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I 
 
 UNIVERSITY OF NEVADA 
 
 BULLETIN OF THE DEPARTMENT OF 
 GEOLOGY AND MINING. 
 
 Vol. 1, No. 1. June. 1904, 
 
 PRELIMINARY REPORT 
 
 ON THE 
 
 BUILDING STONES OF NEVADA, 
 
 INCLUDING A BRIEF CHAPTER ON 
 
 ROAD METAL. 
 
 JOHN A. REID. 
 
 1904.' 
 

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Table of Contents. 
 
 CHAPTER I. 
 
 Introduction : Need for knowledge and use of stone ; uses of 
 rocks ; arrangement of context. 
 
 CHAPTER II. 
 
 Rocks : Their nature and classification. The igneous rocks ; their 
 occurrence and general classification : plutonic, intermediate, 
 and volcanic; acid and basic. The tuffs; the atmospheric 
 rocks, eolian and aqueous, including sedimentary, organic 
 and chemical rocks. The metamorphic rocks with their divis- 
 ions. 
 
 CHAPTER III. 
 
 Qualities of building stones. Changes in rocks : physical and chem- 
 ical. Rock characteristics : color, hardness, strength, structure, 
 texture, mineral content. Observations on rocks: quarry, 
 buildings, chemical, physical. 
 
 CHAPTER IV. 
 
 Building stones of Nevada : Granites, diorites, rhyolites, andesites, 
 tuffs, sandstones, marbles, travertine. Characteristics, uses, 
 location and availability of each. 
 
 CHAPTER V. 
 
 Road Metal and some General Principles of Road Making. Agents 
 destructive of roads ; selection of materials to withstand these ; 
 kinds of roads for different traffic requirements. Necessary 
 qualities in road metal. Materials available in Nevada. List 
 of references on the subject. 
 
 CHAPTER VI. 
 
 Conclusion: Need of more work on development of State and of 
 more exact knowledge regarding the resources. 
 
 333114 
 
. 
 
 
 
INTRODUCTION. 
 
 CHAPTER I. 
 
 The statement that the West is undeveloped is undeniably 
 true. It is doubly true of the State of Nevada. Little has been 
 done to develop her natural resources ; little is known of the bound- 
 less wealth of her mountains and valleys. Yet Nevada is; on the 
 eve of a great awakening ; with the advent of irrigation thousands 
 of acres of fertile land, now desert like, will be made to, yield an 
 abundance of the fruits of the field, and will support a la'ige pop- 
 ulation. As the community increases in numbers, a demand will 
 arise for all modern improvements, among which two of the .most 
 important are, permanent buildings and good roads. It is needless 
 to state that both of these are made possible by the use,, of,, stone ; 
 stone for erecting substantial, handsome structures, and stone 
 for the betterment of the highways, which are so important to the 
 healthy life of a growing community. It is not needless, however, 
 to state that the principle underlying the choice and use of stone 
 for the above purposes are little understood. Moreover, were 
 these principles understood, little is known of the various rocks 
 in the state available at present. The purpose of this preliminary 
 report, then, is as follows : First, to present the main principles 
 governing the selection and use of building stones and road metal ; 
 second, to describe briefly the stones now in use, or that can easily 
 be used, in Nevada, -with their location and availability; and third, 
 to attempt to arouse a larger interest in a subject of sucjh vast 
 importance to a healthy commonwealth, 
 
 We in the West are prone to build for the day only ; : tomor- 
 row is allowed to care for itself. This is undoubtedly ^cheaper at 
 any particular time, but is far dearer in the end. The scale ;of any 
 civilization may be told from its architecture ; the stability of that 
 civilization is shown by the materials used in the architecture, 
 lint we are learning to build, not for mere decades, but for cen- 
 turies of use, and to do this we must use stone. The first cost 
 may be high, but the ultimate expense is low. The result ^of this 
 is to be seen now in many places. Not only are stone buildings 
 more common, but also the use of stone is seen in bridges, cul- 
 verts, roads, curbing, and in many other ways too numerous to 
 mention. In a rapidly growing state like Nevada the importance 
 of these considerations cannot easily be overestimated, yet that 
 importance is little realized. The frontier town is one of tents 
 
and temporary light wooden buildings. Everything is done with 
 the greatest haste, and calculated to bring in the largest returns 
 for the least expenditure. Every western town has gone through 
 such a period in its growth. After this first newness has worn 
 off a bit, more stable conditions obtain, and almost imperceptably 
 more solid and substantial structures appear, to take the place of 
 the first flimsy ones. In mountainous regions such as Nevada, 
 men have turned instinctivelv to the rocks in the. hills for build- 
 ing materials. As a consequence nearly all of the towns of the 
 state show one or more stone buildings, while in the larger ones, 
 as Reno and^ Virginia City, brick is common also as a material of 
 construction. Yet even with brick structures, stone is required for 
 cornices, arches, and similar uses. The people need to know 
 something about the proper and improper use of these materials, 
 which of course, is the reason for the writing of this report. 
 
 The nature of this subject is more complex than appears on 
 casual inspection. Fundamental principles of three separate 
 sciences all play an essential part; the subject is built upon geol- 
 ogy, physics and chemistry. The practical man may believe that 
 he has no time for such considerations, yet the simplest rule of 
 thumb method, if it be right, is founded upon true scientific prin- 
 ciples. No man in this advancing age of competition can afford 
 to be ignorant of those things which vitally concern him and his 
 business. Every citizen, directly or indirectly, is concerned with 
 the erection of public buildings, private buildings, and county and 
 city highways. Hampered by lack of facilities for detailed work, a 
 full report on the subject is impossible for some time, yet the time is 
 ripe for a little knowledge to be distributed about these matters. 
 
 The chief uses of rock are as follows, in order of their rel- 
 ative importance. First, the largest amount ot stone is used in 
 the construction of buildings, under conditions already mentioned. 
 Second, much of the finest grade of stone is used for monument- 
 al and ornamental work. It is not right, nor is it necessary, that 
 nearly all of oilr rocks for such uses come from outside localities. 
 Third, the importance of crushed rock for the construction of 
 roads is well known. Fourth, in the larger towns and cities, stone 
 curbing is imperative on the graded streets. Fifth, the use of cut 
 stone for bridges and culverts, especially by the railroads, is grow- 
 ing constantly. Sixth, much cut rock is used for sidewalks and 
 by the railroads. Sixth, much cut rock is used for sidewalks and 
 tiling in the most approved buildings. Besides these, there are 
 many lesser uses, such as the construction of piers, break-waters, 
 darns, retaining walls, with such small uses as hitching posts, 
 
steps, mounting blocks, and the like. And it is worth noting that 
 this list is constantly increasing. 
 
 The text will be divided into five succeeding chapters ; a 
 short chapter on the nature of the various rocks, with their clas- 
 sification ; a second chapter devoted to the qualities of building 
 stones, good and bad ; a third devoted to an account and descrip- 
 tion of the building stones of Nevada ; fourth, a brief chapter on 
 road metal; and lastly a conclusion. 
 
CHAPTER II. 
 
 ROCKS : THEIR NATURE AND CLASSIFICATION. 
 
 To the average man, any rock is either a granite, a porphyry, 
 a sandstone, or a slate; these terms are all embracing. Were it 
 not that this loose use of terms is productive of actual loss in 
 construction, by causing a misunderstanding of the characteris- 
 tics of a stone, with consequent misuse, this chapter would be 
 superfluous. But when such a broad error is made as the use 
 of a partially decomposed volcanic rock, an andesite, under the 
 belief that it was a sandstone, which is a rock not often subject 
 to decomposition, at least in the better grades, the writer feels it 
 necessary to present in some detail the various types of rocks 
 found in the earth. 
 
 The first question naturally arising is this : What is a rock ? 
 A proper definition is as follows : A rock is any material making 
 up an integral part of the earth ; that is, any substance which ex- 
 ists in large enough amount to be considered as constituting an 
 essential portion of the globe. This definition, however, though 
 a strictly scientific one, seems rather too broad for our present 
 needs, for by it the soils, water, ice, and all the soft as well as 
 hard materials, are classified under one great head. Here we are 
 only to consider the hard rocks, or stones, and have use for no 
 others. The definition should be kept in mind, nevertheless, for 
 there is no well defined line between a sand and a sandstone, a 
 clay and a shale, or a gravel and a conglomerate. 
 
 The rocks of the earth are divided into three grand classes, 
 as follows : 
 
 /. The Igneous or Massive Rocks. 
 
 II. The Atmospheric, or Stratified Rocks. 
 
 III. The Metanwrphic, or Changed Rocks. 
 
 Let it be understood that in the following remarks under 
 classification, the chief aim has been to present, to the general 
 reader and practical worker, a mtere outline showing how rocks 
 are grouped. It is utterly impossible to describe a rock without 
 some knowledge of minerals on the part of the reader, hence the 
 following brief attempts at describing each rock must be under- 
 stood as incomplete and greatly limited in scope. It is hoped 
 the descriptions may convey some ideas to the practical man as an 
 aid to his work, as well as act as references for the rocks to be 
 later described. 
 
THE IGNEOUS ROCKS. 
 
 The Igneous Rocks are those made by the agency of heat, 
 that is, have cooled from a molten condition. They are also call- 
 ed the massive rocks, because of their structure, which is, broadly 
 speaking, the same in all directions. Also the term eruptive 
 is applied to them, because of their origin as eruptive molten 
 masses. These rocks occur in several different ways, as fol- 
 lows: 
 
 T. Batholites, or those immense masses of igneous rocks, 
 as granites, which form the axes of our greatest mountain 
 ranges. They are characterized by their great size, their evi- 
 dent position beneath other rocks, and the fact that as far as is 
 known they descend to the deep interior mass of the earth. 
 
 2. Laccolites, or those dome shaped rock masses which 
 have been intruded between layers, or strata, of Other rocks, 
 lifting them up like immense blisters. They differ from bath- 
 olites mainly in the fact that they rest upon other rocks and 
 are smaller in size. 
 
 3. Sheets or Sills, or those occurrences of igneous rocks 
 which lie between other rocks as mere sheets, or on top of them 
 They differ from laccolites in that they are everywhere of about 
 the same thickness and have caused no doming of superin- 
 cumbent rocks. They may have been intruded between other 
 rocks, or poured out upon the surface as lava flows, and are 
 usually more nearly horizontal than vertical. 
 
 4. Dykes, or intrusive masses filling fissures, much as do 
 mineral veins. These dykes usually cut across other rocks, are of 
 great length on the surface compared with their width, and de- 
 scending to unknown depths. They are usually more nearly 
 vertical than horizontal, 
 
 5. Irregular Masses, such as volcanic necks, which are 
 merely the hardened lava in the throat or pipe of an extinct 
 volcano, standing up as a more or less conical mass after the 
 wearing away of the soft cone. Also, we have very irregular 
 bodies of igneous rocks of various sizes and shapes which are 
 intruded into overlying rocks. To these, for lack of a better 
 name, the term "stock" is applied. As a grand division, the 
 igneous rocks are those from which all others are derived. 
 
 CLASSIFICATION.. 
 To handle this subject of rock classification from a popular 
 
standpoint is a delicate task. The principles underlying it can 
 only be partly stated, for obvious reasons. A knowldge of min- 
 eralogy cannot be expected, and all that will be done in what 
 follows is to attempt to render intelligible in the simplest pos- 
 sible manner, the main features of the subject. A working 
 knowledge of the simpler minerals, as quartz, feldspar and 
 mica, will be assumed. 
 
 The igneous rocks are classified along two lines. First, 
 chemically, they range from acid to basic, with all grad- 
 ations between. This variation results in the formation of dif- 
 ferent minerals, so that the chemical rock types have different 
 appearances Secondly, these rocks are classified on a basis of 
 what is called texture. Those which have cooled at great 
 depths from a molten condition have done so slowly, with a 
 result that they are thoroughly crystallized, often coarsely so. 
 On the other hand, those which have cooled on the surface and 
 hence quickly, are glassy, at times being a simple glass. The 
 thoroughly crystalline, deep seated rocks are called plutonic, 
 the glassy, surface ones are called volcanic. Those which have 
 cooled and solidified a short way below the surface are often 
 spoken of as dyke, trap, or intermediate rocks. In accordance 
 with these two lines of difference, then all rocks which have 
 solidified from a molten condition are classified. It will be not- 
 iced that there are, unfortunately, two kinds of intermediate 
 rocks: those chemically intermediate and those occupying a 
 middle position on the basis of crystalline texture. However, 
 when an intermediate rock is mentioned, one of the latter 
 kind will usually be meant, or a dyke rock. The meaning of the 
 various textures may be looked at in this way. A granite, for 
 instance, is the type of an acid plutonic rock. MJelted and 
 cooled rapidly it would form a glassy volcanic rock, and, of 
 course, called a rhyolite. Melted and cooled more slowly, yet 
 not so slowly as a deep seated rock looses its heat, an inter- 
 mediate acid type, with some crystals showing, would result. 
 This rock would be called a quartz-porphyry. A more basic 
 plutonic rock, as a diorite, when similarly treated would yield 
 a volcanic adesite and a dyke phase porphyrite. These facts 
 are embodied in the following table, in which only the few 
 main types are mentioned. The many varieties and sub-types 
 made by the petrographer are not necessary in such a report 
 as this. 
 
TABLE OF CLASSIFICATION. 
 
 
 
 TEXTU R E 
 
 
 COMPOSI T IOIN 
 
 PLUTONIC 
 
 INTERMEDIATE 
 
 VOLCANIC 
 
 Acid 
 
 Granite 
 
 Quartz- Porphyry 
 
 Rhyolite 
 
 
 Syenite 
 
 Porphyry 
 
 Trachyte 
 
 Intermediate 
 
 Diorite 
 
 Porphyrite 
 
 Andesite 
 
 Basic 
 
 Gabbro 
 
 Diabase 
 
 Basalt 
 
 
 
 
 
 Ultrabasic 
 
 Peridotite 
 
 l_l M BU 
 
 RC3 ITE 
 
 A peculiar fact to be noted about these rocks is this : Of 
 the plutonic rocks the acid ones, the granites, are most com- 
 mon throughout the earth, while of the volcanic rocks the 
 basic, the basalts, are best developed. Another fact is to be 
 noted regarding the different names. For reasons not neces- 
 sary to state here the names of the intermediate rocks, quartz- 
 porphyry, porphyry and porphyrite, are being dropped, and the 
 volcanic terms used to cover them. For example, andesites and 
 porphyrites are called merely andesites. 
 
 THE INDIVIDUAL ROCKS 
 
 PLUTONIC. 
 
 All wholly crystalline, often coarsely so. 
 
 1. Granite: The granite family consists of acid rocks, 
 wholly crystalline with a coarse to medium fine grain, and of a 
 grayish or reddish color. Free quartz, in colorless crystals, at 
 times tinged bluish or reddish, is always present. Also a 
 white or reddish feldspar, usually clouded with other whitish 
 substances, and some dark mineral, as brown mica, are to be 
 seen. In some rarer granites only a white mica, besides the 
 quartz and feldspar, is present. The granites are the most 
 easily determined of all the igneous rocks, and can be confused 
 only with one other kind. The feldspar of a true granite con- 
 tains potash, and is comparatively acid. A rock very similar to 
 a granite, a diorite with free quartz, differs only in the nature 
 of the feldspar, which contains, in place of potash, soda and 
 lime, making it more basic. To the eye of any one but a 
 trained observer, the two rocks appear precisely the same, 
 
 showing colorless quartz, white feldspar and some dark mi-n- 
 eral. This diorite with quartz is called a granite-diorite, grano- 
 diorite, or quartz-diorite. 
 
