutes. When sand is encountered, enough water to make it adhesive must be poured into the hole, and the auger will then carry it to the surface. Thin strata of sand cause difficulty, and, simi- larly, fine gravel is frequently impenetrable. For holes of this size the various sand-pump devices are failures, and the auger alone will do the work better. The drill, with or without the iron-rod section, offers the readiest solution to the gravel ques- tion. Gravel must be broken up 6r pushed to one side. The knack of manipulating the drill to meet these circumstances can only be imparted by experience. The best plan is to instruct practically the foreman alone, who must then deal personally with the difficulty when it arises. Quicksand is another great obstacle to deep boring. If the quantity of water is small, and the stratum thin, it is occasionally possible to penetrate it by very rapid work, and bore to the depth required for a given purpose; but a thick seam is impene- trable by the auger, on account of the closing up of the hole through the vacuum created by withdrawing the auger, or by the pressure of superincumbent masses. Casing will not over- come this difficulty. Ordinarily, and especially in test boring in clays, it is unnecessary to penetrate quicksands. A long chapter could not fully treat the subject of accidents. A general rule other than an exhortation to patience is out of the question, because of the variety of these seemingly trifling mishaps. Grappling devices to remove accidental obstacles in a bore hole are all excellent in theory, but the simplest devices often succeed where the more elaborate fail. A section of pipe becoming disconnected in the bore hole can be caught up by using the disjointed member provided with a clean, freshly-oiled coupling; a coupling can often be removed from a hole by using a taper-pointed stick driven into the end of the pipe; an auger broken at the shank may be grasped by a noose of short-link chain lowered by two strings, which is then grappled by a hook on the end of the i-inch rod or pipe, or entangled around the small drill. Most of the mishaps happen through neglect of the simple rules given. It is important always to avoid gorging the auger at great depths. It is apt to be frequently clogged at the bottom of a long column of pipe, and it is not advisable to then reverse the auger to release it. FIELD EXAMINATION OF CLAY DEPOSITS 257 References on Methods of Field Examination. Bleininger, A. V. The manufacture of hydraulic cements. Bull. 4, Ohio Geol. Survey, 1904. See pp. 102-108. Catlett, C. The hand-auger and hand-drill in prospecting work. Trans. Amer. Inst. Mining Engrs., Vol. 27, pp. 123-129. 1898. Darton, N. H. On a jointed earth-auger for geological exploration in soft deposits. American Geologist, Vol. 7, p. 117. 1891. Jones, C. C. A geologic and economic survey of the clay deposits of the lower Hudson River Valley. Trans. Amer. Inst. Mining Engrs., Vol. 29, pp. 40-83. 1900. Determination of Composition and Tonnage. Errors in Sampling. In sampling clays from a natural out- crop, or even from an artificial cut which has stood for any length of time, it must be borne in mind that there are two dis- tinct opportunities for serious error. The first is due to purely physical causes, and arises from the very yielding nature of clays when exposed for a time to atmos- pheric action. Parts of the face of the outcrop or cut r are likely to have slipped down considerably, so that the exposure does not represent the true character of the clay. The second chance for error arises from the fact that, when clays or shales are exposed to the action of rain or surface waters for any length of time, the surface clay will be robbed of its more soluble or changeable constituents. The outcrop is, therefore, likely to show lower percentages of lime, magnesia, alkalies and sulphur than the same clay body carries in depth. A sample taken from the outcrop might, on analysis, show a refractory clay practically free from these fluxing constituents, while ten or fifteen feet below the outcrop the fresh clay might contain so much lime, alkalies, etc., as to be of very inferior grade. The analyses quoted below illustrate very clearly the differences which may be expected to occur between fresh unweathered clay and the clay as it outcrops. Both the analyses quoted are of clays from Croton Point, New York. It will be seen that the blue unweathered clay (A) contains more than twice as much lime as the yellow weathered clay (B). Weathering has also slightly reduced the magnesia, and has affected the alkalies very markedly. The insoluble constituents silica, alumina and iron are in consequence of this leaching relatively increased in the weathered clay. 258 BUILDING STONES AND CLAYS A. B. Silica (SiO). 51 61 56 75 Alumina (A^Oj 19 20 20 15 Iron oxide (Fea O 3 ) 8 19 8 82 Lime (CaO) 7 60 3 14 Magnesia (Mg( )) 1 25 1 20 Alkalies (K 2 O, Na 2 O) . . . 5 32 4 50 Carbon dioxide (CO,) I Sen Water \ 7.25 .4MB Estimation of Tonnage. On ihe pages immediately follow- ing several long series of tests of the specific gravity and weights of a large number of clays and shales are quoted and discussed. From the data there given the following rules can be considered (1) Ordinary soft clays will average 120 pounds per cubic foot, or 3240 pounds per cubic yard, in the bank. (2) Shales will average 150 pounds per cubic foot, or 4050 pounds per cubic yard. For rough calculations as to tonnage, it may, therefore, be assumed that clays will weigh If tons, and shales 2 tons, per cubic yard. Prof. G. H. Cook, in 1874, determined* the specific gravity of a large series of clays from New Jersey. In making this deter- mination " a prism about an inch in length was cut out of the solid mass. This was covered by a film of paraffin and weighed, first in air, then in water." The values thus obtained are, there- fore, close approximations to the density of the clay as it occurs in nature, and when multiplied by 62.4 will give the weight per cubic foot of the product in the bank. The values varied from 1.539 to 2.170, the average of the 86 samples of unwashed clays being 1.824. Converted into pounds per cubic foot, these values are as follows: Specific grav- ity. Pounds per cubic foot. IMaximum 2 170 135 41 Average 1.824 113.82 Minimum .... 1.539 96.03 * Report on the Clay Deposits of New Jersey, 1878, pp. 283-286. FIELD EXAMINATION OF CLAY DEPOSITS 259 Part of this great variation in density was due to the variations in furnaces, etc., but much of it was directly traceable to the varying percentages of sand contained in the clays. The table following illustrates this point. TABLE 113. RELATION BETWEEN SPECIFIC GRAVITY AND SAND PERCENTAGES. (CooK.) Specific gravity. Per cent of sand. Specific gravity. Per cent of sand. 2.321 58.40 1.607-1.612 8.60 2.283 57.10 1.743-1.789 6.51 2.052-2.101 56.80 1.657-1.705 3.10 2.047-2.077 48.40 1.764-1.769 1.10 1.981-2.023 40.50 1.766-1.893 0.80 1.971-2.138 39.95 1.528-1.542 0.71 2.012-2.022 37.85 1.738 0.70 2.129-2.151 37.10 1.731-1.809 0.50 1.994-2.047 28.81 1.578-1.610 0.50 1.705-1.732 27.80 1.723-1.742 0.20 1.861-1.864 20.60 In 1896 Wheeler reported the specific gravities of a series of 153 Missouri clays, of several widely different types. His re- sults, grouped by classes, are given in the following table. TABLE 114. SPECIFIC GRAVITY OF MISSOURI CLAYS. (WHEELER.) i ype 01 ciay. Minimum. Average. Maximum. Kaolins (residual) 1.69 1.90 2.02 Loess clays 1 69 2 05 2 17 Gumbo clays 1 98 2 01 2 05 Tertiary clays 1 93 2 03 2 13 Fire clays (shales) 2 23 2 40 2 54 Nonrefractory shales. 2 15 2 38 2 56 Specific gravity. In recent clay investigations* carried on by the New Jersey Geological Survey a series of 31 clay samples were tested for specific gravity. In this case the clays were powdered, and the specific gravity was then determined by the use of the pycnom- eter. Since this method disregards the air spaces in the clay, and really gives the specific gravity of the mineral particles, the results, as might have been expected, gave much larger values than * Vol. VI, Reports New Jersey Geol. Survey, p. 115, 1904. 