PROSPECTING, LOCATING 
 
 AND 
 
 VALUING 
 
 A Practical Treatise for the use of Prospectors, Investors and Mining Men. 
 
 generally; with an account of the Principal Minerals and Country Rocks; 
 
 Ore Deposits; Locations and Patents; the Early Development 
 
 of Mines; Earthy Mineral Products; Coal; Gold Gravels 
 
 and Gravel Mining; Measurement of Water; 
 
 and Artesian Wells. 
 
 WITH FIFTEEN PLATES. 
 
 BY 
 
 R* R STRETCH, E.M* 
 
 SECOND EDITION. 
 
 THE SCIENTIFIC PUBLISHING COMPANY: 
 
 NEW YORK AND LONDON. 
 1900. 
 
 206 BOSTON BUILDING^ 
 DENVER, COLO. 
 
COPYRIGHT, 1899, 
 
 BY 
 THE SCIENTIFIC PUBLISHING COMPANY 
 
CONTENTS. 
 
 I. Introductory Mistakes in Mining. ....... 1 
 
 II. What Constitutes a Mine . . . r , 16 
 
 III. Rock-forming Minerals and Rocks 3 . . . . t 36 
 
 IV. Physical Character of Mineral Deposits 69 
 
 V. Origin of Veins , . 83 
 
 VI. Filling of Mineral Veins 4 . . , 99 
 
 VII. Influence of Rocks on Vein Filling , . , 120 
 
 VIII. Mineral Deposits Other than Veins . . , 138 
 
 IX. Prospecting . . . . a . 150 
 
 X. Making Locations ;>." 167 
 
 XI. Patents to Mining Ground 187 
 
 XII. Early Development of Mines. . * 197 
 
 XIII. Ores .. ... 206 
 
 XIV, Useful Earthy Minerals, etc 229 
 
 XV. Coal ,.,o 259 
 
 XVI. Gold Gravel Deposits 271 
 
 XVII. Water and Its Measurement 302 
 
 XVIII. Artesian Wells 310 
 
 Useful Tables 316 
 
 Good Books of Reference.. 338 
 
 Plates 1 to 15 inclusive. , 344 
 
 Index... . 374 
 
 438579 
 
PROSPECTING, LOCATING 
 
 ..AND.. 
 
 VALUING MINES. 
 
 CHAPTEK I. 
 INTRODUCTORY MISTAKES IN MINING. 
 
 THE following pages are not intended for those who 
 have devoted a lifetime to mining and are educated in 
 the many branches of knowledge which go to make the 
 successful mining man, but for those who would like to 
 invest a portion of their capital in the business if they 
 felt safe in so doing, and who hold back because of 
 their complete ignorance of the subject ; and to restrain 
 the over-sanguine temperaments of others, by pointing 
 out the elements which may militate against success. 
 At the same time it is believed that the prospector will 
 also find hints which will assist him in his \\ ^arisome 
 labors, enable him to ma*ke his locations to better ad- 
 vantage than is now the case in a very large proportion 
 of those on record, and furnish him with the language 
 in which he can intelligently describe to others what 
 he has found, so that they shall see it just as he does, 
 and be able to verify his statements upon inspection. 
 
 It is hoped that the explanations and suggestions 
 will, to some extent at least, prevent him from spend- 
 ing time and money on valueless prospects or worthless 
 minerals; furnish him with the means to determine 
 approximately the value of what he has found, and 
 
2 PROSPECTING AND VALUING MINES. 
 
 show him the way to develop it at the least expendi- 
 ture of time and labor; and enable him to see clearly 
 what nature has done to his advantage, or the obstacles 
 which have been thrown in his way. 
 
 It is not pretended that new geological facts have 
 been presented. Nearly all of them can be found in 
 the books, but they are scattered through many and 
 often expensive works, and in but few cases is there 
 any allusion to the practical bearing of these facts on 
 the interests of the miner, except in the case of coal 
 mining, which has a complete and extensive literature 
 of its own. In all these works, geology, in its relation 
 to coal mining, receives full attention, but it has been 
 otherwise with vein mining for the precious metals. 
 Where it would be impossible to put the subject matter 
 into better language, the writer has quoted freely from 
 recognized authorities, and has used some illustrations 
 which may almost be called common property from 
 the frequency with which they have been copied by 
 one writer after another; but a large proportion of the 
 illustrations are drawn from the writer's own note- 
 books. 
 