 2. Syenite. The syenite family may be briefly character- 
 
ized as granites without quartz. They are comparatively rare 
 rocks, especially in the western part of the United States. In 
 color they vary about as do the granites, from shades of gray 
 to pinkish or reddish tints. The minerals are simply feldspar 
 and some dark colored ones, as mica or hornblende. 
 
 3. Diorite. Of this family the quartz bearing variety, 
 grano-diorite, has already been mentioned. The other vari- 
 eties are without quartz and more basic than syenites, and 
 have about the same grain as the granites and syenites, though 
 averaging a little finer. The fresh rocks are gray in color 
 typically, but darker than the above mentioned types, and show 
 a white feldspar with some dark mineral, usually hornblende. 
 
 4. Gabbro. The gabbro family is the most basic of the 
 normal plutonic rocks, which are of complex nature. These 
 rocks are often coarser in grain than any yet mentioned, the 
 individual crystals at times being an inch or so in diameter. In 
 general their color is grayish, often with a dark olive green 
 tinge. Other colors are black, brown, green and in some vari- 
 eties white. The minerals present are a white feldspar, often 
 with a greenish stain, and some dark mineral which may be dark 
 green, brown or black. Some types are wholly feldspar, and 
 white in color. The gabbros are rare rocks, particularly in this 
 western region. 
 
 5. Peridotites. These rocks are a peculiar family com- 
 posed entirely of dark minerals. The feldspars are typically 
 absent, hence the rocks are called ultra-basic, for the dark min- 
 erals are usually black, with sometimes a tinge of green. They 
 alter as a rule to the common mineral and rock known as 
 serpentine. 
 
 INTSRMEDIATJE; ROCKS. 
 
 These rocks, with the exception of the diabases, show what 
 is called porphyritic texture. As far as appearances are con- 
 cerned, this texture causes the rocks to show well developed 
 crystals of some mineral set in a paste of fine grained material 
 which usually cannot be resolved into its component parts by 
 the unaided eye. This fine grained paste is called the ground 
 mass ; the well formed crystals set therein are termed pheno- 
 crysts. To the naked eye the different kinds of these intermedi- 
 ate rocks are distinguished by the occurrnce of certain miner- 
 als in well developed crystals and also by the color and general 
 appearance of the ground mass. 
 
They are as follows : 
 
 1. Quartz-porphyry. In this rock are seen crystals of 
 clear colorless quartz, with sometimes feldspar and mica, all set 
 in a ground mass of various shades, from almost black, but sub- 
 transparent, through shades of red, pink and grayish. Tlhis 
 ground mass varies in grain, from that which looks like an 
 exceedingly fine grained granite to apparently almost glassy. 
 However, as with the granites, free quartz is characterictic. 
 Where the ground mass is noticibly granite-like though very 
 fine in grain, the rock is called a granite porphyry. 
 
 2. Porphyry. Often this rock is called an orthoclase 
 porphyry or syenite porphyry, depending upon coarseness of 
 grain. The relations between this rock and syenite is precisely 
 that existing between quartz porphpry and granite. Also por- 
 phyry and quartz porphyry are connected in the same way that 
 syenite and granite are. Free quartz is absent, and the minerals 
 appearing as phenocrysts are feldspar, typically the potash var- 
 iety, orthoclase, with often mica or hornblende. When the 
 ground mass appears fine crystalline to the unaided eye the 
 rcok may be called a syenite porphyry. As a rule the rock 
 looks much the same as quartz porphyry, differing in that free 
 quartz is absent and replaced by white or glassy feldspar. 
 
 3. Porphyrite. These rocks are the chemical equals of the 
 diorites, but having cooled near the surface, lack their crystalline 
 texture. They are usually much darker rocks than the preced- 
 ing, showing well developed crystals phenocrysts of typical- 
 ly a dark mineral, but sometimes a white feldspar, in a dark 
 gray, dark green, or even black, ground mass. As with the 
 first two types of intermediate rocks, when the ground mass 
 appears finely crystalline we may have a diorite porphyry. 
 These rocks often assume a reddish hue when weathered. 
 
 4. Diabases. These rocks are the equivalent of the gab- 
 bros, occuring typically as dykes and laccolites. They con- 
 stitute the greatest body of dyke forming rocks known. They 
 are seldom porphyritic, differing from the preceding but are 
 wholly crystalline, appearing on casual observation like fine 
 grained diorites. There are, however, some differences of note. 
 As with the diorites they are composed of a light mineral and 
 a dark one, but the dark one usually has a dark green tinge and 
 a greasy luster seldom present in the black mineral of the 
 diorites. Also, the white feldspar in the true diabases is seen to 
 
be in well formed crystals with the dark mineral crystallized 
 around and between. The reverse is- true with the other wholly 
 crystalline rocks ; the black mineral shpws the best crystal form, 
 with the white feldspar in the spaces between. 
 
 VOLCANIC ROCKS. 
 
 These rocks constitute the lavas, or surface flows of molten 
 rock. In texture they range from porphyritic to glassy; chem- 
 ically they cover the same range as the plutonic rocks, from acid 
 to basic. The common term "obsidian' means a volcanic glass 
 of any chemical constitution whatever. Being cooled lava 
 flows they often show what are called flow or fluxion lines. 
 Their varieties are below, and it is to be remembered that these 
 names are now used to cover both volcanic and intermediate 
 types of rocks. 
 
 i. Rhyolite. These rocks are the most acid of the lavas, 
 corresponding chemically to the granites. In color they are 
 usually various shades of white, gray, blue, pink or green, but 
 are always of light tints except the obsidians, which may ap- 
 pear dark. When porphyritic, they look like quartz-porphyries, 
 into which they shade by insensible gradations, always showing 
 free quartz. When no crystals of any kind are to be seen, yet 
 if the rock is not all glass, their typical white or whitish color 
 serves to distinguish them. The old term felsite is often given 
 to these white varieties which are too fine grained to show any 
 well formed crystals. 
 
 2. Trachyte. The trachytes are much like the rhyolites 
 in appearance, but differ in showing no free quartz. The only 
 minerals showing are typically white or glassy feldspar with 
 sometimes a small amount of the darker varieties. They have 
 usually a characterictic rough feel, hence the name trachyte, 
 which means rough. Specifically, their color is often white, 
 varying to shades of pinkish white or green. The whiteness is 
 more pronounced than in the rhyolites because of the absence of 
 glassy quartz. The trachyte obsidians, like the rhyolitic ones, 
 are darker, often black in large fragments. The family as a 
 whole is a rare one. 
 
 Andesite. This family of rocks is much darker than 
 the two volcanic groups already mentioned. The color ranges 
 from a fairly light gray to a black, a dark gray being an average 
 hue. The well formed crystals the phenocrysts show 
 both light and dark in color. Some andesites show black 
 
crystals in a light gray ground mas,s, while others show white 
 feldspars in a dark gray or black ground mass. In some vari- 
 eties the feldspars are glassy, resembling quartz on cursory in- 
 spection. Quartz does occur in one variety, known as dacite 
 This rock bears the same relation to an andesite that a quartz- 
 diorite does to a diorite. At time an andesite shows no crystals 
 to the unaided eye, when its color is nearly black, much like a 
 basalt. A noteworthy fact is that these rocks tend to weather a 
 dark red color, due to the iron oxide formed by atmospheric agen- 
 cies. 
 
 4. Basalt. These common volcanic rocks are prevailingly 
 black or nearly so. They show discernable crystals less offten 
 than the above types, and are usually finer grained and more 
 homogeneous in appearance. However, in some common var- 
 ieties small grains of a light greenish mineral appear on close 
 inspection the mineral olivene and again, at times crystals of 
 black color are apparent in the dark ground mass. A feature of 
 these rocks and of the andesites as- well, is the weathering or 
 spliting into so-called "basaltic columns.' The rock mass parts 
 01 cleaves into long prisms, roughly hexagonical in cross section, 
 forming a cluster of natural columns. 
 
 5. Limbiirgite. This rare and unimportant family of vol- 
 canic and intermediate rocks is mentioned merely to complete 
 the account of the massive igneous rocks. This family is com- 
 posed entirely of dark minerals set in a paste of the same or of 
 glass with identical chemical composition. The color therefore 
 is black or greenish black when fresh, weathering to a dark red. 
 
 THE TUFFS AND AGGUDM RATS. 
 
 Thus far have been listed only the massive igneous rocks ; 
 there is a minor group of rocks formed by fire agencies, of 
 much less geological importance, but of considerable value as 
 building material. This group is constituted by the fragmental 
 igneous rocks, or tuffs and agglomerates. 
 
 i. Tuffs. These rocks are volcanic ashes and cinders 
 more or less consolidated into firm stone. They are composed 
 of finely divided glassy substances, rock fragments of the vari- 
 ous igneous rocks, and often with mineral grains and large 
 pieces of stone. They are named in accordance with the chem- 
 ical family to which they belong. Thus, there are (i) rhyolite 
 tuffs; (2) trachyte tuffs; (3) andesite tuffs, and (4) basalt 
 tuffs. The rhyolite tuffs are most common. 
 
2. Breccia. This variety of fragmental rock is composed 
 of pieces angular in shape and varied in size, usually of only one 
 kind of rock. They differ from tuffs in that they are not ashes, 
 but made up of rock fragments of some size, and have origin- 
 ated either by the explosive action of a volcano or the crushing 
 effect of pressure exerted in the earth's crust. The fragments 
 are usually cemented by a paste of the same material, finer in 
 grain. 
 
 3. Agglomerate. This rock is most simply described as a 
 mixture of various kinds of volcanic rocks in the form of semi- 
 angular or rounded boulders, small pieces and even ashes. 
 Many agglomerates are hardened volcanic mud containing stones 
 like plums in a pudding. The term is agglomerate, to distin- 
 guish it from conglomerate, which latter term is applied to 
 consolidated gravels deposited by water. Both names mean, 
 however, a mixture of materials. 
 
 THE ATMOSPHERIC ROCKS. 
 
 This grand division of the rocks embraces those which owe 
 their formation, directly or indirectly, to the decomposing action 
 of atmospheric forces on previously existing rocks. Their 
 structure is that called stratified, meaning in beds or layers. The 
 whole division is often called the stratified rocks. But as all the 
 varieties are not truly stratified, the term is not all embracing. 
 In general there are two primary divisions of these rocks, of 
 very unequal importance. They are as follows : 
 
 /. Holian or ^vind formed rocks. 
 II. Aqueous or water formed rocks. 
 
 1. Holian rocks. These rocks are of no importance in 
 the present connection, and will be dismissed with a few words. 
 They consist mainly of those materials piled up by the wind, 
 such as the sand dunes of our coasts. Their recent deposition 
 and geological youth prevent any great amount of consolidation, 
 hence the group needs no further mention. 
 
 2. Aqueous rocks. This group is often called the sedi- 
 mentary, because they are largely composed of sediments de- 
 posited by water action. The name is misleading, for they are 
 not all sedimentary in origin. It can be stated, however, that 
 they have been deposited in or by water. The materials com- 
 posing them are (i) the -residue from the waste of other rocks 
 and derived directly from them; and (2) that material derived 
 
from other rocks by their decomposition, held in solution in 
 water, and deposited either by the action of living organisms or 
 by chemical precipitation. Therefore under this head come 
 two divisions: 
 
 a. Sedimentary Rocks. 
 
 b. Organic and Chemical Rocks. 
 
 Under the action of the atmosphere a rock breaks down in- 
 to soft incoherent material by the leaching out and removal of its 
 soluble parts, leaving an insoluble residue. Thus a granite dis- 
 integrates into a sandy soil, mostly quartz and feldspar, 
 moistened with alkaline water. Ultimately nothing is left but 
 quartz and clay, stained with iron oxide and containing water 
 alkaline with potash, soda and lime. In general it may be stated 
 that quartz and clay are the two least soluble minerals com- 
 monly encountered, and hence, singly or together, mark the end 
 of the decomposition of any rock. It is to be noted that from all 
 rocks except the most acid lime is washed out as well as potash 
 and soda, and the more basic the rock usually the more lime. 
 The alkalies play no particular part in rock building but the lime 
 does. Hence in this brief and popular exposition it may be con- 
 sidered that a decomposed rock will yield quartz sand, clay and 
 a solution of lime. The metallic oxides, such as iron and man- 
 ganese, reman as coloring materials merely, and are of no es- 
 sential importance. However, as few rocks break down into their 
 ultimate products before being consodidated into new rocks, we 
 may expect to find, and do find, nearly all aqueous rocks to be 
 neither pure quartz, pure clay, nor pure lime. Keeping these 
 few facts and causes in mind, the principle varieties will illustrate 
 their results. 
 
 SEDIMENTARY ROCKS. 
 
 1. Conglomerates. These rocks are consolidated gravels, 
 resulting from the wear and tear of waves and currents upon 
 preexisting rocks. The material composing them consists of 
 rounded fragments of various sizes, often cemented by finer 
 material of like nature. These pebbles or boulders, as the case 
 may be, are often of various kinds of rocks, while again they may 
 be all of one sort. 
 
 2. Sandstones. The name of these rocks explains their 
 nature ; a stone built up of grains of sand. The ideal sandstone 
 is composed of grains of pure quartz, representing the last stage 
 
of decay of preexisting rocks. But as most sand is not pure 
 quartz, neither is most sandstone of pi 1 re quartz grains. As a re- 
 sult, these rocks have a variety of colors, depending apon the 
 materials present. The most common rhirurals are quartz, feld- 
 spar, mica f 'kes, garnet and many other dark kinds. There is 
 also another important quality of sandstones. Such rocks are 
 composed of a mass of grains of san^, >il in and cc.-'Vi:tec! bv 
 some other substance. The three important cementing mater- 
 ials are (i) silica or quartz; (2) lime, and (3) iron ozide. Com- 
 binations of these may occur. The first will give a more glassy 
 appearance to the rock and the color will be nearest to that of 
 the original sand grains. The second will give the rock a white 
 color as a rule ; the third will give the stone that red color so de- 
 sired for architectural purposes. 
 
 3. Clay Rocks. The one rock name necessary to name 
 under this head is shale. A clay or mud, when hardened by 
 natural processes, becomes a shale. A pure clay makes a pure 
 shale; a sandy clay a sandy shale, and so on, with all gradations 
 into the sandstone. These rocks are of no value whtever for the 
 purposes of this report, but the clay rocks mentioned under the 
 last grand division of the metamiorphic rocks, the well known 
 slates, are very important. 
 
 ORGANIC AND CHEMICAL ROCKS. 
 
 There are only two varieties of these rocks of any parti- 
 cular value in this discussion. They are these: 
 
 /. Siliceous Rocks. 
 II. Lime Rocks. 
 
 Both owe their origin to the fact that certain minute animals 
 secrete either lime or silica from the water, and on dying their 
 remains accumulate in certain places to form rocks. Also chemi- 
 cal reactions play a part in accumulating both kinds of sub- 
 stances. The first, or siliceous rocks, are formed largely by the 
 growth and depth of certain low forms of life, as sponges ; the 
 second are due in large part to the well known coral polyp. 
 
 I. Siliceous rocks or cherts. These rocks are very fine 
 grained, sometimes almost glassy in appearance, and of various 
 colors from white to red, green and black. They are well known 
 under the name flint or chert. The fact that they are seldom 
 pure silica results in their various shades of color. They are of 
 
no use as building stones, but some have achieved success as 
 road metal. 
 