260 BUILDING STONES AND CLAYS those reported by Cook. The minimum specific gravity found was 2.39; the highest, 2.84; while the average for the 31 samples was 2.584. A similar series of 32 Iowa clays gave* a minimum value of 2.25; a maximum, 2.64; and average, 2.46. For the purposes of the engineer or manufacturer, these Iowa and the later New Jersey attempts to determine the " true specific gravity " of clays may be disregarded entirely; for the values found by this method are not of the slightest economic importance. Neither engineer nor manufacturer has any interest in knowing the " true specific gravity " of a clay in a state of theoretically maximum density, free from all air spaces; for such clays do not occur in nature. What we do want to know is the weight per cubic foot of clay as it occurs in the clay bank, and fortunately the older work of Cook and Wheeler gives the desired information. The two sets of results (Cook and Wheeler), when combined and divided merely into the two natural groups of (1) ordinary clays and (2) hard shales, give the following results: TABLE 115. SPECIFIC GRAVITY AND WEIGHT OF CLAYS. Kind. Specific gravity. Weight in pounds per cubic foot. Mini- mum. Aver- age. Maxi- mum. Mini- mum. Aver- age. Maxi- mum. Clay 1.539 2.15 1.90 2.39 2.17 2.56 96 134.2 118.6 149.1 135.4 161.7 Shale These figures may, therefore, be used in calculations. For convenience it may be considered, without sensible error, that a cubic foot of clay, in the bank, will average 120 pounds, while a cubic foot of shale will average 150 pounds. Vol. XIV, Reports Iowa Geol. Survey, p. 116. INDEX Abrasion tests, 216. Absorption tests, 198-202, 203. Acid rocks, 9, 23. Acid tests, 207-210. Albite, 25. Amphibole, 27, 34. Analyses: average igneous rocks, 8, 23. granite, 43. limestone, 8, 154. sandstone, 8, 128. shale, 8, 98. slate, 8, 97. basic rocks, 224. feldspars, 26. granites, 43-55. hornblende, 28. kaolinite, 222. limestone clays, 230. limestones, 155-156. loess clays, 236. marbles, 169-171, 178. marine clays, 232. micas, 27. pholerite, 222. residual clays, 223, 224, 227. sandstones, 131-136. serpentine, 83-84. shale clays, 225. shells, 151. slates, 8, 97, 99, 100, 103-108. stream clays, 234. trap, 72-76. Anorthite, 25. Anticline, 13. Ash slates, 99-100. Ash, volcanic, 20-21, 128. Auger, earth, 249-257. Augite, 27, 34. Basalt, 30, 70. Basic rocks, 9, 23, 70-80, 81-90, 224. Batholith, 19. Bedding, 93. Bibliographies (see reference list). Biotite, 26, 34. Bluestone, 144, 146. Bond issues, 190-193. Bosses, igneous, 19. Brard test, 205-207. Breccia, 137. Calcareous tufa, 157. Calcite, 154. Cementing materials of sandstones, 137. Chalk, 157. Chemical composition (see analyses). Chemical relation of rock, 7. Chert, 153, 157. Chlorite, 28. Cleavage of slates, 110-111. Coastal Plain clays, 238-240. Color of granites, 35. limestones, 156. marbles, 177. slates, 108-110. stone, 186. trap, 79. Composition, chemical (see analyses). Compressive strength, 214-215. granites, 55-60. limestones, 158-159. marbles, 172-173. sandstones, 139-142. serpentines, 85-86. traps, 77. Cone, volcanic, 20. 261 262 INDEX Conglomerate, 137. Costs, stone industry, 190-191. Density (see specific gravity). Diabase, 70. Diamond-drill work, 183-184. Dike, 20. Diorite, 29, 70, 224. Dip, 11. Dolomite, 152. Dressing of slate, 115-119. Earth history, 1. Earth auger, 249-257. Elseolite, 34. Elevation of land, 2. Engineering geology, 1. Examination of clay properties, 244- 260. Examination of stone properties, 182- 194. Expansion of stone, 202. Faults, 13. Feldspar, 25, 34. Feldspar, decay of, 221-223. Felsite, 30. Financing stone industry, 189-194. Fire resistance, 210-217. Flagstones, 143. Flint, 153. Folds in rock, 12. Frost tests, 203-207. Gabbro, 29, 70. Geologic ages, 3, 4. Geologic chronology, 3. Glacial clays, 234. Glacial limit, 238. Glacial period, 2. Glass, volcanic, 21, 30. Gneiss, 22, 30, 37. Grain (in granite), 15, 39. Grains, size of, 37, 137, 185. Granite, 29-69. Gravel, 10, 127. Gravity (see specific gravity). Graywacke, 143. Hardness of stone, 216. Heat resistance, 210-214. Hornblende, 27, 82. Hornblendite, 29, 70. Ice-borne clays, 234. Igneous action, 17. Igneous rocks, 5, 17-90. Igneous slates, 99-101. Impact tests, 112. Intrusives, 17. "Isinglass," 26. Joints, 14, 186. Kaolinite, 222. Laboratory tests of stone, 195-217. Labradorite, 25. Laccolith, 19. Lake clays, 234. Laminated igneous rocks, 22, 37. Lava, 20, 31. Limestones, 150-165, 227-230. Loess clays, 234, 236. Magnesia and limestones, 152. Marbles, 157, 166-181. Marine clays, 231-232. Marl, 157. Mass of igneous rocks, 22. Metamorphic rocks, 6, 11, 93, 95-96, 113. Mica, 26, 34. Microcline, 25. Mille (of slate), 120. Minerals in granite, 34, 36. Minerals in trap, 71. Minerals, rock-forming, 25. Monocline, 12. Muscovite, 26, 34. Neck, volcanic, 20. Nepheline, 34. Norite. Oligoclase, 25. Olivine, 28, 82. INDEX 263 Onyx marbles, 166, 180-181. Oolitic limestones, 157. Ophicalcite, 82, 84. Ophimagnesite, 82, 84. Origin of clays, 218-237. Origin of rock, 8-11. Orthoclase, 25. Output (see production statistics). Paving blocks, 65, 78, 79. Pegmatites, 37. Peridot, 28. Peridotite, 30, 70. Pholerite, 222. Plagioclase, 25. Porosity, 198-202. Porphyry, 30. Pozzuolana, 31. Production, statistics of: granite, 61-67. limestone, 162-165. marble, 174-175, 179-180. sandstone, 144-147. slate, 122-125. soapstone and talc, 88-90. Profits of stone industry, 190-191. Pumice, 21, 31. Puzzolan materials, 31. Pyrite in limestone, 153. Pyrite in serpentine, 85. Pyroxene, 27, 82. Pyroxenite, 29, 70, 224. Quarry examination, 182-184. Quarry finances, 190-191. Quartz, 25-34. Quartzite, 142. Reference lists: building stone, testing, 216-217. clays, distribution, 240-243. clays, examination, 257. clays, origin, 236-237. granites, 68-69. limestone, 160-162. marbles, crystalline, 175-177. marbles, subcrystalline, 180. Reference lists (continued): marbles, onyx, 181. sandstones, 148-149. serpentine, 87. slate, distribution, 125-126. slate, origin, 102. slate, testing, 113. soapstone and talc, 90. trap, 80. Residual clays, 219, 221-230. Rift (in granite), 15, 39. Sand, 10, 127. Sandstone, 127-149, 227. Sedimentary rocks, 6, 91. Serpentine, 31, 81-87. Shale clays, 224-227, 232-233. Sheets (igneous), 19, 20. Sheet structure (in granites), 39. Shells, composition of, 151. Sills (igneous), 20. Sizes of slate, 120-121. Slate, 95-126. Soapstone, 87-90. Sodium-sulphate test, 205-207. Specific gravity, 198-202. acid rocks, 55-60. basic rocks, 75, 85, 86. clays, 258-260. granites, 55-60. limestone, 157, 159. marbles, 172-173. sandstones, 139-142. serpentine, 85, 86. shale, 258-260. slate, 112. trap, 77. Square (of slate), 119. Statistics (see production statistics). Stocks (igneous), 19. Stock issues, 194-195. Stream clays, 233-234. Strength (see compressive strength). Strength (see transverse strength). Strike of rocks, 11. Sulphate of soda test, 205-207. Syenite, 29, 34. Syncline, 12. 264 INDEX Talc, 81, 87-90. Terraces, river, 233-234. Testing methods, stone, 195-217. Thickness of slates, 121. Transported clays, 231-237. Transverse strength, 216. granites, 60. slates, 112. Trap, 30, 31, 70-80. Travertine, 157. Tufa, calcareous, 157. Tuff, 128. Verde antique, 81-87. Volcanic ash, 20, 21, 128. Volcanic products, 19, 21. Volcanoes, 19. Wear, resistance to, 216. Weathering, 188, 221-230, 257-258. Weight per cubic foot, 198-202. clays, 258-260. granites, 55, 60. limestones, 157, 159. marbles, 172, 173. sandstones, 139-142. serpentines, 85, 86. shales, 258-260 trap, 77. Wind-borne clays, 234, 236. SHORT-TITLE CATALOGUE PUBLICATIONS OF JOHN WILEY & SONS NEW YORK LONDON: CHAPMAN & HALL, LIMITED ARRANGED UNDER SUBJECTS Descriptive circulars sent on application. Books marked with an asterisk (*) arc sold at net prices only. All books are bound in cloth unless otherwise stated. AGRICULTURE HORTICULTURE FORESTRY. Armsby's Principles of Animal Nutrition . 8vo, $4 00 * Bowman's Forest Physiography 8vo, 5 00 Budd and Hansen's American Horticultural Manual: Part I. Propagation, Culture, and Improvement 12mo, 1 50 Part II. Systematic Pomology 12mo, 1 50 Elliott's Engineering for Land Drainage 12mo, 2 00 Practical Farm Drainage. (Second Edition, Rewritten.) 12mo, 1 50 Fuller's Water Supplies for the Farm. (In Press.) Graves's Forest Mensuration 8vo, 4 00 * Principles of Handling Woodlands Large 12mo, 1 50 Green's Principles of American Forestry 12mo, 1 50 Grotenfelt's Principles of Modern Dairy Practice. (Woll.) 12mo, 2 00 Hawley and Hawes's Practical Forestry for New England. (In Press.) 'I * Herrick's Denatured or Industrial Alcohol I 8vo, 4 00 * Kemp and Waugh's Landscape Gardening. (New Edition, Rewritten.) 12mo, 1 50 * McKay and Larsen's Principles and Practice of Butter-making 8vo, 1 50 Maynard's Landscape Gardening as Applied to Home Decoration 12mo, 1 50 Record's Identification of the Economic Woods of the United States. (In Press. ) Sanderson's Insects Injurious to Staple Crops 12mo, 1 50 * Insect Pests of Farm, Garden, and Orchard Large 12mo. 3 00 * Schwarz's Longleaf Pine in Virgin Forest 12mo, 1 25 * Solotaroff's Field Book for Street-tree Mapping 12mo, 75 In lots of one dozen 8 00 * Shade Trees in Towns and Cities 8vo, 3 00 Stockbridge's Rocks and Soils 8vo, 2 50 Winton's Microscopy of Vegetable Foods 8vo, 7 50 WoU's Handbook for Farmers and Dairymen 16mo. 1 50 ARCHITECTURE. * Atkinson's Orientation of Buildings or Planning for Sunlight 8vo, 2 00 Baldwin's Steam Heating for Buildings 12mo, 2 50 Berg's Buildings and Structures of American Railroads 4to, 5 00 1 Birkmire's Architectural Iron and Steel 8vo, $3 50 Compound Riveted Girders as Applied in Buildings 8vo,' 2 00 Planning and Construction of High Office Buildings 8vo, 3 50 Skeleton Construction in Buildings 8vc, 3 00 Briggs's Modern American School Buildings * 8vo,' 4 00 Byrne's Inspection of Materials and Workmanship Employed in Construction. 16mo, 3 00 Carpenter's Heating and Ventilating of Buildings 8vo, 4 00 * Corthell's Allowable Pressure on Deep Foundations 12mo, 1 25 * Eckel's Building Stones and Clays 8vo, 3 00 Freitag's Architectural Engineering 8vo, 3 50 Fire Prevention and Fire Protection. (In Press.) Fireproofing of Steel Buildings 8vo, 2 50 Gerhard's Guide to Sanitary Inspections. (Fourth Edition, Entirely Re- vised and Enlarged.) 