 The object of the book may be best illustrated by 
 a few words on the causes of failure of mining enter- 
 prises which it is sought to avoid by calling special 
 attention thereto. In mercantile business, failures 
 arise from undue competition, depression in trade, 
 wrong selection of location,* want of capital, lack of 
 business tact, want of knowledge of the trade, etc. In 
 gold mining, and to a certain extent in silver mining, 
 we get rid of the element of competition ; and in gold 
 mining, at least, depression in trade does not affect 
 otherwise than as a stimulus, but ail other causes 
 operate in very much the same manner both in mining 
 and trade. 
 
 It should be kept in mind that every pound of ore 
 taken from a mine leaves just that much less in it, and 
 that the end must inevitably come at some time. In 
 
INTRODUCTORY. 3 
 
 this respect a mine differs essentially from a mercan- 
 tile business which can enlarge its field of operations 
 year after year as population increases or facilities of 
 communication are improved. If the mine only yields, 
 above working expenses, a sum sufficient to repay the 
 cost of the ground, development and plant, the investor 
 might just as well have buried his dollars for the same 
 period of time, and saved labor and mental strain. 
 This state of affairs may easily occur even when the 
 mine has rich ore in sight. 
 
 It takes just as deep a shaft to open a piece of 
 ground 500 ft. long as if it were 2,000, but the cost of 
 sinking and pumping, and all expenses of corporate 
 management will be four times as great per square 
 foot of area developed in one case as in the other, and 
 this difference may do away with the possibility of 
 dividends or even the recovery of the invested capital. 
 
 Numerous cases of this kind have been seen in Colo- 
 rado and elsewhere, where small properties which 
 could not stand the burdens thus imposed upon them 
 have proved successful when consolidated, one shaft 
 answering for a much larger property, thus saving the 
 cost of constant sinking, the expense of numerous 
 engines and surface hands, as well as superintendence 
 and office expenses. 
 
 On the other hand an enterprise may have so much 
 ground that the energies of the company are scattered 
 over too large an area, one unproductive section eat- 
 ing up the profits of the better ground, thus leading 
 to constant embarrassment; and a failure under these 
 circumstances may do as much to blast the reputation 
 of a district as if the property had been absolutely 
 barren throughout. 
 
 This condition of the mine as regards its capital 
 renders it undesirable, if not dangerous, to experiment 
 with new processes of reduction. So many of these, 
 while eminently successful in the laboratory, when 
 worked on a small scale and by enthusiasts thoroughly 
 
4 PROSPECTING AND VALUING MINES. 
 
 posted on all the minute details, have proved so inap- 
 plicable on a large scale, when operated by less careful 
 men, that a mine cannot afford to employ them until 
 they have proved entirely satisfactory under all similar 
 working conditions. The cost of the experiments 
 should be borne by the projectors of the innovations; 
 all that a mine dare do is to pay a royalty or purchase 
 the machinery when it is no longer an experiment. 
 It is true that the improved machinery, so called, 
 might be a real improvement and a desirable acquisi- 
 tion, but on the other hand, if a failure, it would be 
 only another tax on a treasury which has already its 
 full share of burdens. 
 
 Again, the price given for a mine may be so exorbi- 
 tant, or out of proportion to its development, that 
 while it may pay dividends for a time and apparently 
 be a success, the ore body may "peter out" before the 
 purchase price has been returned in the shape of divi- 
 dends; and failure will ensue, unless a reserve fund 
 has been set aside, with which to search for other ore 
 bodies, The disproportionate profits of the middlemen 
 or promoters emphasize this proposition, as in the 
 case of the Kichmond Consolidated mine in Nevada> 
 which is said to have cost the stockholders $1,375,000 
 while the vendors received about $280,000, leaving 
 the promoters a clean profit of over a million dollars. 
 Luckily the mine repaid this enormous purchase price, 
 but had it nut, it would have been condemned as a 
 failure, when it was not legitimately entitled to be 
 saddled with so great a burden. This was strictly 
 gambling, not mining. The same thing has happened 
 in floating the mines of many other districts, and 
 notably so in the case of the Transvaal usually with 
 a less fortunate outcome. 
 