 2. Lime rocks or limestones. Under this head come the 
 limestones, so well known to everyone. In color they vary from a 
 pure white through the grays to a dead black, the black being due 
 to carbonaceous material. The texture varies from a medium 
 coarse grain to very fine or compact, that is, showing no crystal 
 forms to the naked eye. The crystalline varieties are least com- 
 mon, and are not marbles, which are metamorphic rocks. Tlhe 
 crystals of the limestone are due to simple solution and redeposi- 
 tion, while the marbles owe their crystalline texture to other 
 causes. A drop of a weak acid will always serve to identify the 
 lime rock, as a bubbling of gas is caused. 
 
 METAMORPHIC ROCKS. 
 
 In this division is treated those rocks which have been 
 changed from their original condition by heat and pressure into 
 new forms. They are derived from both the igneous and at- 
 mospheric rocks. Geologically they constitute an extremely 
 important and interesting class; economically they are of little 
 value. A few statements will serve to distinguish the main 
 types. They will be taken up in the following order : 
 
 /. Gneisses and Schists. 
 
 II. Slates and Quartzites. 
 
 III. Marbles and rocks altered chemicallly. 
 
 GNEISSES AND SCHISTS. 
 
 The gneisses are usually rather coarsely crystalline rocks 
 which show a laminated or banded structure due to a flowage 
 under pressure. In mineral content they correspond in most 
 cases with the plutonic rocks, differing from them in the evident 
 structure. A few varieties are derived from the atmospheric 
 rocks, as conglomerates and sandstones. The banded structure 
 i? made evident by the arrangement of minerals in more or less 
 parallel planes. The colors vary precisely as do the colors in the 
 rocks from which the gneisses have been derived. The different 
 varieties are named in a general way from the rock from which 
 the gneiss has originated or resembles most closely. For in- 
 stance, there are granetic gneisses, syenitic gneisses, conglom- 
 erate gneisses an so on. 
 
 The schists*are similar to the gneisses in that they are banded 
 
or laminated, but differ in that these laminations are much finer, 
 giving the rocks the power of splitting along fairly parallel 
 planes. With an elimination of fine distinctions, then the 
 schists are finely laminated or foliated rocks rather fine in grain, 
 with mineral content roughly parallel to that of the gneisses and 
 hence to the plutonic rocks. Their most obvious difference from 
 the gneisses, into which they grade, is in their finer banding. In 
 color they range from white, in the quartz schists to black in the 
 basic varieties. They are named from the dominent mineral 
 showing, which minral is usually arranged in more or less par- 
 allel layers, and causing the rock to split readily along these 
 planes. The schists are derived both from the igneous and the 
 atmospheric rocks. The two chief varieties are the mica-schists, 
 showing bands of brown, black or white mica, and the horn- 
 blende-schists, otherwise called amphibolite-schists or greenstones. 
 None of these are of particular value in this paper. 
 
 SLATES AND QUARTZITES. 
 
 When an ordinary clay rock, or shale, is squeezed under 
 pressure, as often happens in mountain regions, it is made to 
 flow at right angles to this pressure. Certain molecular changes 
 set up in the mass cause it to assume a structure which results 
 in its splitting easily along parallel planes into thin slabs. This 
 structure is called slaty structure, the cleavage is slaty cleavage, 
 and the rocks themselves are slates. They are formed in similar 
 manner from igneous rocks also. The typical slate is not crystal- 
 line ; some varieties show incipient crystallization and shade by 
 insensible gradations into the schists. Their economic import- 
 ance is too well known to need discussion. 
 
 The quartzites are rocks composed chiefly of silica, or 
 quartz. They have usually been derived from siliceous rocks, 
 as quartzose sandstones, by the addition of more silica, binding 
 the whole into a hard, compact mass. Geologically no, old sand- 
 stones frequently are converted into quartzites by long continued 
 action of heat and moisture. Quartz schists and quartzite 
 gneisses, and, in fact, all metamOrphic rocks mainly silica, come 
 under this head. 
 
 MARBLES AND CHEMICALLY ALTERED ROCKS. 
 
 The marbles, properly speaking, are those rocks which have 
 been derived by the crystallization of the limestone by the ac- 
 tion of heat and moisture with perhaps pressure. They are 
 ofter of coarser grain than the crystalline limestones. The pure 
 
varieties are white in color, composed entirely of lime, or lime 
 and magnesia. When made from impure limestones the impur- 
 ities crystallize out as other minerals, of varying shades from 
 white through reds and greens to black. The purer varieties of 
 marble, which are of value for ornamental stones, are of even 
 grain, the crystals showing shining faces. The test with acid 
 always serves to identify these rocks. It is to be noted that 
 there are two kinds of limestones ; ( I ) those composed entirely of 
 lime, and (2) those composed of lime and magnesia. The sec- 
 ond, or lime-magnesia rocks, are called dolomites, or dolomitic 
 limestones, when only a small percentage of magnesia is present. 
 In appearance there is usually no differense ; the dolomites are 
 less acted upon by a cold dilute acid. 
 
 The serpentines are a group of chemically altered rocks of 
 light or dark green to greenish black color, and usually of very 
 fine grain. Sometimes well formed crystals with shiny surfaces 
 are seen set in the finer material. These rocks have resultd from 
 the chemical addition of water to the peridotiles, or ultrabasic 
 plutonic rocks. They are of some value as ornamental stones. 
 
 Steatite, better known as talc and soapstone, is also a 
 chemically altered rock, similiar to serpentine. In color the 
 pure varieties are greasy white, often with a light greenish tinge. 
 They are best known by their greasy feel. Other types of these 
 altered rocks exist, but none of importance in this place. Steatite 
 is often used for furnace foundations and other places where a 
 fire proof material is needed. 
 
 This subject of rock classification is one of great complex- 
 ity and difficulty, particularly in regard to the grand division 
 of the igneous. Necessarily the matter has been presented as 
 one concerned with hard and fast rock varieties, with more or less 
 fixed differences. This is not so, for there are no well defined lines 
 separating any of the various rock types, yet after all, it is the 
 types which are of particular value here, and not the finely drawn 
 conditions and conclusions of petrography. 
 
CHAPTER III. 
 
 QUALITIES OF BUILDING STONES. 
 
 This chapter is divisable, by reason of its nature, into three 
 parts. One speaks of the qualities of a certain stone, with its 
 consequent value for architectural purposes. These qualities are 
 of value, first, because of the inherent power of the stone to re- 
 sist those changes which tend to impair its usefulness, and 
 second, because of the resultant appearance of the rock. These 
 characteristics are estimated in a number of ways. Hence, the 
 divisions of this chapter are as follows : First, an account of 
 the many possible changes to which a building stone may be 
 subjected; second, a description of the features which govern 
 these changes ; and third, a brief notice of the ways in which 
 these these qualities are estimated. The treatment of all this 
 will be brief, a full discussion being reserved for a detailed re- 
 port to be issued at a later date. 
 
 CHANGES IN ROCKS. 
 
 These will be discussed under the following outline: 
 A Physical Changes, due to 
 
 I. Temperature changes. 
 
 II. Mechanical wear and tear. 
 
 III. Effect of pressure. 
 B Chemical Changes, due to 
 
 I. Atmospheric solution. 
 
 II. Decomposition of certain minerals. 
 
 PHYSICAL CHANGES. 
 
 I. Temperature. The results under this division are of 
 two sorts, and due to different qualities in any particular stone 
 The first are those results produced by the alternate expansion 
 and contraction of a rock, and, of course, of its component min- 
 erals, due to heat and cold. This process is the most important 
 method of rock disintegration in regions of little moisture, as in 
 our typical deserts of the west. During the day the stone be- 
 comes warm, or even hot, and expands. At night the temper- 
 ature lowers, the stone contracts, and the changes being usually 
 rather sudden and of unequal amounts in all directions, chips of 
 rock fly off. The Indians use this principle in manufacturing 
 arrowheads. After heating a suitable fragment in a fire, by 
 
touching any desired portion with a drop of cold water, un- 
 equal contraction is produced and a small piece chips off. In 
 regions of equable temperature, as along the western coasts, lit- 
 tle is to be feared from such action ; in Nevada, where the daily 
 changes are often pronounced, some importance is to be attached. 
 The mineral composition and texture of a building stone largely 
 determine how greatly it shall be so acted upon. The loose tex- 
 tured fragmental rocks suffer least, because of their ability to 
 take up without rupture small inequalities of motion in their 
 mass. The massive igneous rocks suffer most because of their 
 internal rigidity and the fact that each one of the constituent 
 minerals expands and contracts differently from the others. The 
 volcanic or partly glassy igneous rocks are probably most liable 
 to such disintegration, the plutonic, because of their inter- 
 locking grains, are less so. 
 
 The second result from temperature changes is due to the 
 freezing of included water. All rocks are porous to a greater or 
 less extent, the crystalline least of all and the fragmental most 
 so. Also the tendency of all rocks to break into large fragments 
 or masses, often rudely regular in shape, by means of parallel 
 cracks, or joint planes, as they are called, allows water to act in 
 this way. The massive rocks especially are subject to jointing* 
 action, which may be either on a large scale or a very minute 
 one. In some instances these joints become apparent only on the 
 weathering of the stone. Water, penetrating the free spaces and 
 cracks in rocks on freezing expands, and exerts a tremendous 
 force acting to disrupt the material. 
 
 2. Mechanical wear and tear. The conditions under 
 which a stone is to be used determines very largely the changes 
 coming under this head. Stones for paving, for tiling, for floors, 
 and for walks, all must be chosen to resist the constant wear of 
 pressing feet and vehicles. Rocks for curbing, subject to hard 
 knocks and the rubbing of wagon tires, must be had resistant to 
 such abrasion. Such stones should be homogeneous and without 
 flaws, otherwise disastrous breakage may occur. Two less im- 
 portant considerations in this connection yet of too great value to 
 omit, are (i) the action of wind, bearing sand and other parti- 
 cles, on the rock of a building; and (2) the erosive and wearing 
 effects of water, particularly in a country of consdierable rain- 
 fall. The hardness, toughness and texture of a building material 
 govern its strength or weakness, of which more will be stated 
 further on. 
 
3. Effects of pressure. The most important consideration 
 here is, obviously, the fact that a stone selected for purposes of 
 construction must be sufficiently strong to withstand all the force 
 applied to it. For buildings not of large size the average stone 
 has strength far above that required ; in large structures some 
 attention must be paid this factor of utility. The effect of pres- 
 sure or strain on a rock is that of crushing, each variety of build- 
 ing material having its own crushing strength, as it is called. 
 These figures, expressed in pounds per square inch mean the 
 force necessary to crush a cube one inch on an edge. Some 
 average figures are as follows : 
 
 Granite 15,000 to 40,000 pounds per square inch. 
 Volcanics 10,000 to 30,000 pounds per square inch. 
 Marble 15,000 to 25,000 pounds per square inch. 
 Sandstone 4,000 to 8,000 pounds per square inch. 
 Tuffs 2,000 to 6,000 pounds per square inch. 
 
 Results both above and below these are often obtained, the 
 hardest granite and rhyolite showing a strength of about 50,000 
 pounds per square inch of surface, while other varieties will 
 crush at a pressure of 10,000 or 12,000 pounds, or even less. In 
 use, a factor of safety, usually of from six to ten, is employed. 
 But there is more to the crushing strength of stone, however. 
 An important relation exists between the strength of a building 
 material and its structure. A limestone or sandstone, for in- 
 stance, is much more able of sustaining a given load when laid 
 parallel to its bedding plane. It is a well known tenet of the 
 masonry trade that a stone should never be laid on edge, par- 
 ticularly one of the sedimentary or laminated rocks. The same 
 holds good in the other rocks, even seemingly structureless gran- 
 ite, for there is often some one direction in which such a rock 
 will cleave or break most easily. This plane should always be 
 laid at right angles to the direction of pressure. Lastly, there 
 is a further consideration growing out of all these facts. All 
 stones are brittle, hence must be handled carefully to avoid shat- 
 tering. The most incipient fractures, of microscopic dimensions, 
 will in time ruin even the hardest rock. Quarrying should be 
 done by the most approved methods, so that this danger of 
 ruining future buildings shall be reduced to a minimum. 
 
CHEMICAL CHANGES 
 
 i. Atmospheric Solution. Under this head comes the mere 
 dissolving out and carrying away of certain parts, or the whole, 
 of a rock. The chief agent of atmospheric action is carbon 
 dioxide or carbonic acid gas, which in time decomposes nearly 
 every rock forming mineral. Marbles, limestones and such rocks 
 dissolve completely. Other rocks, as granite, hctve certain ele- 
 ments leached out, causing a crumbling of the remainder. The 
 alkali metals enter into minerals and compounds which are easily 
 extracted by the water. The decomposition of granite into sand 
 composed of quartz, feldspar and other mineral fragments has 
 been mentioned under the atmospheric rocks. The densest and 
 least porous of the rocks are obviously least libable to this action 
 of solution, and a compact marble, if not broken or shattered 
 in any way, resists for a long time the attack of the atmosphere. 
 In the igneous rocks the iron bearing minerals are easily acted 
 upon and partially leached out. Hence the mineralogical compo- 
 sition of a stone has an important bearing upon its commercial 
 value. 
 
 2. Decomposition of certain minerals. Here will be briefly 
 outlined some noteworthy results produced by the decomposition 
 .of certain minerals. The oxygen and water vapor of the air, 
 combining with the sulphide minerals, such as ordinary pyrite, 
 produce sulphuric acid and iron oxide. This strong acid rapidly 
 attacks the minerals with which it comes in contact, while the 
 iron oxide stains the rock a yellowish or reddish. Pyrite is common 
 in all rocks, and lessens their value for structural purposes in 
 proportion to its relative abundance. An abundance of iron in 
 any rock will cause it in time to become stained a dissagreeable 
 yellow color. There are many other reactions of a similar nature, 
 but of subordinate importance and do not need mentioning. The 
 ultimate value of a stone is greatly influenced by these consider- 
 ations. 
 
 II. ROCK CHARACTERISTICS 
 
 i. Color. This feature of a stone is governed by the col- 
 ors and relative amounts of its component parts and minerals. 
 For instance, .a granite is gray because of the blending of the 
 black mica, white feldspar and colorless quartz. The value of a 
 stone is largely governed by its color, irrespective of other char- 
 acteristics. Other things being equal a red sandstone will be more 
 sought after than a dull gray one; a red granite will often com- 
 
mand a higher price than one with a somber hue. The variation 
 in tint of any particular rock also changes its commercial value, 
 as uniformity in all things is desired. Many stones, otherwise 
 first class, are denied a place in the market because of such a 
 defect. Besides the variation in color of a stone from one point 
 to another, it is also to be noted that on drying or mere exposure 
 to the air, some change in the tint may occur. This may be a 
 deepening of color due to partial oxidization or surface chem- 
 ical change ; again it may be a bleaching due to drying. Often a 
 rock with an abundance of iron assumes a reddish or dark red 
 hue, due to the deposition of iron oxide throughout. Many of the 
 Nevada andesites now used in construction are thus altered. The 
 color is pleasing to the eye, but the stone is weakened in the pro- 
 cess. Sometimes it is less a change of color than a decrease in 
 the luster of a rock surface. This effect is common on granites, 
 whose materials become either slightly altered on thier exposed 
 parts, or covered by a film of dust. 
 
 For ornamental work, as in cornices and monuments, the 
 ability of a stone to show a contrast between the appearances of 
 its polished and rough hewed surfaces is of great value. The 
 crystalline rocks possess this power in the highest degree, because 
 of the fine polish possible. When such materials are carved and 
 their exteriors smoothed, the contrast lies in the fact that a broken 
 surface reflects more white light, while the ponshed surface, 
 which exhibits the colors of the minerals, absorb more of the 
 sun's rays. A certain granite, valuable as) a building material 
 and monumental stone, polishes a very dark gray, while roughing 
 to a light or whitish gray tint. 
 