12mo, 1 50 * Modern Baths and Bath Houses ; 8vo, 3 00 Sanitation of Public Buildings 12mo, 1 50 Theatre Fires and Panics 12mo, 1 50 * The Water Supply, Sewerage and Plumbing of Modern City Buildings, 8vo, 4 00 Johnson's Statics by Algebraic and Graphic Methods 8vo, 2 00 Kellaway's How to Lay Out Suburban Home Grounds 8vo, 2 00 Kidder's Architects' and Builders' Pocket-book 16mo, mor., 5 00 Merrill's Stones for Building and Decoration 8vo, 5 00 Monckton's Stair-building 4to, 4 00 Patton's Practical Treatise on Foundations 8vo, 5 00 Peabody's Naval Architecture 8vc, 7 50 Rice's Concrete-block Manufacture 8vo, 2 00 Richey's Handbook for Superintendents of Construction 16mo, mor. 4 00 Building Foreman's Pocket Book and Ready Reference. . 16mo, mor.. 5 00 * Building Mechanics' Ready Reference Series: * Carpenters' and Woodworkers' Edition 16mo, mor. 1 50 * Cement Workers' and Plasterers' Edition 16mo, mor. * Plumbers', Steam-Fitters', and Tinners' Edition. . . 16mo, mor. * Stone- and Brick-masons' Edition 16mo, mor. Sabin's House Painting 12mo, Siebert and Biggin's Modern Stone-cutting and Masonry 8vo, Snow's Principal Species of Wood 8vo, 3 50 Wait's Engineering and Architectural Jurisprudence 8vo, 6 00 Sheep, 6 50 Law of Contracts 8vo, 3 00 Law of Operations Preliminary to Construction in Engineering and Architecture 8vo, 5 00 Sheep, 5 50 Wilson's Air Conditioning 12mo, 1 50 Worcester and Atkinson's Small Hospitals, Establishment and Maintenance, Suggestions for Hospital Architecture, with Plans for a Small Hospital 12mo, 1 25 ARMY AND NAVY. Bernadou's Smokeless Powder, Nitro-cellulose, and the Theory of the Cellu- lose Molecule 12mo, 2 50 Chase's Art of Pattern Making 12mo, 2 50 Screw Propellers and Marine Propulsion 8vo, 3 00 * Cloke's Enlisted Specialists' Examiner 8vo, 2 00 * Gunner's Examiner 8vo, 1 50 Craig's Azimuth 4tu, 3 50 Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 00 * Davis's Elements of Law 8vo, 2 50 * Treatise on the Military Law of United States 8vo. 7 00 * Dudley's Military Law and the Procedure of Courts-martial. . .Large 12mo, 2 50 Durand's Resistance and Propulsion of Ships 8vc. 5 00 * Dyer's Handbook of Light Artillery 12mo, 3 00 2 ' Eissler's Modern High Explosives 8vo $4 00 * Fiebeger's Text-book on Field Fortification Large 12mo, 2 00 Hamilton and Bond's The Gunner's Catechism 18mo, 1 00 * Hoff 's Elementary Naval Tactics 8vo, 1 50 Ingalls's Handbook of Problems in Direct Fire 8vo, 4 00 * Interior Ballistics 8vo. 3 00 * Lissak's Ordnance and Gunnery 8vo, 6 00 * Ludlow's Logarithmic and Trigonometric Tables 8vo, 1 00 * Lyons's Treatise on Electromagnetic Phenomena. Vols. I. and II..8vo,each, 6 00 * Mahan's Permanent Fortifications. (Mercur.) 8vo, half mor. 7 50 Manual for Courts-martial 16mo, mor. 1 50 * Mercur's Attack of Fortified Places 12mo, 2 00 * Elements of the Art of War 8vo, 4 00 Nixon's Adjutants' Manual 24mo, 1 00 Peabody's Naval Architecture 8vo, 7 50 * Phelps's Practical Marine Surveying 8vo, 2 50 Putnam's Nautical Charts 8vo, 2 00 Rust's Ex-meridian Altitude, Azimuth and Star- Finding Tables 8vo, 5 00 * Selkirk's Catechism of Manual of Guard Duty 24mo, 50 Sharpe's Art of Subsisting Armies in War 18mo, mor. 1 50 * Taylor's Speed and Power of Ships. 2 vols. Text 8vo, plates oblong 4to, 7 50 * Tupes and Poole's Manual of Bayonet Exercises and Musketry Fencing. 24mo, leather, 50 * Weaver's Military Explosives 8vo, 3 00 * Woodhull's Military Hygiene for Officers of the Line Large 12mo, 1 50 ASSAYING. Betts's Lead Refining by Electrolysis 8vo, 4 00 *Butler's Handbook of Blowpipe Analysis 16mo, 75 Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe. 16mo, mor. 1 50 Furman and Pardoe's Manual of Practical Assaying 8vo, 3 00 Lodge's Notes on Assaying and Metallurgical Laboratory Experiments.. 8vb, 3 00 Low's Technical Methods of Ore Analysis 8vo, 3 00 Miller's Cyanide Process 12mo, 1 00 Manual of Assaying 12mo, 1 00 Minet's Production of Aluminum and its Industrial Use. (Waldo.). ..12m& 2 50 Ricketts and Miller's Notes on Assaying 8vc 3 00 Robine and Lenglen's Cyanide Industry. (Le Clerc.) 8vc, 4 00 * Seamon's Manual for Assayers and Chemists Large 12mo, 2 50 Ulke's Modern Electrolytic Copper Refining 8vo, 3 00 Wilson's Chlorination Process 12mo, 1 50 Cyanide Processes 12mo, 1 50 ASTRONOMY. Comstock's Field Astronomy for Engineers 8vo, 2 50 Craig's Azimuth 4to, 3 50 Crandall's Text-book on Geodesy and Least Squares 8vo, 3 00 Doolittle's Treatise on Practical Astronomy 8vo, 4 00 Hayford's Text-book of Geodetic Astronomy 8vo, 3 00 Hosmer's Azimuth 16mo, mor. 1 00 * Text-book on Practical Astronomy 8vo, 2 00 Merriman's Elements of Precise Surveying and Geodesy u . .8vo, 2 50 * Michie and Harlow's Practical Astronomy 8vo, 3 00 Rust's Ex-meridian Altitude, Azimuth and Star-Finding Tables 8vo, 5 00 * White's Elements of Theoretical and Descriptive Astronorry 12mo, 2 00 CHEMISTRY. * Abderhalden's Physiological Chemistry in Thirty Lectures. (Hall and Defren.) 8vo, 5 00 * Abegg's Theory of Electrolytic Dissociation, (von Ende.) 12mo, 1 25 Alexeyeff's General Principles of Organic Syntheses. (Matthews.) 8vo, 3 00 3 Allen's Tables for Iron Analysis 8vo, $3 00 Armsby 's Principles of Animal Nutrition 8vo, 4 00 Arnold's Compendium of Chemistry. (Mandel.) Large 12mo, 3 50 Association of State and National Food and Dairy Departments, Hartford Meeting, 1906 8vo, 3 00 . Jamestown Meeting, 1907 8vo, 3 00 Austen's Notes for Chemical Stuasnts 12mo, 1 50 Bernadou's Smokeless Powder. Nitro-cellulose, and Theory of the Cellulose Molecule 12mo, 2 50 * Biltz's Introduction to Inorganic Chemistry. (Hall and Phelan.). . . 12mo, 1 25 Laboratory Methods of Inorganic Chemistry. (Hall and Blanchard.) 8vo, 3 00 * Bingham and White's Laboratory Manual of Inorganic Chemistry. ,12mo. 1 00 * Blanchard 's Synthetic Inorganic Chemistry 12mo, 1 00 * Bottler's German and American Varnish Making. (Sabin.) . .Large 12mo, 3 50 Browne's Handbook of Sugar Analysis. (In Press.) * Browning's Introduction to the Rarer Elements 8vo, 1 50 * Butler's Handbook of Blowpipe Analysis 16mo, 75 * Claassen's Beet-sugar Manufacture. (Hall and Rolfe.) 8vo, 3 00 Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.).8vo, 3 00 Cohn's Indicators and Test-papers 12mo, 2 00 Tests and Reagents 8vo, 3 00 Cohnheim's Functions of Enzymes and Ferments. (In Press.) * Danneel's Electrochemistry. (Merriam.) 12mo, 1 25 Dannerth's Methods of Textile Chemistry 12mo, 2 00 Duhem's Thermodynamics and Chemistry. (Burgess.) 8vo, 4 00 Effront's Enzymes and their Applications. (Prescott.) 8vo, 3 00 Eissler's Modern High Explosives 8vo. 4 00 * Fischer's Oedema 8vo, 2 00 * Physiology of Alimentation Large 12mo, 2 00 Fletcher's Practical Instructions in Quantitative Assaying with the Blowpipe. 16mo, mor. 1 50 Fowler's Sewage Works Analyses 12mo, 2 00 Fresenius's Manual of Qualitative Chemical Analysis. (Wells.) 8vo, 5 00 Manual of Qualitative Chemical Analysis. Part I. Descriptive. (Wells.)8vo, 3 00 Quantitative Chemical Analysis. (Cohn.) 2 vols 8vc, 12 50 When Sold Separately, Vol. I, $6. Vol. II, $8. Fuertes's Water and Public Health 12mo, 1 50 ?urman and Pardoe's Manual of Practical Assaying 8vo, 3 00 * Getman's Exercises in Physical Chemistry 12mo, 2 00 Gill's Gas and Fuel Analysis for Engineers 12mo, 1 25 Gooch's Summary of Methods in Chemical Analysis. (In Press.) * Gooch and Browning's Outlines of Qualitative Chemical Analysis. Large 12mo, 1 25 Grotenfelt's Principles of Modern Dairy Practice. (Woll.) 12mo, 2 00 Groth's Introduction to Chemical Crystallography (Marshall) 12mo, 1 25 * Hammarsten's Text-book of Physiological Chemistry. (Mandel.) 8vo, 4 00 Hanausek's Microscopy of Technical Products. (Winton.) 8vo, 5 00 * Haskins and Macleod's Organic Chemistry 12mo, 2 00 * Herrick's Denatured or Industrial Alcohol 8vo, 4 00 Hinds's Inorganic Chemistry 8vo, 3 00 * Laboratory Manual for Students 12mo, 1 00 * Holleman's Laboratory Manual of Organic Chemistry for Beginners. (Walker.) 12mo, 1 00 Text-book of Inorganic Chemistry. (Cooper.) 8vo, 2 50 Text-book of Organic Chemistry. (Walker and Mott.) 8vo, 2 50 Holley's Analysis of Paint and Varnish Products. (In Press.) * Lead and Zinc Pigments Large 12mo, 3 00 Hopkins's Oil-chemists' Handbook 8vo 3 00 Jackson's Directions for Laboratory Work in Physiological Chemistry. .8vo, 1 25 Johnson's Rapid Methods for the Chemical Analysis of Special Steels, Steel- making Alloys and Graphite Large 12mo, 3 00 Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 00 Lassar-Cohn's Application of Some General Reactions to Investigations in Organic Chemistry. (Tingle.) 12mo, 1 00 Leach's Inspection and Analysis of Food with Special Reference to State Control 8vo, 7 50 Lob's Electrochemistry of Organic Compounds. (Lorenz.) 8vo, $3 00 Lodge's Notes on Assaying and Metallurgical Laboratory Experiments.. 8vo, 3 00 Low's Technical Method of Ore Analysis 8vo, 3 00 Lowe's Paint for Steel Structures 12mo, 1 00 Lunge's Techno-chemical Analysis. (Cohn.) 12mo, 1 00 * McKay and Larsen's Principles and Practice of Butter-making 8vo, 1 50 Maire's Modern Pigments and their Vehicles 12mo, 2 00 Mandel's Handbook for Bio-chemical Laboratory 12mo, 1 50 * Martin's Laboratory Guide to Qualitative Analysis with the Blowpipe 12mo, 60 Mason's Examination of Water. (Chemical and Bacteriological.) 12mo, 1 25 Water-supply. (Considered Principally from a Sanitary Standpoint.) 8vo, 4 00 * Mathewson's First Principles of Chemical Theory 8vo, 1 00 Matthews's Laboratory Manual of Dyeing and Textile Chemistry 8vo, 3 50 Textile Fibres. 2d Edition, Rewritten 8vo, 4 00 * Meyer's Determination of Radicles in Carbon Compounds. (Tingle.) Third Edition 12mo, 1 25 Miller's Cyanide Process 12mo, 1 00 Manual of Assaying 12mo, 1 00 Minet's Production of Aluminum and its Industrial Use. (Waldo.). ..12mo, 2 50> * Mittelstaedt's Technical Calculations for Sugar Works. (Bourbakis.) 