 A common cause of failure is in not keeping the 
 development of the mine ahead of its current 
 necessities. Such work will naturally reduce the 
 dividends for a time, but it is far preferable to pay 
 
INTRODUCTORY. 5 
 
 for these developments out of the profits of the mine, 
 while it is prosperous, than to have to raise an asess- 
 ment for the purpose when it is looking poor. Those 
 who have tried the latter plan know the attendant 
 difficulties, which are especially conspicuous in the 
 case of mines represented by unassessable stock. To 
 such mines an empty treasury means almost inevi- 
 table death, although a little medicine in the shape of 
 coin might give them a long lease of life. It always 
 happens that there are some stockholders who will 
 not advance any more capital, and the rest do not 
 feel inclined to do so and allow the non-payees to come 
 in and reap the benefits; while there is no way in 
 which undesirable partners like the non-paying stock- 
 holders can be got rid of, except by foreclosure of a 
 judgment for an indebtedness of the property. 
 
 Another frequent source of lost money is the erec- 
 tion of mills or other reduction works before they are 
 required. Nevada is full of illustrations of this kind 
 of folly, which is more apt to be committed by com- 
 panies than by individuals. In many cases magnifi- 
 cent mills were erected before the mine had been 
 opened even sufficiently to know if there was a mine 
 at all, and never dropped a stamp. Some of these enter- 
 prises were unmitigated swindles and seriously hurt 
 our mining interests abroad, so that the recovery of 
 confidence took years to complete. Not a few of these 
 mills were also utterly unsuited to the ore of the dis- 
 trict and were consequently valueless even for custom 
 use on the ore of other mines. In other cases the 
 mills have been too large for the property for which 
 they were erected, and it has been impossible to keep 
 them running steadily to their injury, as machinery 
 deteriorates rapidly from idleness. It would seem 
 that few miners have any idea of the amount of ore 
 which even a 10-stamp mill will consume in a year. 
 We often hear that a mine is ready for a mill, when it 
 has only a shaft from 50 to 100 ft. deep, or a tunnel of 
 
6 PROSPECTING AND VALUING MINES. 
 
 the same length. The absurdity of this proposition is 
 apparent. There may of course be instances where 
 the outcrop is so continuously in ore that there can be 
 no doubt of our ability to put the mine in shape for 
 extraction during the time consumed in the erection 
 of a mill, but this is quite exceptional. 
 
 Serious troubles have also arisen from false expecta- 
 tions based on small quantities of rich ore, or rather of 
 narrow seams. If these could be taken out by them- 
 selves they would often pay handsomely, even when 
 the quantities would not warrant the erection of a mill, 
 but as they cannot be extracted without removing a 
 large quantity of waste, the cost of doing this has to 
 be taken into consideration, as well as the difficulty of 
 preventing the loss of ore by mixture with the waste, 
 even when carefully hand-sorted. It is not intended 
 to intimate that these very small veins or seams may 
 not be worth working, for seams of very diminutive 
 thickness are worked at the mines at Nagyag in Tran- 
 sylvania; and in some cases, as the native silver mines 
 of Batopilas in Mexico, the sheet of ore is so tough 
 that when less than an inch in thickness it may be left 
 standing while the drift is run alongside, and stripped 
 down once a week or oftener, as may be desirable. The 
 object is to call attention to the frequent excessive cost 
 of working very narrow ore seams, that due allowance 
 may be made and failure avoided. 
 