 The selection of color is mainly from two standpoints : taste 
 or fashion, and utility. In regard to taste, there is nothing to 
 state from the view point of this paper except that, other things 
 being equal, a warm tint is preferable to a colder one. Concern- 
 ing utility, it needs to be emphasized that certain colors are more 
 suitable for particular localities, as, for instance, a gray sandstone 
 should be selected for a building in a manufacturing center, 
 where smoke, dust and grime are ever present. And oil the other 
 hand, white stones should be used only where least exposed to 
 tarnish. 
 
 2. Hardness. The hardhess of a stone is its resistance to 
 abrasion, shown usually by resistance to rubbing. Necessarily, 
 the most important characteristic of a rock underlying this is its 
 mineralogical content, a rock containing an abundance of thte 
 
harder minerals, as quartz, being the hardest, and, as all minerals 
 vary in hardness, their relative abundance, state of aggregation, 
 and size of crystals, govern the resistance of a stone to abrasion. 
 A sandstone composed of grains of hard quartz may be very soft 
 because of the loose hold they have upon one another. The chief 
 reason for the greater hardness of the plutonic rocks is because 
 their component minerals mutually interlock and bind the whole 
 firmly together. Also in the metamorphic quartzites, the little 
 broken pieces of quartz have grown by the addition of more 
 silica until a similar interlocking texture is produced. A sand- 
 stone-cemented by lime or iron oxide is softer because the grains 
 do not bind one another together. In all the sedimentary and 
 laminated rocks variations in hardness may occur in the different 
 layers or laminae caused by a change in any or all of the condi- 
 tions of the minerals mentioned above. As a result, much care 
 must be exercised in their use. In the crystalline and more brit- 
 tle rocks it must be kept in mind that even the slightest shatter- 
 ing by improper handling lowers the hardness and hence the 
 value. 
 
 3. Strength. The strength of a stone is its resistance to ap- 
 plied pressure, either compressive force or transverse strain. 
 This quality is very closely allied to hardnesis and depends in 
 general upon the same internal conditions : mineral content, state 
 of aggregation, and size of grain. As has been pointed out under 
 "effects of pressure," in large structures the power of a stone to 
 sustain a load is of great moment, while in small buildings and 
 other ordinary uses, it matters little. It is not an unusual sight 
 to see in large stone structures that the material near the base 
 shows undoubted signs of crumbling, due to an overload. Every 
 edifice erected is constantly jarred, and this small in- 
 appreciable motion has its lasting effect upon a rock 
 already taxed to sustain a weight too near the limit of safety. 
 More facts pertinent to this matter have been mentioned under 
 "effects of pressure." 
 
 Another characteristic of certain building stones has a direct 
 bearing on both hardness and strength. It is the power of some 
 rocks to harden, or temper, on exposure to the air. In particular, 
 some of the tuffs show an ability to temper to considerable hard- 
 ness, at times sufficient to turn the edge of an ordinary hammer. 
 The last bit of interstitial water of the rock, on working its way 
 out to the surface, deposits whatever it holds in solution in the 
 outer parts of the mass, and at times a perceptable crust is formed, 
 
which, when broken through, exposes the softer stone beneath. 
 Hence a rock once laid and undergoing this process of tempering 
 should not be disturbed. 
 
 4. Structure. Broadly speaking w r e have massive rocks, 
 such as the igneous ; stratified rocks, as the sedimentary ; schistose 
 rocks, and so on. These are, properly speaking, rock structures. 
 There are, also, other structures of the utmost importance. Joints, 
 which have already been mentioned, are common. Irregular 
 cracks and openings of all sizes, down to miscroscopic joints pro- 
 duced by movement and pressure, come likewise under this head. 
 All these determine very largely just how long a stone will last 
 under given conditions. The massive rocks, those whose charac- 
 teristics are constant in all directions, are best fitted for long life ; 
 the stratified or laminated ones are liable to allow rather free ac- 
 cess of water, with resultant deleterious effect, especially if not 
 laid properly. 
 
 5. Texture. The texture of a rock enters largely into the 
 various factors which govern its strength and resistance to 
 change. The different textures, or internal arrangements, have 
 been stated under rock classification, so that but little in the 
 way of reiteration is needed here. A knowledge of the size, ar- 
 rangement, and mutual relations of the minerals or parts of a 
 rock are of the utmost value in estimating the worth of such ma- 
 terial for structural purposes. For reasons given, a porous sand- 
 stone is weaker than a more compact one of the same composi- 
 tion, and should not be used in work requiring any particular 
 strength. In the fragmental rocks the value of the cementing 
 substance is all important. As a general rule it may be stated that 
 the hardest rock is that in which the binding material is of the 
 same nature as the mass. The texture of the plutonic rocks is 
 commonly spoken of as "granitic," because of the similarity with 
 that of true granite ; an interlocking mass of crystals. 
 
 6. Mineral Content. Very little can be written at this time 
 about the various rock forming minerals, because no knowledge 
 of the subject is assumed on the part of the reader. To enter upon 
 a thorough outline of such a matter is beyond the scope of the 
 present paper, and will be reserved for a later date. Quartz, feld- 
 spar, mica, and hornblende have been referred to, because they 
 not only are commonly known, but also are among the most im- 
 portant. The importance of the mineral content has been conclu- 
 sively shown already in the several connections, so that no new 
 space need be devoted to the subject. 
 

 III. OBSERVATIONS ON ROCKS 
 
 1. Quarry. From the quarry one learns the color of a rock, 
 or its colors, as the case may be, its hardness, structure, weight, 
 and something about its texture. Also, the main minerals, m&y 
 be determined with the resistance they offer, severally and col- 
 lectively, to the atmospheric agents of dcomposition. The ability 
 of a rock to temper well, the colors of the rough and tpolished 
 surfaces, with much about the larger features, can be ascertained. 
 The weathering effects often show important things. All incip- 
 ient joint planes, all lines of weakness, all traces of lamination, 
 which are not noticed in the fresh stone, are brought to light in 
 the slightly altered portions. Changes in color are caused in like 
 manner, due both to bleaching, and to staining by the decompo- 
 sition of particular minerals. Lastly, the quarry shows unmistak- 
 ably the average character of the rock and not alone its best 
 specimens, and the amount possible to expect for commercial 
 purposes. Quarrying in some of its details, is much like mining 
 The owner almost invariably selects the best piece of rock to be 
 found to exhibit and who can blame him with the result that 
 often totally erroneous ideas may be conceived and ultimate in- 
 jury done to a good business proposition. 
 
 2. Buildings. This is an important means of determining 
 the value of a given material. It is not, however, as some think, 
 the best or only means, A stone which has proved a failure in 
 one building may owe its poor showing not to inherent weakness, 
 but to a number of various causes, of wjiich the most common 
 are the improper working of the rock preparatory to laying, and 
 the lack of consideration regarding the qualities demanded by the 
 structure. The permanence of color and temper, the power to 
 withstand the attacks of the wind and dust, the effect of sustained 
 load, in a word the permanence of the material, may be largely 
 ascertained by these observations. In such estimations it is to 
 be borne in mind that many things must be regarded as influenc- 
 ing deterioration. For instance, some buildings are more exposed 
 than others to all sorts of active agients, as tine acids in manu- 
 facturing districts. And in every case there are multitudinous lit- 
 tle details which every fair minded observer should notice. No 
 stone should be condemned because of one or two failures, as in 
 this way a blow is dealt an important industry. 
 
 3. Chemical. Since the decomposition of any building ma- 
 terial is strictly a chemical process, a knowledge of its chemical 
 constituents, and hence properties, is necessary if we would thor- 
 
oughly understand it's fitness for use. In investigating this qual- 
 ity of a stone we need simply to apply chemical principles to thje 
 determined composition in order to throw light on possible alter- 
 ation. For a simple examiple, a sandstone ninety-six per cent, 
 silica is obviously far more servicable than one containing fifteen 
 per cent, of lime. A type analysis will be found under granites 
 in chapter IV. 
 
 4. Physical Tests. These are of several kinds, all of funda- 
 mental importance, and serve to fill out the knowledge gained by 
 the methods already mentiond. 
 
 a. The strength of a stone is measured directly in a testing 
 machine by applying force to carefully cut blocks. Commonly 
 two inch cubes are crushed, the figures obtained being corrected 
 to ultimate crushing strength per square inch of surface. The 
 machines used are those employed in the testing of strengths of 
 materials in engineering laboratories. The Nevada State Uni- 
 versity is not yet equipped with such apparatus, which is one of 
 the main reasons for the incompleteness of the report. Such 
 a machine, with a limit of 200,000 pounds pressure costs in the 
 neighborhood of $10,000. The transverse strength is tested by 
 using a suitable prism of stone, laid crosswise on supports. 
 
 b. The specific gravity of a stone is the ratio of its weight to 
 the weight of an equal volume of water. The common term 
 ''weight" is used in practice, and is similar but not the same, as 
 ' 'specific gravity." For instance, a cubic foot of water weighs 
 about 63 pounds, and its specific gravity is, of course, I (one) 
 The specific gravity of a granite, let be assumed, is 2.65. Hence 
 its weight per cubic foot, were it absolutely solid, would be 
 63x2.65, or about 225 pounds. As a matter of fact, the porousity, 
 or air space, reduces this figure, which would be about 175 pounds 
 weight. To obtain this figure, a simple and fairly accurate meth- 
 od is as follows. A representative piece of the rock to be tested 
 is obtained, say containing about four cubic inches. This is thor- 
 oughly cleaned of all loose particles, dried at no deg. Centigrade, 
 and carefully weighed in air. It is then suspended by a hair in 
 boiling distilled water for at least an hour, and after cooling to 
 the temperature of the air it is weighed in the water. The dif- 
 ference in the two weights gives the weight of an equal volume of 
 water, which, divided into the dry weight of the stone, gives its 
 specific gravity. The boiling is to drive out all enclosed air which 
 is never done completely, so that the results are a little low, yet 
 are satisfactory for the most practical neels. Also the boiling tends 
 
to loosen any small fragments not removed, which also lowers 
 the result. The most accurate way is to place the stone in -the wa- 
 ter under the receiver of an air pump and exhaust the air. This 
 can be done in the more complete laboratories. This state- 
 ment is to be remembered : the weight of a rock is proportional 
 to the specific gravity, porousity, and water content. 
 
 c. The porousity of a stone is obtained in the above measure- 
 ment by weighing the piece thoroughly saturated with water im- 
 mediately on its removal from the water in which it was suspend- 
 ed. This gives the weight of the dry stope plus the weight of 
 water absorbed in the pores of the substance. What is desired, 
 the porousity, is the ratio of the open space in a rock to its total vol- 
 ume. To obtain this we divide the weight of a piece by the weight 
 of the same material which would just fill the open places. The 
 first weight of the dry stone is already known, and we obtain the 
 second by multiplying the weight of water absorbed by the spe- 
 cific gravity of the whole. The great importance of this figure has 
 already been pointed out, particularly in regions of great temper- 
 ature variations and considerable moisture. A stone thoroughly 
 seasoned, however, ordinarily suffers little. 
 
 d. The effects of freezing and thawing on a stone, both dry 
 and saturated with water are properly tested under those condi- 
 tions most nearly coinciding with those actually encountered. A 
 cube of the rock may be exposed, both dry and wet, to the chang- 
 ing temperature of day and night during the winter, for a period 
 of at least a month, and then tested for loss in weight and strength. 
 The action of extreme heat, as in the case of fire, may be tested 
 by heating a fragment to redness in an assay muffle, and noting 
 the effect, first, on cooling slowly and second, on plunging the hot 
 stone into cold water. The loss in strength is tested in the usual 
 way. 
 
 e. Lastly, but not least important, much light can be thrown 
 on all the above qualities of a building material by examination 
 under a microscope. Sections of the rock are ground to a thick- 
 ne&s of about two hundredths of a millimeter, and mounted on 
 glass slides. An examination under a propery designed micro- 
 scope shows everything about the minerals : their relative abun- 
 dance, nature, size, and mutual relations. Also, texture and 
 even structure missed in all the other methods of investigation, 
 may be shown in this way. Yet the life of the stone might de- 
 pend upon these very things. In short, a microscopic examina- 
 tion puts the finishing touches upon a thorough search after the 
 
qualities of a building material, and such a search is incomplete 
 without this investigation. 
 
CHAPTER IV 
 
 BUILDING STONES OF NEVADA 
 
 In actual amount, Nevada is well supplied with rocks which 
 can be used as building material. At present, with a territory only 
 beginning its true development, comparatively little is used, and 
 few quarries are opened. Were the following list taken only from 
 those actually quarried, a poor showing would be made. It has 
 been the aim to include also those rocks which can easily be made 
 use of at a profit, in order that both capital and attention may be 
 attracted. All throughout the west, a region of first class building 
 stones, the fact remains that the value of imported stone runs 
 annually into the hundreds of thousands of dollars. The reason 
 seems to be that people refuse to take advantage of natural op- 
 portunities and to develop their own resources, largely because 
 imported material is easy to obtain and is less common than home 
 products. It is true that the commoner uses of stone, as curbing, 
 abutments and some buildings, are supplied by materials produced 
 here, but for the finer uses a very large percentage of imported 
 stone is placed. The west suffers from a lack of red granite for 
 ornamental work, as in monuments, yet there is, some first class 
 rock of this color both in Nevada and California which should 
 be developed. At the present writing, nothing can be given in the 
 way of figures of invested capital, costs of handling stone, wages, 
 et cetera, for the simple reason that they are not obtainable. Not 
 one quarry in the state is working, and except when a lot of stone 
 is needed for some sudden purpose, no work is ever done. Need- 
 less to say, the capital invested is at the most but a few hundred 
 dollars, outside the value of the land, hence is not important. The 
 location and the possibilities of building stones are the most val- 
 uable part of what follows. Much in this chapter will be of no 
 immediate value; much will be fragmentary, for it is difficult to 
 obtain accurate data throughout. Many of the important qualities 
 of a stone can be determined only after a quarry face has been 
 opened, and as yet the University is not equipped with a testing 
 machine, hence it will be some years before a detailed report can 
 be published. 
 
 The rocks will be mentioned in the order given in the classi- 
 fication in chapter II, beginning with the plutonic igneous, or, as 
 they are sometimes called, the "granitic rocks." 
 
 PLUTONIC OR GRANITIC ROCKS 
 
 Under this division there are several important stones actu- 
 
ally in use, and others with first class possibilities. And in class- 
 ifying these rocks a slight difficulty is presented. Such rocks are 
 called popularly granites. Some of them are granites ; others are 
 not, but all are related. The geographical belt lying on the east 
 flank of the Sierra Nevada and along the foothills is characterized 
 by an abundant development of these, all more or less connected 
 in origin, yet varying from those properly termed granites to 
 those of dioritic nature. As a group, chemically they stand be- 
 tween these two types of plutonics, containing an excess of soda 
 over potash, and often considerable lime. Some contain an abun- 
 dance of free quartz, others show little to none. As any petro- 
 graphical discussion is here out of place, only a few remarks of 
 this nature will be presented under each rock. The writer hopes 
 to show later, in a petrographical paper, the true relationships of 
 the granitic rocks of this western portion of Nevada. For the 
 present, the term granite will be used exclusively for those rocks 
 showing free quartz. 
 