12mo, 1 5O Mixter's Elementary Text-book of Chemistry 12mo, 1 50 Morgan's Elements of Physical Chemistry 12mo, 3 00 * Physical Chemistry for Electrical Engineers 12mo, 1 50 * Moore's Experiments in Organic Chemistry 12mo, 50 * Outlines of Organic Chemistry 12mo, 1 50 Morse's Calculations used in Cane-sugar Factories 16mo, mor. 1 50 * Muir's History of Chemical Theories and Laws , 8vo, 4 OQ Mulliken's General Method for the Identification of Pure Organic Compounds. Vol. I. Compounds of Carbon with Hydrogen 'and Oxygen. Large 8vo, 5 00 Vol. II. Nitrogenous Compounds. (In Preparation.) Vol. III. The Commercial Dyestuffs Large 8vo, 5 00 * Nelson's Analysis of Drugs and Medicines 12mo, 5 00 Ostwald's Conversations on Chemistry. Part One. (Ramsey.) 12mo, 1 50 Part Two. (Turnbull.) 12mo, 2 00 * Introduction to Chemistry. (Hall and Williams.) Large 12mo, 1 50 Owen and Standage's Dyeing and Cleaning of Textile Fabrics 12mo, 2 00 * Palmer's Practical Test Book of Chemistry 12mo, 1 00 * Pauli's Physical Chemistry in the Service of Medicine. (Fischer.) .. 12mo, 1 25 Penfield's Tables of Minerals, Including the Use of Minerals and Statistics of Domestic Production 8vo, 1 00 Pictet's Alkaloids and their Chemical Constitution. (Biddle.). 8vo, 5 00 Poole's Calorific Power of Fuels 8vo, 3 00 Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- ence to Sanitary Water Analysis 12mo, 1 50 * Reisig's Guide to Piece-Dyeing 8vo, 25 00 Richards and Woodman's Air, Water, and Food from a Sanitary Stand- point 8vo. 2 00 Ricketts and Miller's Notes on Assaying 8vo, 3 00 Rideal's Disinfection and the Preservation of Food 8vo, 4 00 Riggs's Elementary Manual for the Chemical Laboratory 8vo, 1 25 Robine and Lenglen's Cyanide Industry. (Le Clerc.) ; . . . .8vo, 4 00 Ruddiman's Incompatibilities in Prescriptions 8vo, 2 00 Whys in Pharmacy 12mo, 1 00 * Ruer's Elements of Metallography. (Mathewson.) 8vo, 3 00 Sabin's Industrial and Artistic Technology of Paint and Varnish 8vo, 3 00 Salkowski's Physiological and Pathological Chemistry. (Orndorff.) 8vo, 2 50 * Schimpf's Essentials of Volumetric Analysis Large 12mo, 1 50 Manual of Volumetric Analysis. (Fifth Edition, Rewritten) 8vo, 5 00 * Qualitative Chemical Analysis 8vo, 1 25 * Seamon's Manual for Assayers and Chemists. . . Large 12mo, 2 50 Smith's Lecture Notes on Chemistry for Dental Students 8vo, 2 50/ Spencer's Handbook for Cane Sugar Manufacturers . 16mo, mor. 3 00 Handbook for Chemists of Beet-sugar Houses 16mo, mor. 3 00 Stockbridge's Rocks and Soils 8vo, 2 50 Stone's Practical Testing of Gas and Gas Meters 8vo, 3 5O 5 * Tillman's Descriptive General Chemistry 8vo, $3 00 * Elementary Lessons in Heat 8vo, 1 50 Treadwell's Qualitative Analysis. (Hall.) 8vo, 3 00 Quantitative Analysis, (Hall.) 8vo, 4 00 Turneaure and Russell's Public Water-supples 8vo, 5 00 Van Deventer's Physical Chemistry for Beginners. (Boltwood.) 12mo, 1 50 Venable's Methods and Devices for Bacterial Treatment of Sewage 8vo, 3 00 Ward and Whipple's Freshwater Biology. (In Press.) Ware's Beet-sugar Manufacture and Refining. Vol. 1 8vo, 4 00 Vol. II 8vo, 5 00 Washington's Manual of the Chemical Analysis of Rocks 8vo, 2 00 * Weaver's Military Explosives 8vo, 3 00 Wells's Laboratory Guide in Qualitative Chemical Analysis 8vo, 1 50 Short Course in Inorganic Qualitative Chemical Analysis for Engineering Students 12mo, 1 50 Text-book of Chemical Arithmetic 12mo, 1 25 Whipple's Microscopy of Drinking-water 8vo, 3 50 Wilson's Chlorination Process 12mo, 1 50 Cyanide Processes 12mo, 1 50 Winton's Microscopy of Vegetable Foods 8vo, 7 50 Zsigmondy's Colloids and the Ultramicroscope. ( Alexander.).. Large 12mo, 3 00 CIVIL ENGINEERING. BRIDGES AND ROOFS. HYDRAULICS. MATERIALS OF ENGINEER- ING. RAILWAY ENGINEERING. * American Civil Engineers' Pocket Book. (Mansfield Merriman, Editor- in-chief.) 16mo. mor. 5 00 Baker's Engineers' Surveying Instruments 12mo, 3 00 Bixby's Graphical Computing Table '. Paper 19i X 24 J inches. 25 Breed and Hosmer's Principles and Practice of Surveying. Vol. I. Elemen- tary Surveying 8vo, 3 00 Vol. II. Higher Surveying 8vo, 2 50 * Burr's Ancient and Modern Engineering and the Isthmian Canal 8vo, 3 50 Comstock's Field Astronomy for Engineers 8vo, 2 50 * CortheH's Allowable Pressure on Deep Foundations 12mo, 1 25 Crandall's Text-book on Geodesy and Least Squares 8vo, 3 00 Davis's Elevation and Stadia Tables 8vo, 1 00 * Eckel's Building Stones and Clays 8vo, 3 00 Elliott's Engineering for Land Drainage 12mo, 2 00 * Fiebeger's Treatise on Civil Engineering 8vo, 5 00 Flemer's Phototopographic Methods and Instruments 8vo, 5 00 Folwell's Sewerage. (Designing and Maintenance.) 8vo, 3 00 Freitag's Architectural Engineering 8vo, 3 50 French and Ives's Stereotomy 8vo, 2 50 Gilbert, Wightman, and Saunders's Subways and Tunnels of New York. (In Press.) * Hauch and Rice's Tables of Quantities for Preliminary Estimates. . . 12mo, 1 25 Hayford's Text-book of Geodetic Astronomy 8vo, 3 00 Bering's Ready Reference Tables (Conversion Factors.) 16mo, mor. 2 50 Hosmer's Azimuth 16mo, mor. 1 00 * Text-book on Practical Astronomy 8vo, 2 00 Howe's Retaining Walls for Earth 12mo, 1 25 * Ives's Adjustments of the Engineer's Transit and Level 16mo, bds. 25 Ives and Hilts's Problems in Surveying, Railroad Surveying and Geod- esy 16mo, mor. 1 50 * Johnson (J.B.) and Smith's Theory and Practice of Surveying . Large 12mo, 3 50 Johnson's (L. J.) Statics by Algebraic and Graphic Methods 8vo, 2 00 * Kinnicutt, Winslow and Pratt's Sewage Disposal 8vo, 3 00 * Mahan's Descriptive Geometry 8vo, 1 50 Merriman's Elements of Precise Surveying and Geodesy 8vo, 2 50 Merriman and Brooks's Handbook for Surveyors 16mo, mor. 2 00 Nugent's Plane Surveying 8vo, 3 50 Ogden's Sewer Construction 8vo, 3 00 Sewer Design 12mo, 2 00 6 Ogden and Cleveland's Practical Methods of Sewage Disposal for Resi- dences, Hotels, and Institutions. (In Press.) Parsons's Disposal of Municipal Refuse 8vo, $2 00 Patton's Treatise on Civil Engineering 8vo, half leather, 7 60 Reed's Topographical Drawing and Sketching 4to, 5 00 Riemer's Shaft-sinking under Difficult Conditions. (Corning and Peele.).8vo. 3 00 Siebert and Biggin's Modern Stone-cutting and Masonry 8vo, 1 50 Smith's Manual of Topographical Drawing. (McMillan.) 8vo, 2 50 Soper's Air and Ventilation of Subways 12mo, 2 50 * Tracy's Exercises in Surveying 12mo, mor. 1 00 Tracy's Plane Surveying . 16mo, mor. 3 00 Venable's Garbage Crematories in America 8vo, 2 00 Methods and Devices for Bacterial Treatment of Sewage 8vo, 3 00 Wait's Engineering and Architectural Jurisprudence 8vo, 6 00 Sheep, 6 50 Law of Contracts 8vo, 3 00 Law of Operations Preliminary to Construction in Engineering and Architecture 8vo, 5 00 Sheep, 5 50 Warren's Stereotomy Problems in Stone-cutting, 8vo, 2 50 * Waterbury's Vest-Pocket Hand-book of Mathematics for Engineers. 2$X5f inches, mor. 1 00 * Enlarged Edition, Including Tables mor. 1 50 Webb's Problems in the Use and Adjustment of Engineering Instruments. 16mo, mor. 1 25 Wilson's Topographic Surveying 8vo, 3 50 BRIDGES AND ROOFS. Boiler's Practical Treatise on the Construction of Iron Highway Bridges.. 8vo, 2 00 * Thames River Bridge Oblong paper, 5 00 Burr and Falk's Design and Construction of Metallic Bridges 8vo, 5 00 Influence Lines for Bridge and Roof Computations 8vo, 3 00 Du Bois's Mechanics of Engineering. Vol. II Small 4to, 10 00 Foster's Treatise on Wooden Trestle Bridges 4to, 5 00 Fowler's Ordinary Foundations 8vo, 3 50 Greene's Arches in Wood, Iron, and Stone 8vo, 2 50 Bridge Trusses 8vo, 2 50 Roof Trusses 8vo, 1 25 Grimm's Secondary Stresses in Bridge Trusses 8vo, 2 50 Heller's Stresses in Structures and the Accompanying Deformations 8vo, 3 00 Howe's Design of Simple Roof-trusses in Wood and Steel 8vo. 2 00 Symmetrical Masonry Arches 8vo, 2 50 Treatise on Arches. .' 8vo, 4 00 * Hudson's Deflections and Statically Indeterminate Stresses Small 4to, 3 50 * Plate Girder Design 8vo, 1 50 * Jacoby's Structural Details, or Elements of Design in Heavy Framing, 8vo, 2 25 Johnson, Bryan and Turneaure's Theory and Practice in the Designing of > Modern Framed Structures Small 4to, 10 00 *^Johnson, Bryan and Turneaure's Theory and Practice in the Designing of Modern Framed Structures. New Edition. Part I. 8vo, 3 00 * Part II. New Edition 8vo, 4 00 Merriman and Jacoby's Text-book on Roofs and Bridges: Part I. Stresses in Simple Trusses 8vo v 2 50 Part II. Graphic Statics 8vo, 2 50 Part III. Bridge Design 8vo, 2 50 Part IV. Higher Structures 8vo, 2 50 Ricker's Design and Construction of Roofs. (In Press.) Sondericker's Graphic Statics, with Applications to Trusses, Beams, and Arches 8vo, 2 00 Waddell's De Pontibus, Pocket-book for Bridge Engineers 16mo, mor. 2 00 * Specifications for Steel Bridges 12mo, 50 Waddell and Harrington's Bridge Engineering. (In Preparation.) HYDRAULICS. Barnes's Ice Formation 8vo, 3 00 Bazin's Experiments upon the Contraction of the Liquid Vein Issuing from an Orifice. (Trautwine.) 8vo, 2 00 7 Bovey's Treatise on Hydraulics 8vo, $5 00 Church's Diagrams of Mean Velocity of Water in Open Channels. Oblong 4to, paper, 1 50 Hydraulic Motors . 8vo, 2 00 Mechanics of Fluids (Being Part IV of Mechanics of Engineering) . . 