 Want of knowledge of the structure of the deposit 
 is often a source of costly errors. It is not many 
 years ago that the writer saw a summer's work thrown 
 away by a superintendent losing the vein and not 
 knowing how to find it again. Starting on the vein 
 he apparently mistook the bedding of the rock for the 
 wall, as shown in pi. 6., fig. 2, and on reaching the 
 point B, where the ore apparently pinched out, went 
 off into the country rock along a small seam in the 
 hanging wall S. Not finding the large ore body which 
 was known by its outcrop to exist ahead of the tunnel, 
 
INTRODUCTORY. 7 
 
 he crosscut in the wrong direction at A toward (7, 
 when finding another small seam he turned back on 
 that toward the main vein again. Had he continued 
 on the line A C he would have come out to daylight 
 in a direction exactly opposite to that in which he 
 should have sought the ore body. The tunnel was 
 run in hard granite under very adverse circumstances, 
 entailing a serious outlay of money, which must be 
 charged against any future profits, because whatever 
 is spent on a mine ought to come out of it, and at the 
 end of the season's work the property w ? as in a less 
 satisfactory condition than before the tunnel was run ; 
 as many observers would naturally come to the con- 
 clusion that the mine was practically worthless, if the 
 ore seen on the surface was lost so promptly in depth. 
 (It has since been satisfactorily opened in the right 
 direction.) The same amount of money properly ex- 
 pended under judicious management would have taken 
 the tunnel through a body of ore which crops continu- 
 ously for several hundred feet, and would have been 
 extracting ore for its entire length, thus making a 
 profit instead of a loss, and putting the mine in shape 
 for stoping. 
 
 A most astonishing want of common sense in read- 
 ing the lesson of the outcrop has caused the loss of 
 much time and money. In the case of the mine shown 
 in pi. 12, fig. 5, the outcrop of the vein occupied 
 the fiat slope of a valley with a steep hill to the north, 
 and was scattered over a width of 100 ft. for a consid- 
 erable distance, but was not continuous, being broken 
 up into little patches of varying size. The ore was 
 rich, and being stained with the blue and green car- 
 bonates of copper, was very conspicuous by contrast 
 with the underlying yellowish limestones. Evidently 
 this was mistaken for the outcrop of an immense vein 
 or bed, but a very casual examination showed that the 
 vein was only a thin film between the slates S and 
 limestones L, for the little gulches running north to 
 
8 PROSPECTING AND VALUING MINES. 
 
 the main ravine had cut through the ore in numerous 
 places, in all cases revealing the underlying limestone, 
 and showing the true character of the deposit. That 
 it was not understood was proved by the company 
 running the tunnel Tto cut the vein. This was started 
 in the foot wall and beneath the seam, and naturally 
 never encountered ore. Had any further proof been 
 wanting, nature had furnished it, for at the eastern 
 end of the location, the bluffs (overlooking Death 
 Valley, Cal.) broke down perpendicularly for several 
 hundred feet, and had the vein been other than it was 
 it must have shown conspicuously on the face of these 
 precipices, which it did not. It would seem that this 
 idea had never occurred to the purchasers, who were 
 out of pocket on the transaction from $100,000 to 
 $150,000 in purchase money and working expenses, 
 while another mining failure was talked about and 
 nothing said of the folly of the investors and man- 
 agers, who would not believe the facts of the case even 
 when they had paid to find them out. 
 
 Again, it is only recently that a man professing to 
 be a mining engineer recommended the exploitation of 
 a bed of bog iron ore, when a casual investigation 
 showed that it was a deposit now forming, only a few 
 inches thick, limited to a few acres of marshy ground, 
 and did not show a few hundred feet to the westward, 
 where the ground breaks down abruptly in a bluff to 
 the seashore, consisting entirely of unconsolidated 
 sand and gravel. Investors in such a scheme would 
 have faced certain failure from the start, and would 
 unanimously have condemned mining as a business. 
 
 Another method of losing money is to sink or bore 
 for metals, coal or oil, or any other substance occur- 
 ring in beds or bedded veins, when nature has told 
 the whole story on the upturned edges of the rocks, 
 as shown in pi. 4, fig. 4, and pi. 3, fig. 5. In pi. 4, fig. 
 4, a shaft sunk at D would disclose no more informa- 
 tion than could be gained by walking over the country 
 