 GRANITES. 
 
 Laughtons Station : This stone occurs in the immediate 
 vicinity of Laughton's Station, to the north of the Southern Pa- 
 cific Railroad track, about five miles west of Reno. Considerable 
 amounts of rough stone have been taken out at the outcrop di- 
 rectly on the railroad, but no real quarry face has been opened. 
 In color this granite is a medium to light gray, with occasional 
 splotches of a darker shade. The rock is abie to take a good pol- 
 ish, quite in contrast to the rough finish. Considerable joint 
 structure is developed on a large scale, sufficient to make quarry- 
 ing easy, and yet not enough to preclude the possibility of extract- 
 ing large blocks. The texture is of medium fineness, or grain, 
 in the main phase of the stone, but varies considerably. The nor- 
 mal rock has much more white mineral than dark, but often 
 rounded spots occur which contain a much larger percentage of 
 black constituents. These spots are at times thickly interspersed 
 throughout the main mass ; often they are seen as isolated dark 
 centers surrounded by many feet of surface of the normal 
 variety. The minerals to be seen by the naked eye are quartz/ 
 feldspar both orthoclase, the potash variety, and plagioclase, the 
 .soda-lime variety, brown mica, and black hornblende. The mica 
 is the chief dark mineral in the normal rock, but hornblende pre- 
 ponderates in the dark spots. Under the microscope the orthoclase 
 felspar is seen to be in crystals much larger than those of the oth- 
 er minerals, and is also greater in amount than the plagioclase. 
 
The quartz is not in great percentage. Little or no pyrite is pres- 
 ent. As in all granite, die hardness is considerable. The rock 
 is rather brittle, and the crushing strength is medium for a gran- 
 ite, the variation in grain lowering this value. The stone, because 
 of its location on the railroad, is available at once and in large 
 amount. The railroad owns that part of the massi now quarried 
 at all, and can furnish vast quantities when required. Unless a 
 well opened quarry should show a more uniform grade of mater- 
 ial, the uses of the stone will be limited. It can be used for orna- 
 mental work if no variations in texture are present, and for all 
 the more common demands, such as foundations, curbing, walks 
 and the like it will give satisfaction. 
 
 Verdi : In the vicinity of the town of Verdi, which is about 
 ten miles west of Reno on the Southern Pacific railroad, consid- 
 erable areas of granite exist. Much of it is directly on the rail- 
 road, south of the town, along the Truckee river. From Verdi to 
 the south the surface rises steeply for about two hundred feet 
 to a level terrace of granite, with boulders of andesite disjpersed 
 over it, the last remains of an extensive flow. Several faults oc- 
 cur on this terrace, with resultant rise of the plutonic rock and 
 increased opportunity for quarrying. No quarrying has yet been 
 done, but the possibilities are surely worth serious consideration. 
 There are two types of granite which will be described. 
 
 i. This first type of rock is that which makes up most of the 
 mass. The color is a rich dark gray, with a faint trace of pink, 
 giving as a result a very handsome stone. It is able to assume a 
 high polish, showing quite dark in comparison with the rough 
 surface. As no quarry face has been opened, nothing can be 
 stated about the structure of the rock, except that as some fault- 
 ing has occurred, joint planes are probably developed. From the 
 outcrops existing, the texture appears fairly constant, there being 
 a slight change in color in widely separate localities. However, 
 the stone seems to be remarkably free from imperfections in this 
 respect. The minerals present are quartz, feldspar, mostly ortho- 
 clase, hornblende, and mica. The hornblende is the more plentiful 
 of the dark constituents. The pinkish tint is due to the color of 
 the orthoclase, which is a pleasing flesh color. Quartz is not very 
 plentiful, whereas the black minerals are, hence the dark color of 
 the whole. The sulphides are very small in amount. The hard- 
 ness and toughness are perhaps a little higher than in the Laugh- 
 ton stone, and sufficient for all purposes. But like the Laughton 
 stone, it is so situated that it is available at any time with lowest 
 
possible cost of handling. An opening to exhibit the character of 
 the mass is all that is needed to show it up properly. For monu- 
 mental work as well as for all the best uses, this granite should 
 find a ready market, if present indications have much weight. 
 
 2. The second variety of granite from Verdi is found at 
 present only in boulders lying on the worn surface of the other. 
 It undoubtedly occurs as veins in the main mass, and should 
 properly be called a pegmatite. These dykes must be of large size, 
 because of the dimensions of the largest fragmens derived from 
 them. A quarry is necessary to outline any facts about the mat- 
 ter. The color is either a light red ground through which are 
 irregularly dispersed black shining crystals of tourmaline, or 
 more rarely, a white ground with the dark mineral. The general 
 effect is very pleasing to the eye, presenting a sharp contrast to 
 the other variety of granite. The texture is peculiar, for the min- 
 erals are not at all regularly distributed. The mass of the rock 
 is made up of quartz and feldspar, usually redish orthoclase, 
 through which occur bunches of black tourmaline crystals. The 
 quartz and feldspar are of fine grain, while the black mineral, in 
 coarser crystals, is in spots in size from a quarter of an inch up 
 to a foot or more. The stone will take a high polish, differing 
 little from the unfinished surface in shade. It should meet with 
 favor for some kinds of ornamental work, as well as for building 
 material, if it can be obtained in large enough amount. 
 
 Washoe: This ganite outcrops west of the old town of 
 Washoe, on the Virginia and Truckee railroad, and is a part of 
 the great granite mass occurring at the east base of the Sierra. A 
 quarry is opened about a mile west of the town, on land owned by 
 Mr. John Barrett, the stone cutter of Reno. Not a great deal of 
 work has been done, yet the stone has been shown to be of fairly 
 uniform color and grain. The color is a medium dark gray, with 
 a very faint pinkish tinge, lighter than the Verdi rock. There ap- 
 pear to be few or no imperfections in structure debarring the ex- 
 traction of large pieces for use, but, in common with most of these 
 rocks of the region, the texture varies somewhat. At times 
 splotches of dark constituents occur to mar the even aspect of the 
 surface. Careful selection, however, should eliminate this evil. 
 A good polish is taken, quite dark compared with the unfinished 
 stone. The minerals are quartz, both varieties of feldspar, mica 
 and hornblende. The two dark constituents are about equal in 
 amount while the quartz is sparingly distributed. The sulphide 
 minerals are rare, as in all of these rocks. Both hardness and 
 
toughness are fairly high, and should improve as deeper cuts are 
 made in the quarry. This stone is not quite so readily available as 
 those already mentioned, as a haul of a mite to the railroad is 
 necessary. At present the granite is used for monuments and 
 ornamental purposes by Mr. Barrett. 
 
 Nearer the railroad, and| in fact, directly on it, is an occur- 
 rence of volcanic and plutonic boulders, in which are some of 
 granite. This stone is the same as the Washoe granite just men- 
 tioned, and is quarried by the railroad for use in culverts, abut- 
 ments, and the like. Such a source is, necessarily, limited in ex- 
 tent, yet it does sufficiently well for immediate needs. And it may 
 be well to note here that most of the granite now used in and about 
 Reno for curbing, mounting blocks, and such commoner demands, 
 is obtained from the vast quantity of boulders existing in the 
 river wash covering much of the adjacent territory. It is needless 
 to remark upon the cheapness of this source, yet the best quality 
 of material cannot be furnished in such a way, so that the ultimate 
 cheapness is lessened. Only a well opened quarry will deliver 
 the best stone, and when substantial, long-lived buildings are to be 
 constructed, field boulders should never be used unless of excep- 
 tional size. 
 
 Ophir: This rock is well exposed at Ophir, about a mile 
 northwest of Franktown, on the Virginia and Tnickee railroad. 
 A little preliminary quarrying has been done at a point just south 
 of the wood flume, on the small creek here draining down from the 
 mountains. The stone rises up about a hundred feet above the 
 creek, giving some opportunity for working. As yet the solid mass 
 of the granite has not been reached, the quarrying has been done in 
 the more or less broken surface material. The color is the lightest 
 of all those described being, in the average, a very light gray. 
 Some varieties, small in amount, are darker in shade. A good 
 polish is possible, which is little darker than the rough surface. 
 Jointing is well developed, insuring ease in quarry work while 
 not preventing the extraction of large blocks. In texture the rock- 
 as a whole varies considerably, though the main mass is fairly 
 constant. Normally the crystals of the component minerals are 
 fine in grain, with longer black crystals sparingly distributed 
 throughout. The minerals of fine even grain are quartz, both 
 feldspar and brown-black mica, the larger black crystals are horn- 
 blende. The quartz is very plentiful, giving almost a glassy luster 
 to the rock. Also, many small grains of a yellowish mineral are 
 dispersed rather plentifully. The other varieties are due to the 
 
change in the relative amounts and kinds of the minerals present. 
 Some show an abundance of large shining mica flakes with little 
 or no hornblende ; some show much hornblende with no mica ; and 
 others show a great amount of clear colorless quartz. These, how- 
 ever, are in small amount. This granite is very hard, but more 
 brittle than the others. It's availability is apparent, being less than 
 a mile from the railroad. It's possible uses are limited by it's vari- 
 ation in texture to the commoner ones, such as curbings, mount- 
 ing blocks, foundations, and pavements, though it's light color 
 might find favor for contrast in monumental work. 
 
 Lakczncw: This stone is well shown in the railroad cuts 
 south of the station of Lakeview, three miles northwest of Carson 
 on the Virginia and Truckee railroad. The railroad grade winds 
 around a hill composed chiefly of this rock, thus making it pos- 
 sible to obtain vast quantities at a minimum cost. Xo quarrying 
 of any sort has been done, as the stone is' not of the best quality 
 for building needs. The color is a light gray, similar to, but 
 darker than the Ophir granite. In the exposed outcrop many lit- 
 tle dots of red are to be seen on careful inspection. The mass 
 of the rock is quite faulted and jointed, but blocks of large size can 
 be taken out, judging by the weathered portion. The texture is 
 rather coarse in appearance, because of the large size of the horn- 
 blende crystals ; the light colored constituents are of finer grain. 
 The minerals are quartz, feldspar, again both kinds, with a slightly 
 larger percentage of othoclase, hornblende and mica. The horn- 
 blende is the chief dark constituent. Quartz in nominal amount. 
 A considerable number of small grains of a yellowish mineral 
 are present, as in the Ophir stone. One other substance is worthy 
 of notice ; the mineral magnetite, which shows quite plentiful under 
 the microscope. Such a rock as this is limited in usefulness to 
 the commoner demands, and it is also possible, on account of the 
 mineral content, to use it as a road metal. It's vast amount, easy 
 or" access, its small mica percentage and its comparatively large 
 percentage of iron, make it easily possible that it might prove a 
 success as a material for macadamized roads. 
 
 Carson Prison : On the Prison Hill as it is called, a granite 
 similar, or the same, outcrops from beneath the andesite flows. 
 This locality is not on the line of the railroad, but is easily ap- 
 proached by teams. If the stone proves a good road metal, this 
 would make a good locality to furnish material for those parts of 
 the region nearby. 
 
 : Near the town of Liming, in Esmeralda county 
 
and five miles from the line of the Carson and Colorado railroad, 
 there is an occurrence of a fine grained white granite. No reai 
 quarrying has been done, and only a small amount of stone has 
 been extracted. Small pieces show a finer grain than in the other 
 granites described, and exhibit a contrast with them. The land 
 and stone is owned by Mr. Lindsay, of Carson, who has the stone 
 for sale, as well as for his own use in building work. 
 
 Mason Valley : This stone occurs near Mason Valley, in 
 Hudson Pass, Lyon county, about eighteen miles from the Car- 
 son and Colorado railroad. As with most of the other rocks, no 
 quarrying of any amount has been done, ami the stone awaits a 
 market. The color is rather striking, being a light mottled pink- 
 gray. On close inspection three distinct colors present themselves, 
 due to the different minerals ; white, pink and dark green. The 
 polished surface brings these out well, and presents a considerable 
 and pleasing contrast with the rough finish. The grain is medium 
 and even, with an occasional large white crystal. The polish 
 brings out clearly most of the component minerals. To the 
 naked eye no quartz is present, and the rock looks like a syenite, 
 or that rare rock standing between a syenite and a diorite a 
 monzonite. The minerals easily seen are feldspar, including 
 stout pink crystals of orthoclase, and long white crystals of plag- 
 ioclase. Under the microscope, quartz is apparent, making the 
 rock a granite though a basic one. Both hardness and toughness 
 are high. The stone is not as available as could be desired, yet its 
 color and other qualities are such that its value is high. It can 
 be used for monumental work, and buildings, and should find i 
 ready market. The owner of the present "quarry" is Mr. Lindsay, 
 of Carson. 
 
 Winncmncca: Two varieties of granite are used in Winne- 
 mucca. The first is quarried twelve miles to the north of the town, 
 and hauled in by teams. It is a medium light gray stone, taking 
 a fine polish, and is sufficiently good for the best class of work. 
 The grain is of medium coarseness, with little variation in color 
 or mineral content. The minerals are the usual ones already men- 
 tioned, with not a great deal of quartz. By way of illustrating 
 availability, some figures of cost of hauling for this stone will be 
 .given, which are fairly good for others removed from the railroads. 
 A trip from Winnemucca to the quarry and return occupies two 
 days, with a large wagon. Seventy-five cubic feet of stone are 
 hauled at a trip, for which eighteen dollars are charged. This 
 stone has found some favor for monuments in the town, and can 
 
be used for ornamental and construction work. Mr. Joe Pasquale 
 is owner. 
 
 The second granite used in Winnemucca is taken from boul- 
 ders found on the lower slopes of the mountain bearing the same 
 name as the town. In color and general appearance it is much 
 like the first, but takes a poorer polish. It also has found some 
 demand for monuments and buildings, but is inferior to the first 
 because of longer exposure in fragments. However, it is, well 
 adapted to all the commoner uses. 
 
 Elko : Much granite exists both to north and south of the 
 town of Elko but at some distance. At present one variety is 
 quarried, and used in the town for nearly all purposes. This rock 
 comes from a spot about thirty miles north, necessitating a long 
 haul. The distance from the railroad limits its use and market, 
 for when a quarry is well opened on the line of the railroad, as can 
 be easily done, at a place like Verdi, such a stone will be driven 
 from use by it's cheaper rivals. It is possible to find some first- 
 class monumental granites in the region about Elko. And there 
 are many other possible stones. Granite is plentiful at Steamboat 
 Springs, and more at Verai, up Dog Creek Canyon. Likewise 
 in the eastern part of the state there is much similar stone, most 
 of it unknown in value and qualities. But for some years only 
 the most valuable granites existing away from transportational 
 facilities can be available, because of the wealth of easily obtained 
 poorer stone outcropping directly on the railroad lines. 
 
 DIORITES 
 
 Virginia City : The mass of Mt. Davidson, upon whoste 
 eastern flanks Virginia City lies, is chiefly of a dioritic rock. It is 
 not urged that this rock would make a first-class building material, 
 for it's color is a somber gray, it's grain fine, and the whole aspect 
 uninviting. It is mentioned in tnis place because of its possible 
 use as a road metal. It's constituents are feldspar and hornblende, 
 with usually some iron pyrite. The texture is one of interlocking 
 crystals, causing very great toughness. There are several phases 
 of the stone, each with it's own color and general appearance. 
 The summit outcrop develops a gray granite looking rock; the 
 tunnels and crosscuts in the mines often show a much darker va- 
 riety. For a road metal, the binding power should be good, while 
 the toughness will be vouched for by every miner who has driven 
 a drill into it. As mentioned in the chapter on road metal, the 
 rock may prove easily a most valuable one for use on roads under- 
 lying heavy traffic. 
 