8vo, 3 00 Coffin's Graphical Solution of Hydraulic Problems 16mo, mor. 2 50 Flather's Dynamometers, and the Measurement of Power 12mo, 3 00 Folwell's Water-supply Engineering 8vo, 4 00 Frizell's Water-power 8vo, 5 00 Fuertes's Water and Public Health 12mo, 1 50 Water-filtration Works 12mo, 2 50 Ganguillet and Kutter's General Formula for the Uniform Flow of Water in Rivers and Other Channels. (Hering and Trautwine.) 8vo, 4 00 Hazen's Clean Water and How to Get It Large 12mo, 1 50 Filtration of Public Water-supplies 8vo, 3 00 Hazelhurst's Towers and Tanks for Water-works 8vo, 2 50 Herschel's 115 Experiments on the Carrying Capacity of Large, Riveted, Metal Conduits 8vo, 2 00 Hoyt and Grover's River Discharge 8vo, 2 00 Hubbard and Kiersted's Water-works Management and Maintenance. 8vo, 4 00 * Lyndon's Development and Electrical Distribution of Water Power. 8vo, 3 00 Mason's Water-supply. (Considered Principally from a Sanitary Stand- point.) 8vo, 4 00 * Merriman's Treatise on Hydraulics. 9th Edition, Rewritten 8vo, 4 00 * Molitor's Hydraulics of Rivers, Weirs and Sluices 8vo, 2 00 * Morrison and Brodie's High Masonry Dam Design 8vo, 1 50 * Richards's Laboratory Notes on Industrial Water Analysis 8vo, 50 Schuyler's Reservoirs for Irrigation, Water-power, and Domestic Water- supply. Second Edition, Revised and Enlarged Large 8vo, 6 00 * Thomas and Watt's Improvement of Rivers 4to, 6 00 Turneaure and Russell's Public Water-supplies 8vo, 5 00 * Wegmann's Design and Construction of Dams. 6th Ed., enlarged 4to, 6 00 Water-Supply of the City of New York from 1658 to 1895 4to, 10 00 Whipple's Value of Pure Water Large 12mo, 1 00 Williams and Hazen's Hydraulic Tables 8vo, 1 50 Wilson's Irrigation Engineering 8vo, 4 00 Wood's Turbines. .. . . .8vo, 250 MATERIALS OF ENGINEERING. Baker's Roads and Pavements 8vo, 5 00 Treatise on Masonry Construction 8vo, 5 00 Black's United States Public Works Oblong 4to, 5 00 * Blanchard and Drowne's Highway Engineering, as Presented at the Second International Road Congress, Brussels, 1910 8vo, 2 00 Bleininger's Manufacture of Hydraulic Cement. (In Preparation.) * Bottler's German and American Varnish Making. (Sabin.) . .Large 12mo. 3 50 Burr's Elasticity and Resistance of the Materials of Engineering 8vo, 7 50 Byrne's Highway Construction 8vo, 5 00 Inspection of the Materials and Workmanship Employed in Construction. 16mo, 3 00 Church's Mechanics of Engineering 8vo, 6 00 Mechanics of Solids (Being Parts I, II, III of Mechanics of Engineer- ing 8vo, 4 50 Du Bois's Mechanics of Engineering. Vol. I. Kinematics, Statics, Kinetics -. Small 4to, 7 50 Vol. II. The Stresses in Framed Structures, Strength of Materials and Theory of Flexures Small 4to, 10 00 * Eckel's Building Stones and Clays 8vo. 3 00 * Cements, Limes, and Plasters 8vo, 6 00 Fowler's Ordinary Foundations 8vo, 3 50 * Greene's Structural Mechanics 8vo, 2 50 Holley's Analysis of Paint and Varnish Products. (In Press.) * Lead and Zinc Pigments Large 12mo, 3 00 8 * Hubbard's Dust Preventives and Road Binders 8vo, $3 00 Johnson's (C. M.) Rapid Methods for the Chemical Analysis of Special Steels, Steel-making Alloys and Graphite Large 12mo, 3 00 Johnson's (J. B.) Materials of Construction Large 8vo, 6 00 Keep's Cast Iron 8vo, 2 50 Lanza's Applied Mechanics 8vo, 7 50 Lowe's Paints for Steel Structures 12mo, 1 00 Maire's Modern Pigments and their Vehicles 12mo, 2 00 * Martin's Text Book on Mechanics. Vol. I. Statics 12mo, 1 25 * Vol. II. Kinematics and Kinetics 12mo, 1 50 * Vol. III. Mechanics of Materials 12mo, 1 50 Maurer's Technical Mechanics 8vo, 4 00 Merrill's Stones for Building and Decoration 8vo, 5 00 Merriman's Mechanics of Materials 8vo, 5 00 * Strength of Materials 12mo, 1 00 Metcalf 's Steel. A Manual for Steel-users 12mo, 2 00 Morrison's Highway Engineering 8vo, 2 50 * Murdock's Strength of Materials ....... 12mo, 2 00 Patton's Practical Treatise on Foundations 8vo, 5 00 Rice's Concrete Block Manufacture 8vo, 2 00 Richardson's Modern Asphalt Pavement 8vo, 3 00 Richey's Building Foreman's Pocket Book and Ready Reference. 16mo, mor. 5 00 * Cement Workers' and Plasterers' Edition (Building Mechanics' Ready Reference Series) 16mo, mo: . 1 50 Handbook for Superintendents of Construction 16mo, mor. 4 00 * Stone and Brick Masons' Edition (Building Mechanics' Ready Reference Series) 16mo, mor. 1 50 * Ries's Clays : Their Occurrence, Properties, and Uses 8vo, 5 00 * Ries and Leighton's Histofl^ of the Clay-working Industry of, the United States 8vo. 2 50 Sabin's Industrial and Artistic Technology of Paint and Varnish 8vo, 3 00 * Smith's Strength of Material 12mo, 1 25 Snow's Principal Species of Wood 8vo, 3 50 Spalding's Hydraulic Cement 12mo. 2 00 Text-book on Roads and Pavements 12mo, 2 00 * Taylor and Thompson's Concrete Costs Small 8vo, 5 00 * Extracts on Reinforced Concrete Design 8vo, 2 00 Treatise on Concrete, Plain and Reinforced 8vo, 5 00 Thurston's Materials of Engineering. In Three Parts 8vo, 8 00 Part I. Non-metallic Materials of Engineering and Metallurgy.. . .8vo, 2 00 Part II. Iron and Steel 8vo, 3 50 Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their Constituents 8vo, 2 50 Tillson's Street Pavements and Paving Materials 8vo, 4 00 Turneaure and Maurer's Principles of Reinforced Concrete Construction. ( Second Edition, Revised and Enlarged 8vo, 3 50 Waterbu'ry's Cement Laboratory Manual 12mo, 1 00 * Laboratory Manual for Testing Materials of Construction 12mo, 1 50 Wood's (De V.) Treatise on the Resistance of Materials, and an Appendix on the Preservation of Timber 8vo, 2 00 Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and Steel 8vo, 4 00 RAILWAY ENGINEERING. Andrews's Handbook for Street Railway Engineers 3X5 inches, mor. 1 25 Berg's Buildings and Structures of American Railroads 4to, 5 00 Brooks's Handbook of Street Railroad Location 16mo, mor. 1 50 * Burt's Railway Station Service 12mo, 2 00 Butts's Civil Engineer's Field-book 16mo, mor. 2 50 Crandall's Railway and Other Earthwork Tables 8vo, 1 50 Crandall and Barnes's Railroad Surveying 16mo, mor. 2 00 * Crockett's Methods for Earthwork Computations 8vo, 1 50 Dredge's History of the Pennsylvania Railroad. (1879) Paper, 5 00 Fisher's Table of Cubic Yards Cardboard, 25 Godwin's Railroad Engineers' Field-book and Explorers' Guide. . 16mo, mor. 2 50 9 Hudson's Tables for Calculating the Cubic Contents oi Excavations and Em- bankments 8vo, $1 00 Ives and Hilts's Problems in Surveying, Railroad Surveying and Geodesy 16mo, mor. 1 50 Molitor and Beard's Manual for Resident Engineers 16mo, 1 00 Nagle's Field Manual for Railroad Engineers .... 16mo, mor. 3 00 * Orrock's Railroad Structures and Estimates 8vo, 3 00 Philbrick's Field Manual for Engineers 16mo, mor. 3 00 Raymond's Railroad Field Geometry 16mo, mor. 2 00 Elements of Railroad Engineering 8vo, 3 50 Railroad Engineer's Field Book. (In Preparation.) Roberts' Track Formulae and Tables 16mo, mor. 3 00 Searles's Field Engineering 16mo, mor. 3 00 Railroad Spiral 16mo, mor. 1 50 Taylor's Prismoidal Formulae and Earthwork 8vo, 1 50 Webb's Economics of Railroad Construction Large 12mo, 2 50 Railroad Construction 16mo, mor. 5 00 Wellington's Economic Theory of the Location of Railways Large 12mo, 5 00 Wilson's Elements of Railroad-Track and Construction 12mo, 2 00 DRAWING Barr and Wood's .Kinematics of Machinery 8vo, 2 50 * Bartlett's Mechanical Drawing 8vo, 3 00 * " Abridged Ed 8vo, 150 * Bartlett and Johnson's Engineering Descriptive Geometry. 8vo, 1 50 Blessing and Darling's Descriptive Geometry. (In Press.) Elements of Drawing. (In Press.) Coolidge's Manual of Drawing 8vo, paper, 1 00 Coolidge and Freeman's Elements of General Drafting for Mechanical Engi- neers Oblong 4to, 2 50 Durley's Kinematics of Machines 8vo, 4 00 Emch's Introduction to Projective Geometry and its Application 8vo, 2 50 Hill's Text-book on Shades and Shadows, and Perspective 8vo, 2 00 Jamison's Advanced Mechanical Drawing 8vo, 2 00 Elements of Mechanical Drawing 8vo, 2 50 Jones's Machine Design: Part I. Kinematics of Machinery 8vo, 1 50 Part II. Form, Strength, and Proportions of Parts 8vo, 3 00 * Kimball and Barr 's Machine Design 8vo, 3 00 MacCord's Elements of Descriptive Geometry 8vo, 3 00 Kinematics; or, Practical Mechanism 8vo, 5 00 Mechanical Drawing 4to, 4 00 Velocity Diagrams 8vo, 1 50 McLeod's Descriptive Geometry Large 12mo, 1 50 * Mahan's Descriptive Geometry and Stone-cutting 8vo, 1 50 Industrial Drawing. (Thompson.) 8*vo, 3 50 Moyer's Descriptive Geometry 8vo, 2 00 Reed's Topographical Drawing and Sketching 4to, 5 00 * Reid's Mechanical Drawing. (Elementary and Advanced.) 8vo, 2 00 Text-book of Mechanical Drawing and Elementary Machine Design. .8vo, 3 00 Robinson's Principles of Mechanism w 8vo, 3 00 Schwamb and Merrill's Elements of Mechanism 8vo, 3 00 Smith (A. W.) and Marx's Machine Design a 8vo, 3 00 Smith's (R. S.) Manual of Topographical Drawing. (McMillan.) 8vo, 2 50 * Titsworth's Elements of Mechanical Drawing Oblong 8vo, 1 25 Tracy and North's Descriptive Geometry. (In Press.) Warren's Elements of Descriptive Geometry, Shadows, and Perspective. . 8vo, 3 50 Elements of Machine Construction and Drawing 8vo, 7 50 Elements of Plane and Solid Free-hand Geometrical Drawing. . . . 12mo, 1 00 General Problems of Shades and Shadows 8vo, 3 00 Manual of Elementary Problems in the Linear Perspective of Forms and Shadow 12mo, 1 00 Manual of Elementary Projection Drawing 12mo, 1 50 Plane Problems in Elementary Geometry 12mo, 1 25 Weisbach's Kinematics and Power of Transmission. (Hermann and Klein.) 