Ill 
 
 Beckwith Pass: This rock is found near Beckwith Pass, i 
 California, but as its development must come through Nevada, it 
 is here included. Like all the granite rocks, it exists in practi- 
 cally unlimited quantity. A little quarrying has been done, suf- 
 ficient to show up the stone fairly well. The color is a very dark 
 gray, darker than the Verdi granite, which it somewhat resembles 
 in appearance. It takes a perfect polish, which does not present 
 a great contrast to the rough surface, as the stone is essentially so 
 dark. The grain is of medium coarseness, and very constant; 
 the stone is quite free from irregularities of all sorts. The min- 
 erals present are plagioclase feldspar, with mica and hornblende 
 in nearly equal amount. Black magnetite also occurs. The hard- 
 ness and toughness are fairly high. It is yet necessary to haul 
 the stone some distance to the railroad, which militates slightly 
 against it's use. With the advent of the proposed Western Pa- 
 cific railroad, this difficulty will be largely eliminated. The quar- 
 ry now operated is owned by Mr. John Barrett, of Reno, who has 
 been mentioned as owning a Washoe stone. This diorite is now 
 used for monumental work entirely, and is well fitted for all the 
 best class of uses. It also might prove a valuable road material, 
 for which the chippings and waste could find a market. 
 
 VOLCANIC ROCKS 
 
 RHYOUTUS 
 
 There are two stones used in Nevada which are classed with 
 this group of rocks. Both are from the region just south of Vir- 
 ginia City, near the American Flat Tunnel on the line of the Vir- 
 ginia and Truckee railroad, in Lyon county. Both are quartz- 
 porphyrites in a general sense, though there are variations from 
 a true quartz-porphyry or rhyolite, to a quartz-andesite, or dacite, 
 based on the nature of the included feldspars. In detail these 
 rocks are as follows : 
 
 i. The first stone is quarried from the great mass covering 
 many acres, at a point on the railroad one- fourth of a mile west of 
 the American Flat tunnel. The color is a not unpleasant yellow- 
 ish white, a suitable shade for a dry, dusty climate. The texture 
 is porphyritic, and even throughout large volumes. On close in- 
 spection the color is seen to be due to the ground mass ; while the 
 crystals showing are chiefly clear quartz, and white feldspar. 
 Some small grains of iron bearing minerals, as mica, are present 
 in small amounts. The general effect is good, a little different 
 from the usual run of stones. The rather large glassy quartz 
 grains, particularly, give the rock a distinct individuality. The 
 
hardness is high; the toughness a little less, and both rank with 
 the best. Much resistance to atmospheric changes is given, so that 
 long life to a structure of this material is assured. The quarry 
 cut is directly on the railroad, so that any amount needed can be 
 easily obtained, the railroad, of course, owning the land. This 
 stone was much used in the early days on the Comstock, chiefly 
 for foundations. It shows no evidence of change where so used. 
 The railroad now constructs of it abutments, culverts, retaining 
 \valls and other similar structures. 
 
 2. The second quartz-porphyry is quarried five-eights of a 
 mile east of the tunnel already mentioned. The color in the mass 
 is a medium dark purplish, which color is a not inconsiderable 
 factor in the worth of the stone. The texture like that of the 
 other, is porphyritic, with well developed crystals of quartz, feld- 
 spar, and dark mica. The color is due to the purplish-gray ground 
 mass, in which the other minerals show distinctly. The main 
 difference between these two rocks is in the color, and the increase 
 In the amount of mica in the purplish variety. This latter stone is 
 decidedly pleasing to look upon, and should find favor for build- 
 ings. It's hardness, toughness, and other characteristics are 
 identical with those of the first of these rocks, and likewise it is 
 quarried by the railroad and used in some of it's culverts and 
 abutments. It has been used in one of the railroad crossings at 
 Steamboat Springs, and makes a fine appearance. 
 
 ANDESITES 
 
 There are several quite prominent building stones under this 
 rock group, including some of great promise. As the demand for 
 such materials of construction increases, they should all find ready 
 markets, particularly as they are easy of access and near the cen- 
 ters of population. 
 
 Southwest of Row: This stone is the one used largely in 
 die erection of the new Carnegie Library Building in Reno. It is 
 locally called a sandstone. It comes from one of the large andesite 
 flows which bathed the lower eastern flanks of the Sierra in recent 
 geological time. The quarry is situated at a 'point about four 
 miles southwest of Reno in an air line, though nearly two miles 
 further by road. The work here has just begun, and is due to 
 the construction of the building just mentioned. Enough has been 
 accomplished, however, to show some of the larger characteristics. 
 The quarry shows well the flow structure of the mass ; the planes 
 of motion lie nearly horizontal, greatly facilitating the extraction 
 of large blocks. On this account, the cost of quarrying is very 
 
low, aided also by the absence of any overburden, or surface waste 
 material, beside a few feet of rocky soil. The color is a medium 
 light red or red-gray, similar to but redder than the tint of the 
 quartz-porphyry from Virginia City. The texture is porphyritic, 
 showing white feldspar crystals with smaller ones of mica and 
 hornblende, in the red-gray ground mass. The white feldspar is 
 all that shows on a cursory examination, and as much of this min- 
 eral is present, the popular term sandstone has been employed. 
 These more or less lath shaped crystals of feldspar are arranged 
 roughly parallel along the flow planes. The red color of the 
 ground mass owes it's nature to the decomposition of the iron* 
 bearing ground mass, with the resultant deposition of iron oxide 
 throughout. The effect produced is fair to look upon, but the 
 stone is weakened thereby. The hardness and toughness are low 
 for a rock of this type, and are little better than in .an average 
 sandstone. It would crush, probably, at a pressure of about six 
 thousand pounds per square inch. This is sufficient for all or- 
 dinary demands, but not enough for the very largest buildings 
 now erected. It will withstand much in the nature of temperature 
 changes, as will all the rocks of this group. 
 
 Being situated near Reno, it should be used in many more 
 buildings to be erected in the near future. It's general appearance 
 counts strongly in it's favor. 
 
 On the western side of the ridge on which the above quarry 
 is situated, is a second outcrop of the same rock. There is a dif- 
 ference, however, for here the red color is replaced by a gray, due 
 to the non-oxidation of the mass. The other features are the 
 same, except that the lasting qualities are much better. The two 
 stones are in pleasing contrast, and will undoubtedly find favor in 
 a short time. 
 
 Huf faker: There are two varieties of andesite at this point, 
 five miles south of Reno on the Virginia and Truckee railroad. 
 The railroad here skirts the foot of a rather low hill, on which out- 
 crop the rocks in question. They are both part of the same mass. 
 
 The first is a red stone, a shade darker than the library ande- 
 site. It forms most of the surface material and can be obtained 
 in quite large amount. No quarry face has been opend, so that 
 nothing can be told about is structure. It has no flow planes like 
 the first mentioned andesite. It is porphyritic in texture, showing 
 well formed crystals of black hornblende, red 'discolored lath 
 shaped crystals of feldspar, and all in the red ground mass. The 
 hornblende is quite plentiful, the feldspar is about equal in amount, 
 but decomposed and reddened as is the ground mass. The hard- 
 
ness is medium, the toughness somewhat less. The availability 
 of the material is a strong point in it's favor, as it outcrops less 
 than a hundred feet from the railroad track. It is on the Huffa- 
 ker ranch, and has been used locally to some extent. 
 
 The second variety is a granitic looking rock, and by the av- 
 erage individual would possibly be called a granite. It outcrops 
 on the same hill as the other, and, due to the fact that less decom- 
 position has taken place, lacks a red color. It is a medium light 
 gray stone, apparently showing quartz, feldspar, and hornblende. 
 Careful study, with and without the microscope, show it to DC 
 a truly prophyritic rock, of medium grain and even texture. The 
 minerals in well formed crystals are white feldspar, black horn- 
 blende, and a few flakes of mica, set in a glassy, colorless, ground 
 'mass. It is this glass which has the appearance of quartz. The 
 general aspect of the rock is decidedly in its favor. As no real 
 quarrying has been done, and no thoroughly unaltered rock ex- 
 posed, it's other qualities are not known. From it's construction 
 it must be a very hard though perhaps brittle, stone. The Huffa- 
 ker residence, a large two story structure, is made of this material, 
 which shows no change in its thirty years of service. These two 
 andesites are worthy of careful investigation and some work done 
 to exploit them. 
 
 Pulton's Quarry: The rock exposed in this place exists to 
 the north of Reno, over considerable territory. The quarry itself, 
 in the best material, is about two miles north of the University 
 campus, just above the line of the Nevada, California and Oregon 
 railroad. What work has been done is all on the surface; no 
 quarry face has been well opened. The color is a light greenish 
 gray in the mass, and a restful one to the eyes, especially in the 
 glare of the sunlight in a hot, dry climate. The rock is rather 
 strikingly porphyritic on close inspection, though of even appear- 
 ance at a little distance. Large glassy feldspar crystals half an 
 inch in length are frequent. Also, many flakes of dark mica are 
 present, with a little hornblende, and all set in the compact, green- 
 ish-gray ground mass. In selected pieces the texture is fairly con- 
 stant, but as a mass much variation occurs. Inclusions of other 
 materials are found, and small cavities lined with materials are 
 at times plentiful, so that careless work may result in unsightly 
 spots in buildings. The hardness and toughness are fair, and the 
 resistance to weather changes is good. As it is on the railroad, 
 it's availability is excellent, and there is a vast quantity in sight. 
 The stone has been used considerably in Reno. Several of the 
 newer University buildings contain it, as the gymnasium and 
 
Lincoln Hall, and a few structures in the business part of town are 
 made wholly, or nearly so, of the material. It's greenish tinge 
 gives a pleasing aspect to the buildings containing it. Another 
 possible use is that of road metal. In the search for such mater- 
 ial soon to come, a test upon the rock would not be ill advised. 
 
 Virginia City : About two miles to the east of the old town of 
 Virginia City runs a ridge approximately north and south. Sugar 
 Loaf peak is part of this ridge, which is cut in two by Six Mile 
 Canyon and Creek. An andesitic rock forms this feature of the 
 topography, furnishing one, and able to furnish two, stones for 
 building purposes. 
 
 The first of these is quarried at a point just east of the Bruns- 
 wick Lode, on the east side of a small hill rising from the ridge. 
 Considerable rock has been taken out here, yet in a more or less 
 careless manner, and no well cut face is shown. The structure of 
 the mass is quite remarkable. Rock columns averaging two feet 
 or more in diameter compose the whole, like a bundle of sticks 
 laid carefully parallel to one another. These columns pitch to the 
 northwest at a low angle, aiding very materially the quarrying 1 . 
 This stone is the most striking in appearance of all those describ- 
 ed in these notes, and is almost beautiful. Any one word will fail 
 properly to give the color, for the texture his given the rock a 
 mottled aspect. This texture is porphyritic, and large roughly 
 rounded feldspar crystals often half an inch across, with smaller 
 prisms of hornblende and flakes of dark mica appear in a blue- 
 gray, or steel blue ground mass. The feldspar is quite glassy, 
 much in contrast to the lusterless colored ground. There is some 
 variation in texture, which must be guarded against by selecting 
 only the best. Frequently small inclusions with slightly differ- 
 ent color and grain occur, which spoil the even effect of the whole. 
 The hardness, toughness, and other characteristics are good, and 
 need little consideration under ordinary circumstances. The stone 
 is easily obtained, the quarry being less than two miles from the 
 railroad, and an easy haul will deliver it at the station. It was 
 used extensively in the early days of the town for foundations for 
 large machinery. As it yet remains in place, one can see how well 
 it stands. To state that it makes a beautiful appearance does not 
 seem like exaggeration. 
 
 The second variety of these andesites occurs in Sugar Loaf, 
 and in the exposed places in the immediate vicinity. It has not 
 yet been quarried nor used. A fine exposure is present to the 
 southwest of the road in Six Mile Canyon just where the bridge 
 spans the creek at the base of Sugar Loaf. This rock is very 
 
similar to the first, yet distinct in its general appearance. The 
 ground mass is a very light gray, with a faint tinge of blue, and 
 the well formed minerals are white feldspar, in smaller crystals 
 than in the first phase, with black hornblende more plentiful than 
 before, and a little dark mica. The other qualities are about the 
 same as those of the first variety, and are good. A little harder 
 pull by team is required to land it at the railroad yards, yet this 
 will not count much against it. As far as known, this stone has 
 never been worked, but it would make a very good building mater- 
 ial. 
 
 TUFFS 
 
 There are three of these valuable building stones now in use 
 in the state. They are softer than the average consolidated tuff, 
 yet this lack does not prevent their being used in many important 
 ways. They fill a want for certain kinds of materials better than 
 any other stone, and at times rank with the best sandstones. 
 
 Mcrrimac Station : This tuff outcrops in the Virginia 
 Range in the canyon of the Carson river, at Merrimac Station, 
 on the line of the Virginia and Truckee railroad. This point is a 
 few miles east of Empire, and v within easy reach of all important 
 points. The quarry, owned by Mr. J. W. Adams, of Carson, is on 
 the south bank of the river, and is one of the very few well opened 
 ones in Nevada. The color of the stone is a light pink, almost a 
 flesh color, and does not vary throughout the mass. As it is com- 
 posed of volcanic ashes, with some mineral fragments, it's texture 
 might be taken to indicate a very fine grained sandstone. The 
 fragmental character is clearly shown, and the absence of strati- 
 fication planes or layers indicates to the unaided eye the nature of 
 the material. The ash is largely glass, in minute fragments', 
 in which are imbedded angular pieces of mica, quartz, and feld- 
 spar in small amount. The grain is very even for such a stone, 
 and it's general effect is very good. In hardness and toughness 
 it stands low, about equal to a soft sandstone, too low to warrant 
 it's use under much stress. It tempers a little on standing, but 
 not sufficient to raise much it's strength. It is rather porous, as 
 are all the tuffs, yet withstanding temperature changes well, be- 
 cause of it's internal structure. It has been used very largely in 
 and about Carson and Reno, chiefly for copings, cornices, lintels, 
 arches, and such others requiring little strength. When used with 
 brick, a very pleasing contrast is presented, as is done with any 
 other material harmonizing with it in color. The Gymnasium 
 and Lincoln Hall of the University Buildings both contain it, 
 some brick residences in Reno are much improved by its use; 
 
and the new Elk's Hall shows it to advantage. This tuff should 
 be much used for the demands befitting it. 
 
 North of Reno : This tuff comes from a mass of consolidat- 
 ed ash almost twenty miles northeast of Reno, on the Spanish 
 Springs Valley road. A little stone has been quarried and used 
 in Reno in ways similar to the Merrimac rock. It's color is a 
 light pink, a little lighter than the first material. These two stones 
 are very similar in their features and can be used in precisely the 
 same ways and for the same demands. This second tuff, however r 
 is more irregular in texture, containing angular fragments of oth- 
 er rocks, largely andesite and granite, thereby appearing some- 
 what mottled when closely inspected. It tempers slightly better 
 that the other. Careful selection should eliminate the unsightly 
 stone from that quarried. The owner is Mr. Wm. Schrader, of 
 Reno. 
 
 Lovelock : This rock is located in the hills to the northeast 
 of the town of Lovelock, on the line of the Southern Pacific 
 railroad. The point from which it has been obtained is about four 
 miles from the station with not a hard haul over the distance. 
 The color is a purplish-gray, of a medium depth of tint. The 
 structure and texture are in general the same as in the other tuffs. 
 Many small fragments of volcanic rocks are interspersed through- 
 out the mass, and small glassy cystals of feldspar are quite noti- 
 cible on careful inspection. The rock inclusions are dark gray, 
 so that a close view exhibits many seeming imperfections in grain. 
 Used in a building these are not apparent, and the whole aspect is 
 a very pleasing one. The usual shade of purple will give a pret- 
 ty contrast with other stones whose color blend with its, own. 
 The hardness and strength are good, ranking well up with that of 
 the best sandstone, while at the same time it is resistant to atmos- 
 pheric changes. A vast amount is in sight, and when once intro- 
 duced, a ready market should follow. 
 
 Washoe : A rock similar, yet different, from the three tuffs 
 mentioned, is found at Washoe, on the Virginia and Truckee 
 railroad. This notice is of value chiefly from a historical stand- 
 point, as several of the old abandoned buildings of the once thriv- 
 ing town are made wholly of this stone. In it's nature it is a 
 volcanic agglomerate, or a consolidated volcanic mud, 'and an 
 unusual material for purposes of construction, The old quarry 
 is on the hillsides above the railroad track just north of Washoe 
 station, in a surface cut only a few feet in the mass. One is 
 tempted to describe it as having a mud color, this feature is so 
 
very inconspicuous. More specifically the color is mottled light 
 and medium dark gray, and the surface usually appears dusty The 
 texture is quite porous. Nothing in the way of definite substances 
 or minerals can be easily determined or distinguished. It's last- 
 ing qualities rank with an average sandstone, but its strength is 
 less. It is easily available, but its use cannot be urged in the face 
 of much more and better stone. 
 
 ATMOSPHERIC ROCKS 
 
 SANDSTONES 
 
 Nevada has had developed up to the present time only a few 
 rocks of this family, and none of them can be called first-class. 
 They are all of recent geological age, and owe their qualities 
 to their youth. As the development of the state goes on, more 
 such will surely be found, perhaps some of the very best. These 
 stones will be needed as the cities and towns grow, and the best 
 will command a good price. 
 
 Carson : The first and most important sandstone is the well 
 known one at the State Prison, near Carson. The quarry consti- 
 tutes the prison yard, and has had the most work done of any in 
 the state. The sandstone beds or strata occupy the site of an ex- 
 tinct lake, and exhibit the quite famous animal tracks on the pres- 
 ent floor. The color is a yellowish-gray, a gray unfortunately, 
 streaked with a light yellow, and not uniform. The rock is rather 
 heavily bedded, with the bedding planes nearly horizontal. This 
 position is probably the same one the stone has always occupied, 
 although slight tilting may have occurred. On this account, of 
 horizontality, quarrying is easily done. That mineral content 
 shows the stone to be derived from the weathering and decom- 
 position of a granite, the yellowish tinge being due to the oxidation 
 of the iron bearing substances. The constituent grains are ce- 
 mented by secondary silica. The grain of the rock is of medium 
 fineness in the average, but at times becomes quite coarse, con- 
 taining pebbles up to half and inch in size. The hardness and 
 strength are medium, sufficient for all ordinary needs, and the re- 
 sistance to other forms of change is good. There is much ma- 
 terial in sight at the prison yard. The stone has been used largely 
 in Carson and Reno. The new chemistry building at the Univer- 
 sity is constructed wholly of it, and presents a very satisfactory 
 appearance. A small amount has found a resting place in the 
 stone entrance to the University grounds, as is shown in the front- 
 ispiece. v 
 
Fall-on : This sandstone occurs near the town of Fallon, in 
 Churchill county. Little quarrying has been done, but samples of 
 the rock show its main features. In color it is a cream white very 
 uniform in the small pieces shaped for exhibition. The grain, 
 too, is uniform, and quite fine. It's hardness and strength are 
 about equal to those of the Carson stone, and satisfactory. It 
 should resist the weather well, and appear to be a very fair stone 
 for building purposes. Mr. L. B. Self, of Reno, is the owner. 
 
 Winnemucca: There are two varieties of these stones quar- 
 ried near and used in Winnemucca. Neither are first-class in any 
 respect, though they do well enough for the local uses. They 
 are taken from the old lake beds, to the northeast of the town. 
 
 The first stone is quarried nine miles from the railroad sta- 
 tion and hauled in by team. The color is a light drab, and quite 
 uniform. The minerals and substances comprising the stone do 
 not show, on account of the fineness of the grain. Some black 
 flakes of mica are noticible, but nothing else. The hardness and 
 strength are low, too low for anything but the smaller structures 
 and the uses ' demanding little power to withstand pressure or 
 stress. It stands temperature changes well, and were its strength 
 higher would be an admirable building stone. Some new build- 
 ings have recently been erected in Winnemucca composed largely 
 of this stone. Such local uses are well met, but the demand for 
 such a rock will of necessity be limited to the town itself. Mr. 
 Joe Pasquale is owner of the stone. 
 
 The second variety of sandstone is quarried from a point four 
 miles from the town, and much more available. However, the 
 quarry has been abandoned, on account of numerous faults and 
 breaks in the material, which render the cost of obtaining stone fit 
 for building almost prohibitive. The color is a light gray; the 
 texture is coarser than in the first variety, and somewhat variable. 
 The hardness and strength are considerably more than in the 
 first, so that were the stone to be easily obtained its use would be 
 wide. New developments later may show different and more 
 favorable conditions. The new fire company house in Winne- 
 mucca shows a handsome front of this material. Mr. Pasquale 
 is owner of this stone, as of the first. 
 
 Elko : At Elko there is a sandstone much like the first one 
 described from Winnemucca. As with the rest of the soft ma- 
 terials, its use is limited to small buildings, where the strain upon 
 it is light. The local demands are met sufficiently well by it, but 
 it can never have wide use. There is surelv much first class build- 
 
ing material to be developed in this part of the state as the popula- 
 tion increases. 
 
 MARBLE. 
 
 The marbles in Nevada are well represented, although little 
 has been done to develop them. Only a few are quarried, due, of 
 course, to the scattering demand and difficulty of gaining a market 
 against other stone now used. It should not be many years before 
 a steady market is open to them, not only in this state, but iln 
 others as well. 
 
 La Moille Valley: On the borders of this valley, in Elko 
 county, exists a vast amount of a fairly good variety of marble. 
 No quarrying has ,J^en done, but some stone has been -taken- out 
 to show its character. The color is white in one variety, and a 
 gray, or a laminated gray and white, in another. The white is 
 clear, not marked by yellowish spots or flaws. The stone is rather 
 finely crystalline, and takes a good polish. The marbles are all 
 hard, brittle, and easily, though slowly, soluble in atmospheric 
 waters, as has been discussed in a previous chapter. - The rock is 
 not very far from transportation facilities, and should meet with 
 some demand. The uses are mainly interior ones, such as tiling 
 for floors, mantels, mosaic work, and others. Mr. W. T. Crane, 
 of Lee, Elko county, is the owner. 
 
 Humboldt Mountains: In these mountains a considerable 
 amount of coarsely crystalline marble exists, which may prove of 
 some value upon more careful investigation. What rock has been 
 seen shows a pure white color with few impurities appearing on 
 weathering. This is not the only place where such rocks are 
 known to exist ; it is cited merely as an instance of the little knowi- 
 edge regarding these things. 
 
 Luning: More marble, of gray and white colors, exists in 
 the region in the vicinity of Luning, Esmeralda county. Some of 
 this has been quarried and used by Mr. Lindsay, of Carson, and it 
 ranks with the others mentioned. It outcrops on the line of the 
 Carson and Colorado railroad, hence is easy of access, which is a 
 strong point in its favor. More facts concerning it are needed. 
 
 Topaz, California : Considerable marble is found in Antelope 
 Valley, in California, opposite Douglas county, in this State. As 
 its use and development comes naturally through Nevada, it needs 
 a mention here. The stone varies considerably in color, from white 
 to blue, gray, and yellow. As the locality is off the railroad, the 
 development work has lagged, but the rock deserves some atten- 
 
tion in the near future. The uses are those already mentioned. 
 Mr. Lindsay, of Carson, owns much of the material. 
 
 Inyo County, California: Considerable marble has been 
 quarried in Inyo county, California, and used both in Nevada and 
 California for tiling, mantels, mosaic work, and such demands. 
 Some of the rock is laminated ; most is not, but cracks and flaws 
 are quite common. There are three distinct colors of the marble , 
 white, yellowish-white, and dark gray. The contrast between 
 these is very pleasing to the eye. The lasting qualities are the 
 same as the other stones of like nature possess. The stone works 
 on the Truckee river above Verdi are handling this rock almost 
 entirely and have some large contracts on hand. 
 
 TRAVERTINE). 
 
 Bridgeport, California'. This variety of stone is related to 
 the limestone, having been deposited by springs. A great deal of 
 these deposits are to be found over southeastern California, Ne- 
 vada, and Arizona, marking the sites of old springs. The only 
 occurrence yet exploited in or near Nevada to any extent is nelar 
 Bridgeport, in Mono county, California. The stone is a variegated 
 reddish, and yellowish, very handsome when polished. It was 
 used in the new City Hall in San Francisco. The work of exploi- 
 tation needs to be carried farther, as it will be when more demand 
 is made for the material. Its uses are purely ornamental. 
 
 It is needless to say that very many more stones suitable for 
 purposes of construction exist in the State. Only those actually 
 used, and those about ready to be used, have been listed. There 
 are many more known ; there are vast amounts to be discovered. 
 
 The frontispeice shows a number of the rocks mentioned ac- 
 tually in use in the "University Gates." The large columns sup- 
 porting the gates are made from granite taken from boulders near 
 Reno. The smaller pillars just outside are composed of Washoe 
 granite, a shade darker than the first. The stone wall exhibits 
 two more. The first, or ground course of blocks in the wall to the 
 left is made of the andesite from the Fulton quarry, north of Reno. 
 The upper three courses of stone are all the Carson sandstone. 
 The finish throughout is rough, and the appearance very pleasing. 
 
CHAPTER V. 
 
 ROAD METAL AND SOME GENERAL PRINCIPLES OF ROAD MAKING. 
 
 This subject does not come strictly under the head of building 
 stones, yet its vast importance to the welfare of any community, 
 together with the fact that some knowledge of rocks is essential 
 to a proper understanding of it, more than justifies a short chapter 
 setting forth a few fundamental considerations. The bicycle and 
 other horseless vehicles have done one great work, if nothing else ; 
 they have shown conclusively to all people the value and immense 
 importance of good roads. 
 
 Time was when the old earth road was held sufficient for all 
 needs, and such roads were not even crowned. We still have many 
 earth roads, which, when properly compacted and graded, do well 
 enough for light traffic in sparcely settled regions. Where travel 
 is at all heavy, however, earth roads become a makeshift, and 
 some material which will not cut to pieces is needed. Very natur- 
 ally, men have turned to rocks to furnish such material, termed in 
 general, "road metal." The roads made by crushed rock on an 
 earth foundation are called macadam, from the name of the man 
 who introduced them. 
 
 For the purposes of road construction we have a vast abun- 
 dance of rocks of various kinds and character. Bearing in mind 
 the classification of rocks in Chapter II, we realize the range of 
 choice. All of the igneous, atmospheric and metamorphic rocks, 
 of hardness greater than earth, might be used. By clas the 
 igneous rocks are hardest, the atmospheric, softest; the 
 igneous are more or less crystalline, the atmospheric large- 
 ly fragmental. The metamorphic rocks are intermediate in 
 their qualities. In Nevada there is a large development of all 
 these kinds, easy of access. But this wide range of choice not 
 only furnishes abundant possibilities, but also allows the selection 
 of the best. It must be self-evident that all road materials are not 
 of equal, nor anywhere near equal value. There is always a best 
 and a poorest for every case. In order to select the best road 
 metal for a certain street or road, a knowledge of the principles 
 underlying such choice must be had. A brief account of these will 
 be presented. 
 
 The fundamental fact on which all road making is clone is 
 the simple one that a highway is constructed to withstand constant 
 wear. It must first be known, therefore, of what this wear con- 
 sists. The wasting of a road is due, first, to chemical agencies; 
 second, to physical agencies ; and, third, to mechanical agencies. 
 
The chemical agencies are those constantly at work in the atmos- 
 phere, and producing (i) solution and (2) decomposition, as, 
 pointed out under building stones. The physical agents are like- 
 wise atmospheric, and are: (i) frost, producing disruption of 
 the road and of the individual rock fragments; (2) the effects of 
 rain falling on the surface, running off, loosening the road sur- 
 face and transporting the material away; (3) the wearing effects 
 of the wind in carrying off the fine particles as dust. The mechan- 
 ical agencies are due to the action of living things ; the wearing 
 down and grinding up of the surface ; the crushing effect of heavy 
 loads and impact of of the feet of animals; and the possible injur- 
 ious effects of roots. With roads properly constructed, of those 
 forces tending to impair their usefulness the physical and mechan- 
 ical agnets are most important. 
 
 Enough has been written of chemical agencies under a pre- 
 vious head, so that a mere mention is all that is here necessary. 
 Such processes in nature are so slow that roads suffer little com- 
 paratively from them. However, chemical reactions play an im- 
 portant part in the process of compacting, or binding a road bed 
 and making it durable. This power of binding, or cementing, in 
 a road metal, is an essential quality, and the higher it is the better. 
 All other things being equal, the ideal road material is that one 
 which will furnish a large percentage of mineral, or minerals, that 
 do not alter or which change very slowly, with some other mineral 
 or minerals capable of furnishing, by slight decomposition, suffi- 
 cient cementing substance to bind the whole together as a solid 
 mass. The particular minerals best fitted to accomplish this end 
 are those containing iron and alumina, with silica. Lime bearing 
 minerals also are valuable. By way of a homely illustration, this 
 process may be likened to a sidewalk made of nails, which, on 
 being allowed to remain for some time, becomes rusted into a 
 solid condition. There are several more important binding mate- 
 rials, as clay, secondary iron minerals, calcite or lime, and some- 
 times silica. These must form, in order to be of greatest good, 
 in just the right amount to bind the gradually pulverized surface 
 coating, as well as to harden the whole. 
 
 Of the physical agencies, in regions of considerable range 
 of temperature, the action of frost may be of some moment. As 
 mentioned under rock weathering, water, entering the pores of 
 a stone and in cracks, on freezing becomes a powerful lever tend- 
 ing to disrupt the material. Also, the mere alternate cooling and 
 warming by daily variation, gradually weakens a rock. In mild 
 climates these things play no part. The effect of rain in loosen- 
 
ing and wearing away the road surface may become a source of 
 danger in poorly constructed highways. The greater effect of 
 rain is its power of transporting the layer of fine material neces- 
 sary on every well kept road. This action is measured by the 
 specific gravity of the minerals composing the rock surface, their 
 shape, and their state of compactness. For instance, mica is a 
 poor miner to have in a road metal, because of its flaky nature 
 which allows of its easy transportation by the rain and wind. 
 The selection of a stone must consider all these points. In like 
 manner the winds are constantly picking up and carrying off as 
 dust the lightest rock flour from the surface, often sweeping the 
 streets clean of loose fragments and depositing dust over nearby 
 houses and vegetation. Thus, the rain and wind, together or 
 singly, are mainly responsible for the loss of that layer of finely 
 ground rock which should constantly cover the top of every road 
 and street a small fraction of an inch in thickness. 
 