8vo, 5 00 10 Wilson's (H. M.) Topographic Surveying 8vo, $3 50 * Wilson's (V. T.) Descriptive Geometry 8vo, 1 50 Free-hand Lettering 8vo, 1 00 Free-hand Perspective 8vo, 2 50 Woolf's Elementary Course in Descriptive Geometry Large 8vo, 3 00 ELECTRICITY AND PHYSICS. * Abegg's Theory of Electrolytic Dissociation, (von Ende.) 12mo, 1 25 Andrews's Hand-book for Street Railwa y Engineers 3X5 inches mor. 1 25 Anthony and Ball's Lecture-notes on the Theory of Electrical Measure- ments 12mo, 1 00 Anthony and Brackett's Text-book of Physics. (Magie.) ... .Large 12mo, 3 00 Benjamin's History of Electricity 8vo, 3 00 Betts's Lead Refining and Electrolysis 8vo, 4 00 * Burgess and Le Chatelier's Measurement of High Temperatures. Third Edition 8vo, 4 00 Classen's Quantitative Chemical Analysis by Electrolysis. (Boltwood.).Svo, 3 00 * Collins's Manual of Wireless Telegraphy and Telephony 12mo, 1 50 Crehore and Squier's Polarizing Photo-chronograph 8vo, 3 00 * Danneel's Electrochemistry. (Merriam.) 12mo, 1 25 Dawson's "Engineering" and Electric Traction Pocket-book. . . . 16mo, mor. 5 00 Dolezalek's Theory of the Lead Accumulator (Storage Battery), (von Ende.) 12mo, 2 50 Duhem's Thermodynamics and Chemistry. (Burgess.) 8vo, 4 00 Flather's Dynamometers, and the Measurement of Power 12mo, 3 00 * Getman's Introduction to Physical Science 12mo, 1 50 Gilbert's De Magnete. (Mottelay ) 8vo, 2 50 * Hanchett's Alternating Currents 12mo, 1 00 Hering's Ready Reference Tables (Conversion Factors) . . . 16mo, mor. 2 50 * Hobart and Ellis's High-speed Dynamo Electric Machinery 8vo, 6 00 Holman's Precision of Measurements 8vo, 2 00 Telescope-Mirror-scale Method, Adjustments, and Tests Large 8vo, 75 * Hutchinson's High-Efficiency Electrical Illuminants and Illumination. Large 12mo, 2 50 * Jones's Electric Ignition 8vo, 4 00 Karapetoff's Experimental Electrical Engineering: * Vol. 1 8vo, 3 50 * Vol. II 8vo, 2 50 Kinzbrunner's Testing of Continuous-current Machines 8vo, 2 00 Landauer's Spectrum Analysis. (Tingle.) 8vo, 3 00 Lob's Electrochemistry of Organic Compounds. (Lorenz.) 8vo, 3 00 * Lyndon's Development and Electrical Distribution of Water Power. .8vo, 3 00 * Lyons's Treatise on Electromagnetic Phenomena. Vols, I. and II. 8vo, each, 6 00 * Michie's Elements of Wave Motion Relating to Sound and Light 8vo, 4 00 * Morgan's Physical Chemistry for Electrical Engineers 12mo, 1 50 * Norris's Introduction to the Study of Electrical Engineering 8vo, 2 50 Norris and Dennison's Course of Problems on the Electrical Characteristics of Circuits and Machines. (In Press.) * Parshall and Hobart's Electric Machine Design 4to, half mor, 12 50 Reagan's Locomotives: Simple, Compound, and Electric. New Edition. Large 12mo, 3 50 * Rosenberg's Electrical Engineering. ' (Haldane Gee Kinzbrunner.) . .8vo, 2 00 * Ryan's Design of Electrical Machinery: * Vol. I. Direct Current Dynamos 8vo, 1 50 Vol. II. Alternating Current Transformers. (In Press.) Vol. III. Alternators, Synchronous Motors, and Rotary Converters. (In Preparation.) Ryan, Norris, and Hoxie's Text Book of Electrical Machinery 8vo, 2 50 Schapper's Laboratory Guide for Students in Physical Chemistry 12mo, 1 00 * Tillman's Elementary Lessons in Heat 8vo, 1 50 * Timbie's Elements of Electricity Large 12mo, 2 00 * Answers to Problems in Elements of Electricity 12mo, Paper 25 Tory and Pitcher's Manual of Laboratory Physics Large 12mo, 2 00 Ulke's Modern Electrolytic Copper Refining 8vo, 3 00 * Waters's Commercial Dynamo Design 8vo, 2 00 11 LAW. * Brennan's Hand-book of Useful Legal Information for Business Men. 16mo, mor. $5 00 * Davis's Elements of Law 8vo, 2 50 * Treatise on the Military Law of United States 8vo, 7 00 * Dudley's Military Law and the Procedure of Courts-martial. .Large 12mo, 2 50 Manual for Courts-martial 16mo, mor. 1 50 Wait's Engineering and Architectural Jurisprudence 8vo, 6 00 Sheep, 6 50 Law of Contracts 8vo, 3 00 Law of Operations Preliminary to Construction in Engineering and Architecture 8vo, 5 00 Sheep, 5 50 MATHEMATICS. Baker's Elliptic Functions 8vo, 1 50 Briggs's Elements of Plane Analytic Geometry. (Bocher.) 12mo, 1 00 * Buchanan's Plane and Spherical Trigonometry 8vo, 1 00 Byerly's Harmonic Functions 8vo, 1 00 Chandler's Elements of the Infinitesimal Calculus 12mo, 2 00 * Coffin's Vector Analysis 12mo, 2 50 Compton's Manual of Logarithmic Computations 12mo, 1 50 * Dickson's College Algebra Large 12mo, 1 50 * Introduction to the Theory of Algebraic Equations Large 12mo, 1 25 Emch's Introduction to Protective Geometry and its Application 8vo, 2 50 Fiske's Functions of a Complex Variable 8vo, 1 00 Halsted's Elementary Synthetic Geometry 8vo, 1 50 Elements of Geometry. 8vo, 1 75 * Rational Geometry 12mo, 1 50 Synthetic Protective Geometry 8vo, 1 00 * Hancock's Lectures on the Theory of Elliptic Functions 8vo, 5 00 Hyde's Grassmann's Space Analysis 8vo, 1 00 * Johnson's (J. B.) Three-place Logarithmic Tables: Vest-pocket size, paper, 15 * 100 copies, 5 00 * Mounted on heavy cardboard, 8X10 inches, 25 * 10 copies, 2 00 Johnson's (W. W.) Abridged Editions of Differential and Integral Calculus. Large 12mo, 1 vol. 2 50 Curve Tracing in Cartesian Co-ordinates 12mo, 1 00 Differential Equations 8vo, 1 00 Elementary Treatise on Differential Calculus Large 12mo, 1 60 Elementary Treatise on the Integral Calculus Large 12mo, 1 50 * Theoretical Mechanics 12mo, 3 00 Theory of Errors and the Method of Least Squares 12mo, 1 50 Treatise on Differential Calculus Large 12mo, 3 00 ' Treatise on the Integral Calculus Large 12mo, 3 00 Treatise on Ordinary and Partial Differential Equations. . .Large 12mo, 3 50 Karapetoff's Engineering Applications of Higher Mathematics: * Part I. Problems on Machine Design Large 12mo, 75 Koch's Practical Mathematics. (In Press.) Laplace's Philosophical Essay on Probabilities. (Truscott and Emory.) . l^mo, 2 00 * Le Messurier's Key to Professor W. W. Johnson's Differential Equations. Small 8vo, 1 75 * Ludlow's Logarithmic and Trigonometric Tables 8vo, 1 00 * Ludlow and Bass's Elements of Trigonometry and Logarithmic and Other Tables 8vo, 3 00 * Trigonometry and Tables published separately Each, 2 00 Macfarlane's Vector Analysis and Quaternions, 8vo, 1 00 McMahon's Hyperbolic Functions 8vo, 1 00 Manning's Irrational Numbers and their Representation by Sequences and Series 12mo, 1 25 * Martin's Text Book on Mechanics. Vol. I. Statics 12mo, 1 25 * Vol. II. Kinematics and Kinetics 12mo, 1 50 * Vol. III. Mechanics of Materials 12mo, 1 50 12 Mathematical Monographs. Edited by Mansfield Merriman and Robert S. Woodward Octavo, each $1 00 No. 1. History of Modern Mathematics, by David Eugene Smith. No. 2. Synthetic Protective Geometry, by George Bruce Halsted No. 3. Determinants, by Laenas Gifford Weld. No. 4. Hyper- bolic Functions, by James McMahon. No. 5. Harmonic Func- tions, by William E. Byerly. No. 6. Grassmann's Space Analysis, by Edward W. Hyde. No. 7. Probability and Theory of Errors, by Robert S. Woodward. No. 8. Vector Analysis and Quaternions, by Alexander Macfarlane. No. 9. Differential Equations, by William Woolsey Johnson. No. 10. The Solution of Equations, by Mansfield Merriman. No. 11. Functions of a Complex Variable, by Thomas S. Fiske. Maurer's Technical Mechanics. 8vo, 4 00 Merriman's Method of Least Squares 8vo, 2 00 Solution of Equations 8vo, 1 00 * Moritz's Elements of Plane Trigonometry .8vo, 2 00 Rice and Johnson's Differential and Integral Calculus. 2 vols. in one. Large 12mo, 1 50 Elementary Treatise on the Differential Calculus Large 12mo, 3 00 Smith's History of Modern Mathematics 8vo, 1 00 * Veblen and Lennes's Introduction to the Real Infinitesimal Analysis of One Variable 8vo, 2 00 * Waterbury's Vest Pocket Hand-book of Mathematics for Engineers. 21 X 5f inches, mor. 1 00 * Enlarged Edition, Including Tables mor. 1 50 Weld's Determinants 8vo, 1 00 Wood's Elements of Co-ordinate Geometry 8vo, 2 00 Woodward's Probability and Theory of Errors 8vo, 1 00 MECHANICAL ENGINEERING. MATERIALS OF ENGINEERING, STEAM-ENGINES AND BOILERS. Bacon's Forge Practice 12mo, 1 50 Baldwin's Steam Heating for Buildings 12mo, 2 50 Barr and Wood's Kinematics of Machinery 8vo, 2 50 * Bartlett's Mechanical Drawing 8vo, 3 00 Abridged Ed 8vo, 1 50 * Bartlett and Johnson's Engineering Descriptive Geometry 8vo, 1 50 * Burr's Ancient and Modern Engineering and the Isthmian Canal 8vo, 3 50 Carpenter's Heating and Ventilating Buildings 8vo, 4 00 * Carpenter and Diederichs's Experimental Engineering 8vo, 6 00 * Clerk's The Gas, Petrol and Oil Engine 8vo, 4 00 Compton's First Lessons in Metal Working , 12mo, 1 50 Compton and De Groodt's Speed Lathe 12mo, 1 50 Coolidge's Manual of Drawing 8vo, paper, 1 00 Coolidge and Freeman's Elements of General Drafting for Mechanical En- gineers Oblong 4to, 2 50 Cromwell's Treatise on Belts and Pulleys 12mo, 1 50 Treatise on Toothed Gearing 12mo, 1 50 Dingey's Machinery Pattern Making 12mo, 2 00 Durley 's Kinematics of Machines 8vo, 4 00 Flanders's Gear-cutting Machinery Large 12mo, 3 00 Flather's Dynamometers and the Measurement of Power 12mo, 3 00 Rope Driving 12mo, 2 00 Gill's Gas and Fuel Analysis for Engineers 12mo, 1 25 Goss's Locomotive Sparks 8vo, 2 00 * Greene's Pumping Machinery .- 8vo, 4 00 Hering's Ready Reference Tables (Conversion Factors) 16mo, mor. 2 50 * Hobart and Ellis's High Speed Dynamo Electric Machinery 8vo, 6 00 Hutton's Gas Engine 8vo, 5 00 Jamison's Advanced Mechanical Drawing 8vo, 2 00 Elements of Mechanical Drawing 8vo, 2 50 Jones's Gas Engine 8vo, 4 00 Machine Design: Part I. Kinematics of Machinery 8vo, 1 50 Part II. Form, Strength, and Proportions of Parts 8vo, 3 00 13 * Kaup's Machine Shop Practice Large 12mo $1 25 * Kent's Mechanical Engineer's Pocket-Book 16mo, mor. 5 00 Kerr's Power and Power Transmission 8vo, 2 00 * Kimball and Barr's Machine Design 8vo, 3 00 * King's Elements of the Mechanics of Materials and of Power of Trans- mission 8vo, 2 50 * Lanza's Dynamics of Machinery 8vo, 2 50 Leonard's Machine Shop Tools and Methods 8vo, * Levin's Gas Engine 8vo, * Lorenz's Modern Refrigerating Machinery. (Pope, Haven, and Dean). .8vo, MacCord's Kinematics; or, Practical Mechanism 8vo, Mechanical Drawing 4to, Velocity Diagrams 8vo, MacFarland's Standard Reduction Factors for Gases 8vo, Mahan's Industrial Drawing. (Thompson.) 8vo. 3 50 Mehrtens's Gas Engine Theory and Design Large 12mo, 2 50 Miller, Berry, and Riley's Problems in Thermodynamics and Heat Engineer- ing 8vo, paper, 75 Oberg's Handbook of Small Tools Large 12mo, 2 50 * Parshall and Hobart's Electric Machine Design. Small 4to, half leather, 12 50 * Peele's Compressed Air Plant. Second Edition, Revised and Enlarged . 8vo, 3 50 * Perkins's Introduction to General Thermodynamics 12mo. 1 50 Poole's Calorific Power of Fuels 8vo, 3 00 * Porter's Engineering Reminiscences, 1855 to 1882 8vq, 3 00 Randall's Treatise on Heat. (In Press.) * Reid's Mechanical Drawing. (Elementary and Advanced.) 8vo, 2 00 Text-book of Mechanical Drawing and Elementary Machine Design. 8vo, 3 00 Richards's Compressed Air 12mo, 1 50 Robinson's Principles of Mechanism 8vo, 3 00 Schwamb and Merrill's Elements of Mechanism 8vo, 3 00 Smith (A. W.) and Marx's Machine Design 8vo, 3 00 Smith's (O.) Press-working of Metals 8vo, 3 00 Sorel's Carbureting and Combustion in Alcohol Engines. (Woodward and Preston.) Large 12mo, 3 00 Stone's Practical Testing of Gas and Gas Meters 8vo, 3 50 Thurston's Animal as a Machine and Prime Motor, and the Laws of Energetics. 12mo, 1 00 Treatise on Friction and Lost Work in Machinery and Mill Work. . .8vo, 3 00 * Tillson's Complete Automobile Instructor 16mo, 1 50 * Titsworth's Elements of Mechanical Drawing .Oblong 8vo, 1 25 Warren's Elements of Machine Construction and Drawing 8vo, 7 50 * Waterbury's Vest Pocket Hand-book of Mathematics for Engineers. 2 1 X 5f inches, mor. 1 00 * Enlarged Edition, Including Tables mor. 1 50 Weisbach's Kinematics and the Power of Transmission. (Herrmann - Klein.) .8vo, 5 00 Machinery of Transmission and Governors. (Hermann Klein.) . .8vo, 500 Wood's Turbines 8vo, 2 50 MATERIALS OF ENGINEERING. Burr's Elasticity and Resistance of the Materials of Engineering 8vo, 7 50 Church's Mechanics of Engineering 8vo, 6 00 Mechanics of Solids (Being Parts I, IT, III of Mechanics of Engineering). 8vo, 4 50 * Greene's Structural Mechanics 8vo, 2 50 Holley's Analysis of Paint and Varnish Products. (In Press.) * Lead and Zinc Pigments Large 12mo, 3 00 Johnson's (C. M.) Rapid Methods for the Chemical Analysis of Special Steels, Steel-Making Alloys and Graphite Large 12mo, 3 00 Johnson's (J. B.) Materials of Construction 8vo, 6 00 Keep's Cast Iron 8vo, 2 50 * King's Elements of the Mechanics of Materials and of Power of Trans- mission 8vo, 2 50 Lanza's Applied Mechanics 8vo, 7 50 Lowe's Paints for Steel Structures 12mo, 1 00 Maire's Modern Pigments and their Vehicles 12mo, 2 00 14 Maurer's Technical Mechanics 8vo, $4 00 Merriman's Mechanics of Materials 8vo, 5 00 * Strength of Materials 12mo, 1 00 Metcalf 's Steel. A Manual for Steel-users 12mo, 2 00 * Murdock's Strength of Materials 12mo, 2 00 Sabin's Industrial and Artistic Technology of Paint and Varnish 8vo, 3 00 Smith's (A. W.) Materials of Machines 12mo, 1 00 * Smith's (H. E.) Strength of Material 12mo, 1 25 Thurston's Materials of Engineering 3 vols., 8vo, 8 00 Part I. Non-metallic Materials of Engineering, 8vo, 2 00 Part II. Iron and Steel 8vo, 3 50 Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their Constituents 8vo, 2 50 Waterbury's Laboratory Manual for Testing Materials of Construction. (In Press.) Wood's (De V.) Elements of Analytical Mechanics 8vo, 3 00 Treatise on the Resistance of Materials and an Appendix on the Preservation of Timber 8vo, 2 00 Wood's (M. P.) Rustless Coatings: Corrosion and Electrolysis of Iron and Steel 8vo, 4 00 STEAM-ENGINES AND BOILERS. Berry's Temperature-entropy Diagram. Third Edition Revised and En- larged 12mo, 2 50 Carnot's Reflections on the Motive Power of Heat. (Thurston.) 12mo, 1 50 Chase's Art of Pattern Making 12mo, 2 50 Creighton's Steam-engine and other Heat Motors 8vo, 5 00 Dawson's "Engineering" and Electiic Traction Pocket-book. .. . I6mo, mor. 5 00 * Gebhardt's Steam Power Plant Engineering 8vo, 6 00 Goss's Locomotive Performance 8vo, 5 00 Hemenway's Indicator Practice and Steam-engine Economy 12mo, 2 00 Hirshfeld and Barnard's Heat Power Engineering. (In Press.) Hutton's Heat and Heat-engines 8vo, 5 00 Mechanical Engineering of Power Plants 8vo, 5 00 Kent's Steam Boiler Economy 8vo, 4 00 Kneass's Practice and Theory of the Injector 8vo, 1 50 MacCord's Slide-valves 8vo, 2 00 Meyer's Modern Locomotive Construction 4to, 10 00 Miller, Berry, and Riley's Problems in Thermodynamics 8vo, paper, 75 Moyer's Steam Turbine 8vo, 4 00 Peabody's Manual of the Steam-engine Indicator 12mo, 1 50 Tables of the Properties of Steam and Other Vapors and Temperature- Entropy Table 8vo, 1 00 Thermodynamics of the Steam-engine and Other Heat-engines. . . .8vo, 5 00 * Thermodynamics of the Steam Turbine 8vo, 3 00 Valve-gears for Steam-engines 8vo, 2 50 Peabody and Miller's Steam-boilers 8vo, 4 00 * Perkins's Introduction to General Thermodynamics 12mo. 1 50 Pupin's Thermodynamics of Reversible Cycles in Gases and Saturated Vapors. (Osterberg.) 12mo, 1 25 Reagan's Locomotives: Simple, Compound, and Electric. New Edition. Large 12mo, 3 50 Sinclair's Locomotive Engine Running and Management 12mo, 2 00 Smart's Handbook of Engineering Laboratory Practice 12mo, 2 50 Snow's Steam-boiler Practice '. . . .8vo, 3 00 Spangler's Notes on Thermodynamics 12mo, 1 00 Valve-gears 8vo, 2 50 Spangler, Greene, and Marshall's Elements of Steam-engineering 8vo, 3 00 Thomas's Steam-turbines 8vo, 4 00 Thurston's Handbook of Engine and Boiler Trials, and the Use of the Indi- cator and the Prony Brake 8vo, 5 00 Handy Tables 8vo, 1 50 Manual of Steam-bv lers, their Designs, Construction, and Operation 8vo, 5 00 Manual of the Steam-eng : -^e 2 vols., 8vo, 10 00 Part I. History, Structure, and Theory 8vo, 6 00 Part II. Design, Construction, and Operation 8vo, 6 00 15 Wehrenfennig's Analysis and Softening of Boiler Feed-water. (Patterson ) 8vo, $4 00 Weisbach's Heat, Steam, and Steam-engines. (Du Bois.) 8vo, 5 00 Whitham's Steam-engine Design 8vo. 5 00 Wood's Thermodynamics, Heat Motors, and Refrigerating Machines. . .8vo, 4 00 MECHANICS PURE AND APPLIED. Church's Mechanics of Engineering .8vo, 6 00 Mechanics of Fluids (Being Part IV of Mechanics of Engineering). . 8vo, 3 00 * Mechanics of Internal Work 8vo, 1 50 Mechanics of Solids (Being Parts I, II, III of Mechanics of Engineering). 8vo, 4 50 Notes and Examples in Mechanics 8vo, 2 00 Dana's Text-book of Elementary Mechanics for Colleges and Schools .12mo, 1 50 Du Bois's Elementary Principles of Mechanics: Vol. I. Kinematics 8vo, 3 50 Vol. II. Statics 8vo, 4 00 Mechanics of Engineering. Vol. I Small 4to, 7 50 Vol. II Small 4to, 10 00 * Greene's Structural Mechanics 8vo, 2 50 * Hartmann's Elementary Mechanics for Engineering Students 12mo, 1 25 James's Kinematics of a Point and the Rational Mechanics of a Particle. Large 12mo, 2 00 * Johnson's (W. W.) Theoretical Mechanics 12mo, 3 00 * King's Elements of the Mechanics of Materials and of Power of Trans- mission 8vo, 2 50 Lanza's Applied Mechanics 8vo, 7 50 * Martin's Text Book on Mechanics, Vol. I, Statics 12mo, 1 25 * Vol. II. Kinematics and Kinetics 12mo, 1 50 * Vol. III. Mechanics- of Materials 12mo, 1 50 Maurer's Technical Mechanics 8vo. 4 00 * Merriman's Elements of Mechanics 12mo, 1 00 Mechanics of Materials 8vo, 5 00 * Michie's Elements of Analytical Mechanics 8vo, 4 00 Robinson's Principles of Mechanism 8vo, 3 00 Sanborn's Mechanics Problems Large 12mo, 1 50 Schwamb and Merrill's Elements of Mechanism 8vo, 3 00 Wood's Elements of Analytical Mechanics 8vo, 3 00 Principles of Elementary Mechanics. 12mo, 1 25 MEDICAL. * Abderhalden's Physiological Chemistry in Thirty Lectures. (Hall and Defren.) 8vo, 5 00 von Behring's Suppression of Tuberculosis. (Bolduan.) 12mo, 1 00 * Bolduan's Immune Sera 12mo, 1 50 Bordet's Studies in Immunity. (Gay.) 8vo, 6 00 * Chapin's The Sources and Modes of Infection Large 12mo, 3 00 Davenport's Statistical Methods witlx Special Reference to Biological Varia- tions 16mo, mor. 1 50 Ehrlich's Collected Studies on Immunity. (Bolduan.) 8vo, 6 00 * Fischer's Nephritis Large 12mo, 2 50 * Oedema 8vo, 2 00 * Physiology of Alimentation Large 12mo, 2 00 * de Fursac's Manual of Psychiatry. (Rosanoff and Collins.) . . . Large 12mo, 2 50 * Hammarsten's Text-book on Physiological Chemistry. (Mandel.).. . .8vo, 4 00 Jackson's Directions for Laboratory Work in Physiological Chemistry. .8vo. 1 25 Lassar-Cohn's Praxis of Urinary Analysis. (Lorenz.) 