 The mechanical agencies are the most easily s,een, and are 
 chiefly the grinding and pounding of the travel over the high- 
 ways, The pulverized surface is thereby constantly loosened 
 ready for the wind or rain, and just as fast as this disappears more 
 is worn from the underlying rocks to replace it. Also, if the mass 
 of the road be not well compacted, it will loosen, tending to form 
 "chuck holes." Obviously, the heaviest traffic will do the most 
 damage, and will be the most difficult to meet. The disrupting 
 effect of roots should be reduced to nothing by a proper construc- 
 tion of the road bed. 
 
 Keeping these considerations in mind, it can be seen that a 
 choice of road metal is made by considering for every case ( I ) the 
 requirements which the road must fulfill; and (2) the power of 
 given materials to meet these conditions. In any one locality the 
 mechanical wear and tear is all that varies appreciably, the rest 
 remaining practically constant. In other words, the traffic changes 
 from place to place, so that we need harder and firmer highways 
 in a city than in the open country. These five divisions of traffic 
 are commonly made to denote this: City (perurban), urban, 
 suburban> highway, and country road. City traffic is that existing 
 on the streets of large cities, and no ordinary macadam can with- 
 stand it. Stone and wooden blocks, asphaltum, vitrified brick, and 
 some few other substances are commonly used. Urban traffic is 
 that common to city streets not used for continuous heavy team- 
 ing. The hardest and toughest macadam must be used, for the 
 wear is heavy. Suburban traffic is, as the name denotes, that 
 found on city streets in their outer limits, and in the main thor- 
 
oughfares of country towns. A rock of less hardness and tough- 
 ness is required. Highway traffic is that found on the main coun- 
 try roads, for which a material of medium qualities should be 
 used. Country road traffic exists on the less used roads in the 
 least settled districts. A comparatively soft rock is needed in these 
 localities. This division of traffic is purely arbitrary, yet of the 
 greatest importance. At first thought it might appear that a rock- 
 well fitted for the heaviest traffic would surely be satisfactory for 
 lighter travel. No greater mistake could be made. The two op- 
 posed forces : the wear on a road, and the hardness, toughness 
 and binding power of the material used, giving resistance to 
 wear, must actually balance each other to give the highest results 
 in any given case. The road surface, composed of the necessary 
 layer of fine material, must be renewed just as fast as it disap- 
 pears. In other words, speaking broadly, as fast as the wind and 
 water carry away the materials from the top of a road, just so fast 
 should the under rock fragments grind down under travel to 
 form new surfacing. The amount of work done by the wind and 
 water should be reduced to a minimum by selecting a road metal 
 with maximum binding quality. Then the other qualities of the 
 stone must be fitted to the needs of the travel destined to be over 
 it. If too small a supply of fine surface material, or "binder," be 
 furnished, because of too light traffic for the particular stone used, 
 the road "ravels," and the underlying rock fragments project, 
 making the road rough as well as weak. If too much protecting 
 surface be supplied, from too heavy traffic, the excess results in 
 dust or mud. In a moist climate a thicker layer of surfacing is 
 permissable than in a dry climate. 
 
 Having these few fundamental considerations in mind, it is 
 possible to choose a road metal with greater chances of its success. 
 The three main characteristics which must be considered first are 
 hardness, toughness, and binding power. Hardness is the resist- 
 ance of a rock or mineral to rubbing, as by grinding on an emery 
 wheel, and to force applied to crush the stone. Toughness is thq 
 resistance to fracture by blows, as continually delivered upon a 
 road by travel. The cementing power has been explained as due 
 to slight chemical change in the rock. It is also due, in small 
 part, to the mere presence of a little moisture. It is well krfbwn 
 how firm wet sand is compared to dry. In all cases, a slight per- 
 centage of water in the mass of road material is necessary. There 
 is, naturally, much diversity of opinion regarding the values of 
 the various road materials. A rock suitable in all respects for one 
 locality may easily prove a total failure in another. A stone much 
 
affected by frost should not be used in a cold region, nor will a 
 brittle one give the best results in a dry climate. It appears to be 
 the consensus of opinion that, all things considered those rocks 
 called popularly "traps" are the best. These rocks are found 
 typically as dykes, hence are intermediate in texture, and are 
 largely diabase and diorite. They are among the toughest of the 
 rocks, and usually have good binding power. The best varieties 
 of these traps make satisfactory roads for urban traffic, but are 
 too hard and tough for the lighter travel. The finer grained 
 plutonic rocks probably come next in order of value, the more 
 basic being the best as a rule, because of better cementing qualities. 
 Granite is often frowned upon, yet some granites have given good 
 results. The presence of hard, but brittle, quartz seems to be the 
 chief objection, while micaceous granites, as well as all rocks con- 
 taining mica, are unsatisfactory. However, given a binding 
 power in a stone, any ordinary amount of free quartz is of real 
 value, because it is not decomposed under ordinary conditions, 
 and furnishes an unchanging base for the road. The volcanic 
 rocks are of varying values. Basalt blocks are used for paving 
 for city traffic, but for macadam their field is limited. Preference 
 is given the crystalline rocks. Rhyolites, with sufficient binding 
 power, have given excellent results in some localities. Andesites 
 might also make good roads. The crystalline metamorphic rocks, 
 the gneisses and schists have been uajed with good results. Of 
 the atmospheric rocks, few seem to find favor. In the West, es- 
 pecially in California, such rocks have been largely used, with 
 eminent success. In Golden Gate Park, San Francisco, a dark red 
 chert has furnished material for the excellent roads, which are 
 among the finest in the State. At other points around San Fran- 
 cisco bay, and in the interior valleys, where the climate is much 
 like that of western Nevada, a metamorphic sandstone has made 
 fine roads. Also, a dark basic diorite has been used for heavy 
 traffic with satisfactory results. Limestone would seem on the 
 face of the matter to be almost worthless as a road metal, yet some 
 roads have been constructed of it in the east with great satisfac- 
 tion. Some varieties^ are hygroscopic, that is, attract moisture 
 from the air and might prove of service in a dry climate. Here 
 in Nevada, and particularly near Reno, where the construction of 
 stone roads will begin, there are several promising rocks. An 
 immense supply of rhyolite containing considerable iron outcrops 
 less than a mile north of Reno, and an abundance of a medium 
 basic granite, much of it without mica, or with little, exists to the 
 south and west. The latter rock, considering the traffic, might 
 
easily prove a success. Andesite and basalt, of unknown value, 
 are also near by. The reddish andesite used in the Carnegie 
 Library should make an excellent material for light travel. More 
 rock of a similar nature is to be obtained in abundance at Huf- 
 faker's, on the line of the V. & T. railroad. The diorite of Mt. 
 Davidson, and much of the unaltered rock extracted in the mines, 
 should make a satisfactory rock for heavy traffic. Crystalline 
 limestone, or marble, occurs in large amount in the eastern part 
 of the state, as do many other desirable rocks for road metal. 
 The possible value of lime rocks for road purposes in this dry 
 climate has already been mentioned. 
 
 But in spite of these few general principles, and list of pos- 
 sible materials, there comes the one question "will such and such 
 a stone be a success?" We are apparently confronted by the 
 truth of the old maxim "the proof of the pudding is in the eating." 
 Very fortunately, however, we are not driven to the necessity of 
 actually constructing roads merely to test certain materials. The 
 application of general principles to measurements of the various 
 qualities of a rock not on a road building scale will tell almost 
 everything needed in the way of information. Laboratories for 
 the testing of road materials have been installed at several places 
 in the United States. The two of particular value to Nevada are 
 the laboratories at the University of California and at Washington, 
 D. C., under the Department of Agriculture. In the latter case, 
 any person may have a full test made of a rock for road construc- 
 tion free of charge, the only expense being that of freight charges 
 on the railroad. Requests for blank forms and instructions should 
 be addressed to the Road Materials Laboratory, Office of Road 
 Inquiry, Department of Agriculture, Washington, D. C. Full 
 tests are made, and the fitness of a stone for road material is given 
 in detail. The laboratories at the University of Nevada are poorly 
 equipped to make more than a few simple tests, for special appara- 
 tus is required. Considerable aid can and will be given to interested 
 parties, however. 
 
 Although much in the way of principles underlying success 
 in road construction have thus far been given, the most important 
 condition of all has been assumed complied with, namely that the 
 road be properly constructed. It lies beyond the scope of these 
 few notes to enter upon the engineering side of road construction, 
 and it is only urged upon the citizens of Nevada to inform them- 
 selves before commencing the building of stone roads. A perusal 
 of the few references given at the end of the chapter will furnish 
 all the facts necessary, and every voter should be acquainted with 
 
them. Macadam roads cost from $4,000 to $10,000 a mile, and 
 an error in construction or judgment in selecting suitable material 
 may mean great loss to a community. 
 
 There are two more materials which deserve serious con- 
 sideration used in constructing roads. The first, and perhaps 
 of little adaptability or value to most of Nevada, is vitrified 
 paving brick, laid like ordinary basalt blocks in a road. Roads 
 of this nature have proved very efficient in the esat, especially in 
 the prairie States, and may prove of value elsewhere. A reference 
 covering the subject is given. The second material is of the 
 greatest value and adaptability to Nevada, with her dry climate. 
 The unqualified and immense success of oil on roads, laying all 
 dust and making a surface as smooth as asphaltum, recommends 
 it as a possible boon to this section of the country, where water is 
 scarce. When properly used, its success has always been immedi- 
 ate and great, and the consideration of its use is earnestly urged 
 upon the citizens of this state. Its cost is nominal, and is partially 
 compensated by the dec r ease in the cost of watering the streets 
 treated. Some of the sandiest and dustiest roads in southern 
 California have been made into perfect highways by its use, the 
 result being much like a bituminized rock surface. 
 
 The following list of references will be found useful to all 
 those interested. They may be obtained free of cost by applying 
 to the Secretary of Agriculture, Washington, or at the Experi- 
 ment Station at the University of Nevada. 
 
 (i.) "The Forces Which Operate to Destroy Roads, With 
 Notes on Road Stones and Problems Therewith Connected." Cir- 
 cular No. 29. Office of Road Inquiry, U. S. Dept. of Agric. 
 
 (2.) "The Selection of Materials for Macadam Roads.'' 
 Yearbook of Dept. of Agric., 1900. 
 
 (3.) "Historical and Technical Papers on Road Building in 
 the United States." Bull. No. 17. Office of Road Inquiry. 
 
 (4.) "The Testing of Road Materials.'" Bull. No. 79. Bu- 
 reau of Chemistry, Dept. of Agric. 
 
 (5.) "Methods of Constructing Macadamised 1 Roads." Cir- 
 cular No. 21. Office of Road Inquiry. 
 
 (6.) "Highway Repairing." Circular No. 24. Office of 
 Road Inquiry. 
 
 (7.) "Brick Paving for Country Roads." Circular No. 25. 
 Office of Road Inquiry. 
 
(8.) "Earth Roads." Farmers' Bulletin No. 136. Dept. of 
 Agric. 
 
 (9.) "The Use of Oil on Roads." Year book of Dept. of 
 Agric., 1902. 
 
 (10.) "The Social, Commercial and Economic Phases of the 
 Road Subject." Circular No. 34. Office of Road Inquiry. 
 
 (n.) "Going in Debt for Good Roads." Circular No. 26. 
 Office of Road Inquiry. 
 
 (12.) "Wide Tires." Bull. No. 12. Office of Road Inquiry. 
 
CHAPTER VI. 
 
 CONCLUSION. 
 
 There are a few points to be emphasized and a few explained 
 before bringing this paper to a close. The real need of such pub- 
 lications, incomplete as they must necessarily be in a new and 
 undeveloped State like Nevada, is surely apparent to all pro- 
 gressive citizens. The vast size of the unknown and undeveloped 
 in the State is almost appalling when contrasted with what little 
 is known. And the work of the future, the proper opening up of 
 the State in all possible ways, depends largely upon the methods 
 of its accomplishment. The haphazard stage has been passed, 
 and we must build solidly and scientifically. The bonanzas have 
 been exhausted from the great Comstock, and the future of that 
 famous lode rests upon the scientific mode of attacking the prob- 
 lem now present : that of working immense bodies of low-grade 
 ore at a profit. And with the agriculture of the State, that indus- 
 try which heretofore lagged behind the rest, the great problems 
 of irrigation are fundamentally connected. Every detail must be 
 worked out scientifically, in accordance with law and order. 
 Likewise with the building stones of Nevada. No order, and little 
 real knowledge has governed the choice and use of materials in 
 the past. No harm has been done, because the needs were few 
 and simple. But with the growth of large towns and cities, new 
 and great buildings will be required, and real scientific facts about 
 the materials of construction available will be needed. And so 
 with many other lines of human activity. We need not only to 
 know, but to know in the right way ; to have scientific knowledge, 
 to understand law and truth. It is largely to aid in bringing about 
 the acceptance of such considerations that this paper has been 
 written. 
 
 Regarding the subject matter, a few words of explanation 
 seem necessary. First, the rock classification may strike petro- 
 raphers as rather behind the times. It is, and necessarily so. The 
 tendency of modern petrographic thought ts toward the drawing 
 of fine lines, and the classification of rocks in accordance with new 
 ideas and conceptions. This is all necessary and right, but the 
 unitiated have no use for such terms as "persalane," "dofemic,"' 
 and the rest. A popular terminology will and must always be 
 distinct from the petrographic, if such names are universally 
 adopted by scientists. The main idea underlying the writing of 
 the chapter on the classification of rocks is this: To 
 convev some definite idea to the practical man re- 
 
garding the meaning of the general names of rocks, with 
 the characteristics appertaining thereto . Very unfortunately, it 
 seems to the writer, that with the advent of more exact petro- 
 graphic nomenclature must come more or less of a dual classifica- 
 tion of rocks. The old terms are good and sufficient for all prac- 
 tical needs, and need no change for these purposes, no 
 matter to what lengths the more exact terminology 
 may go. Moreover, they cannot be changed, for obvious 
 reasons, and this must not be forgotten by the scientist in his 
 search after truth. 
 
 The chapter on the qualities of building stones is complete 
 enough for the purposes of the present paper but will need more 
 details for a larger report. The larger facts are, of course, given 
 in full. Amplification of the methods of testing building ma- 
 terials is likewise needed when a final report is issued. 
 
 Regarding the rocks themselves, the list brings to light some 
 important facts. It is to be seen that at present some amounts 
 of stone are used, and that this use is daily increasing. Also it 
 is stated with the awakening of the State to new and better times, 
 a great increase in stone buildings will occur. But the cardinal 
 point is this: So very little is known definitely about Nevada; 
 the welfare of the State depends largely upon this knowledge of 
 her resources, not only in the one small line of building stones, 
 but in all the ways of human activity. This thought should not 
 be lost sight of for an instant. 
 
 The chapter on road metal is included because it is believed 
 to fill a real need for information. Reno must soon lay new streets 
 to meet the demands of an increasing population, and it will not 
 be long before some of the other large towns follow suit. And 
 road construction, like many other engineering works, looks easy 
 to the uninstructed. To the business man, mining appears 
 to consist of digging a hole and taking out ore. Likewise to the 
 same ordinary man of business, road making seems to consist 
 merely of dumping a lot of rock on a road and smoothing it off a 
 bit. Both ideas are greatly in error, and it is high time every good 
 citizen knew something of the proper construction of roads. And 
 it is to be remembered that it is not always, nor often, that the 
 street which costs the least to construct is the cheapest. 
 
 Lastly, it is to be stated that all in his short paper has been 
 written in the dawn of the light coming from the new day of 
 prosperity for the State of Nevada, with her boundless wealth of 
 material things just beginning to awaken due appreciation. 
 
333114 
 
 UNIVERSITY OF CALIFORNIA LIBRARY