12mo, 1 00 Mandel's Hand-book for the Bio-Chemical Laboratory 12mo. 1 50 * Nelson's Analysis of Drugs and Medicines 12mo, 3 00 * Pauli's Physical Chemistry in the Service of Medicine. (Fischer.) ..12mo, 1 25 * Pozzi-Escot's Toxins and Venoms and their Antibodies. (Cohn.). . 12mo, 1 00 Rostoski's Serum Diagnosis. (Bolduan.) 12mo, 1 00 Ruddiman's Incompatibilities in Prescriptions 8vo, 2 00 Whys in Pharmacy 12rao, 1 00 Salkowski's Physiological and Pathological Chemistry. (Orndorff.) .. ..8vo, 2 50 16 * Satterlee's Outlines of Human Embryology 12mo, $1 25 Smith's Lecture Notes on Chemistry for Dental Students 8vo, 2 50 * Whipple's Tyhpoid Fever Large 12mo, 3 00 * Woodhull's Military Hygiene for Officers of the Line Large 12mo, 1 50 * Personal Hygiene 12mo, 1 00 Worcester and Atkinson's Small Hospitals Establishment and Maintenance, and Suggestions for Hospital Architecture, with Plans for a Small Hospital 12mo, 1 25 METALLURGY. Betts's Lead Refining by Electrolysis 8vo, 4 00 Holland's Encyclopedia of Founding and Dictionary of Foundry Terms used in the Practice of Moulding 12mo. 3 00 Iron Founder 12mo, 2 50 " " Supplement 12mo, 2 50 * Borchers's Metallurgy. (Hall and Hayward.) 8vo, 3 00 * Burgess and Le Chatelier's Measurement of High Temperatures. Third Edition 8vo, 4 00 Douglas's Untechnical Addresses on Technical Subjects 12mo, 1 00 Goesel's Minerals and Metals: A Reference Book 16mo, mor. 3 00 * Iles's Lead-smelting 12mo, 2 50 Johnson's Rapid Methods for the Chemical Analysis of Special Steels, Steel-making Alloys and Graphite Large 12mo, 3 GO Keep's Cast Iron 8vo, 2 50 Metcalf 's Steel. A Manual for Steel-users 12mo, 2 00 Minet's Production of Aluminum and its Industrial Use. (Waldo.). . 12mo, 2 50 * Palmer's Foundry Practice ' -Large 12mo, 2 00 * Price and Meade's Technical Analysis of Brass 12mo, 2 00 * Ruer's Elements of Metallography. (Mathewson.) : . . .8vo, 3 00 Smith's Materials of Machines 12mo, 1 00 Tate and Stone's Foundry Practice 12mo, 2 00 Thurston's Materials of Engineering. In Three Parts 8vo, 8 00 Part I. Non-metallic Materials of Engineering, see Civil Engineering, page 9. Part II. Iron and Steel 8vo, 3 50 Part III. A Treatise on Brasses, Bronzes, and Other Alloys and their Constituents 8vo, 2 50 Ulke's Modern Electrolytic Copper Refining 8vo, 3 00 West's American Foundry Practice 12mo, 2 50 Moulders' Text Book. . . . 12mo. 2 50 MINERALOGY. * Browning's Introduction to the Rarer Elements 8vo, 1 50 Brush's Manual of Determinative Mineralogy. (Penfield.) 8vo, 4 00 Butler's Pocket Hand-book of Minerals 16mo, mor. 3 00 Chester's Catalogue of Minerals 8vo, paper, 1 00 Cloth, 1 25 * Crane's'Gold and Silver 8vo, 5 00 Dana's First Appendix to Dana's New "System of Mineralogy". .Large 8vo, 1 00 Dana's Second Appendix to Dana's New " System of Mineralogy." Large 8vo, 1 50 Manual of Mineralogy and Petrography 12mo, 2 00 Minerals and How to Study Them 12mo, 1 50 System of Mineralogy Large 8vo, half leather, 12 50 Text-book of Mineralogy 8vo, 4 00 Douglas's Untechnical Addresses on Technical Subjects 12mo, 1 00 Eakle's Mineral Tables 8vo, 1 25 * Eckel's Building Stones and Clays 8vo, 3 00 Goesel's Minerals and Metals: A Reference Book. 16mo, mor. 3 00 * Groth's The Optical Properties of Crystals. (Jackson.) 8vo, 3 50 Groth's Introduction to Chemical Crystallography (Marshall) 12mo, 1 25 * Hayes's Handbook for Field Geologists. 16mo, mor. 1 50 Iddings's Igneous Rocks 8vo, 5 00 Rock Minerals 8vo, 5 00 17 Johannsen's Determination of Rock-forming Minerals in Thin Sections. 8vo, With Thumb Index $5 00 * Martin's Laboratory Guide to Qualitative Analysis with the Blow- pipe ^ 12mo, 60 Merrill's Non-metallic Minerals: Their Occurrence and Uses 8vo, 4 00 Stones for Building and Decoration 8vo, 5 00 * Penfield's Notes on Determinative Mineralogy and Record of Mineral Tests. 8vo, paper, 50 Tables of Minerals, Including the Use of Minerals and Statistics of Domestic Production 8vo, 1 00 * Pirsson's Rocks and Rock Minerals 12mo, 2 50 * Richards's Synopsis of Mineral Characters 12mo, mor. 1 25 * Ries's Clays: Their Occurrence, Properties and Uses 8vo, 5 00 * Ries and Leighton's History of the Clay-working industry of the United States .8vo. 2 50 * Rowe's Practical Mineralogy Simplified 12mo, 1 25 * Tillman's Text-book of Important Minerals and Rocks , 8vo, 2 00 Washington's Manual of the Chemical Analysis of Rocks 8vo, 2 00 MINING. * Beard's Mine Gases and Explosions Large 12mo, 3 00 * Crane's Gold and Silver 8vo, 5 00 * Index of Mining Engineering Literature 8vo, 4 00 * 8vo, mor. 5 00 * Ore Mining Methods 8vo, 3 00 * Dana and Saunders's Rock Drilling 8vo, 4 00 Douglas's Untechnical Addresses on Technical Subjects 12mo, 1 00 Eissler's Modern High Explosives 8vo, 4 00 Goesel's Minerals arid Metals: A Reference Book 16mo, mor. 3 00 Ihlseng's Manual of Mining 8vo, 5 00 * Iles's Lead Smelting 12mo, 2 50 * Peele's Compressed Air Plant 8vo, 3 50 Riemer's Shaft Sinking Under Difficult Conditions. (Corning and Peele.)8vo, 3 00 * Weaver's Military Explosives 8vo, 3 00 Wilson's Hydraulic and Placer Mining. 2d edition, rewritten 12mo, 2 50 Treatise on Practical and Theoretical Mine Ventilation 12mo, 1 25 SANITARY SCIENCE. Association of State and National Food and Dairy Departments, Hartford Meeting, 1906 8vo, 3 00 Jamestown Meeting, 1907 8vo, 3 00 * Bashore's Outlines of Practical Sanitation 12mo, 1 25 Sanitation of a Country House 12mo, 1 00 Sanitation of Recreation Camps and Parks 12mo, 1 00 * Chapin's The Sources and Modes of Infection Large 12mo, 3 00 Folwell's Sewerage. (Designing, Construction, and Maintenance.) 8vo, 3 00 Water-supply Engineering 8vo, 4 00 Fowler's Sewage Works Analyses 12mo, 2 00 Fuertes's Water-filtration Works 12mo, 2 50 Water and Public Health 12mo, 1 50 Gerhard's Guide to Sanitary Inspections 12mo, 1 50 * Modern Baths and Bath Houses 8vo, 3 00 Sanitation of Public Buildings 12mo, 1 50 * The Water Supply, Sewerage, and Plumbing of Modern City Buildings. 8vo, 4 00 Hazen's Clean Water and How to Get It Large 12mo, 1 50 Filtration of Public Water-supplies 8vo, 3 00 * Kinnicutt, Winslow and Pratt's Sewage Disposal 8vo, 3 00 Leach's Inspection and Analysis of Food with Special Reference to State Control 8vo, 7 50 Mason's Examination of Water. (Chemical and Bacteriological) 12mo, 1 25 Water-supply. (Considered principally from a Sanitary Standpoint). 8vo, 4 00 * Mast's Light and the Behavior of Organisms Large 12mo, 2 50 18 * Merriman's Elements of Sanitary Engineering 8vo, $2 00 Ogden's Sewer Construction 8vo, 3 00 Sewer Design 12mo, 2 00 Parsons's Disposal of Municipal Refuse 8vo, 2 00 Prescott and Winslow's Elements of Water Bacteriology, with Special Refer- ence to Sanitary Water Analysis 12mo, 1 50 * Price's Handbook on Sanitation 12mo, 1 50 Richards's Conservation by Sanitation / 8vo, 2 50 Cost of Cleanness 12mo, 1 00 Cost of Food. A Study in Dietaries 12mo, 1 00 Cost of Living as Modified by Sanitary Science 12mo, 1 00 Cost of Shelter 12mo, 1 00 Richards and Woodman's Air, Water, and Food from a Sanitary Stand- point 8vo, 2 00 * Richey's Plumbers', Steam-fitters', and Tinners' Edition (Building Mechanics' Ready Reference Series) 16mo, mor. 1 50 Rideal's Disinfection and the Preservation of Food 8vo, 4 00 Soper's Air and Ventilation of Subways 12mo, 2 50 Turneaure and Russell's Public Water-supplies , 8vo, 5 00 Venable's Garbage Crematories in America 8vo, 2 00 Method and Devices for Bacterial Treatment of Sewage 8vo, 3 00 Ward and Whipple's Freshwater Biology. (In Press.) Whipple's Microscopy of Drinking-water 8vo, 3 50 * Typhoid Fever Large 12mo, 3 00 Value of Pure Water Large 12mo, 1 00 Winslow's Systematic Relationship of the Coccaceae Large 12mo, 2 50 MISCELLANEOUS. * Burt's Railway Station Service 12mo, 2 00 * Chapin's How to Enamel 12mo. 1 00 Emmons's Geological Guide-book of the Rocky Mountain Excursion of the International Congress of Geologists Large 8vo, 1 50 Fen-el's Popular Treatise on the Winds 8vo, 4 00 Fitzgerald's Boscon Machinist 18mo, 1 00 * Fritz, Autobiography of John 8vo, 2 00 Gannett's Statistical Abstract of the World 24mo, 75 Haines's American Railway Management 12mo, 2 50 Hanausek's The Microscopy of Technical Products. (Win ton) 8vo, 5 00 Jacobs's Betterment Briefs. A Collection of Published Papers on Or- ganized Industrial Efficiency 8vo, 3 50 Metcalfe's Cost of Manufactures, and the Administration of Workshops.. 8 vo, 5 00 * Parkhurst's Applied Methods of Scientific Management 8vo, 2 00 Putnam's Nautical Charts 8vo, 2 00 Ricketts's History of Rensselaer Polytechnic Institute 1824-1894. Large 12mo, 3 00 * Rotch and Palmer's Charts of the Atmosphere for Aeronauts and Aviators. Oblong 4to, 2 00 Rotherham's Emphasised New Testament Large 8vo, 2 00 Rust's Ex-Meridian Altitude, Azimuth and Star-finding Tables 8vo 5 00 Standage's Decoration of Wood, Glass, Metal, etc 12mo 2 00 Thome's Structural and Physiological Botany. (Bennett) 16mo, 2 25 Westermaier's Compendium of General Botany. (Schneider) 8vo, 2 00 Winslow's Elements of Applied Microscopy 12mo, 1 50 HEBREW AND CHALDEE TEXT-BOOKS. Gesenius's Hebrew and Chaldee Lexicon to the Old Testament Scriptures. (Tregelles.) Small 4to, half mor, 5 00 Green's Elementary Hebrew Grammar 12mo 1 25 19 THIS BOOK IS DUE ON THE LAST DATE STAMPED BELOW AN INITIAL FINE OF 25 CENTS WILL BE ASSESSED FOR FAILURE TO RETURN THIS BOOK ON THE DATE DUE. THE PENALTY WILL INCREASE TO SO CENTS ON THE FOURTH DAY AND TO $1.OO ON THE SEVENTH DAY OVERDUE. 8EO.CIRL 190(1*64^8 3 LO LD 21-100m-8,'34 257977