INTRODUCTORY 9 
 
 toward B, when tbe observer will pass over all the 
 rock strata which would be cut in the shaft, with an 
 immensely better opportunity of examining them in 
 detail and without cost. If there is anything of value 
 shown, as a coal seam at B, its merits can be discussed 
 before the expenditure of a dollar for underground 
 workings, and an incline could be sunk on it to greater 
 advantage than the vertical shaft Z>, at least until a 
 full knowledge of its character had been obtained. 
 This mistake has been repeated so often that every 
 person connected with mining must be able to recall 
 instances. The same might be said of a shaft at B, pi. 
 3, fig. 5, but at A } in the same figure, a shaft would 
 be excusable. In the neighborhood of Leadville, Colo., 
 the writer has seen a prospector sinking in the granite 
 to find carbonate of lead ore, which was an absolutely 
 hopeless undertaking, as can be seen by reference to 
 the cross section of the Leadville district, pi. 1, fig. 2, 
 where the granite and gneiss underlie everything arid 
 the ore is associated with the porphyry and limestone 
 beds above it. The utter improbability of success 
 would have been apparent to the prospector had he 
 possessed even a smattering of knowledge of rocks and 
 the occurrence of ore, but his shaft was another mem- 
 ber of the army of failures for want of that knowledge. 
 To him the proposition was plain that because others 
 had sunk shafts and found ore at varying depths, 
 without any surface showing, he had just as good a 
 chance as they. On the other hand the want of the 
 necessary preliminary exploration by boring, in the 
 case of coal fields especially (after the presence of coal 
 is known), may entail loss and failure owing to the 
 breaking up of the beds by faults, the presence of 
 which would have been made evident by a proper 
 series of borings in each direction. The beds might 
 not be ' 'faulted" or broken so regularly as in the 
 idealized cross section on pi. 1, fig. 1, which shows a 
 series of "step faults," but the figure will illustrate 
 
10 PROSPECTING AND VALUING MINKS. 
 
 the general idea. Let B, E, F and H represent bor- 
 ings. If only B and jEf have been made, the coal seam, 
 represented by the heavy black line, would have been 
 found in each, and its dip fairly ascertained, but no 
 indication of the faults A and B would have been de- 
 tected, unless the bore hole //had been carried down 
 some distance below the coal, and the works for the 
 extraction of coal, based on these borings alone, might 
 be valueless for working the bed between the faults B 
 and G. But if the borings had been extended over a 
 larger area and included others at E and F 9 the broken 
 nature of the formation would have been disclosed and 
 led to a thorough investigation as to whether the 
 locality could be profitably worked, and if not the cost 
 of permanent works would have been avoided. What 
 has been said of coal applies to many of the gold 
 gravel mines in California as well. 
 
 Even if the quantity and quality of the material, 
 such as coal, iron ore, clay and other minerals, which 
 come into severe competition with each other, and 
 require every facility in the way of cheap labor, cheap 
 transportation, and an extended market for successful 
 production, be all that can be asked, the deposits may 
 be so situated with regard to the latter requirements 
 that commercial failure must result from their explora- 
 tion. Andre, in his treatise on coal mining, p. 80, 
 puts the case very clearly : 
 
 "But if certain clearly apparent circumstances exist 
 which are sufficient of themselves to show that the 
 undertaking cannot be commercially successful, even 
 if all the other circumstances should prove favorable, 
 it is plain to ordinary common sense that it would be 
 sheer folly to prosecute a search which must necessarily 
 be an expensive one, and which must as necessarily 
 end in disappointment. Enormous sums of money 
 have been expended in this way to the great and mani- 
 fest injury of all legitimate enterprise." 
 
 Every mining man can undoubtedly recall numerous 
 
INTRODUCTORY. H 
 
 cases where labor has been expended on worthless 
 minerals which a very slight knowledge of mineralogy 
 would have saved. The writer has seen a shaft sunk 
 on a body of black obsidian (volcanic glass), under 
 the belief that it was anthracite coal. In another case 
 the men were prospecting for coal in a narrow canon 
 between basaltic walls, on the strength of a few pieces 
 of carbonized wood in the gravel beds filling the 
 gorge. In another instance several shafts were sunk 
 on a deposit of red jaspery clay, carrying specks of 
 iron pyrite, the prospector mistaking it for cinnabar 
 on account of its bright red color, having probably 
 heard that cinnabar was red, without knowing that 
 usually it assumed that brilliant tint only when 
 scratched or pulverized. For years a prospector in 
 Washington spent money on and clung to the idea 
 that he could develop an iron mine out of a body of 
 clay slate, mixed with quartz and large quantities of 
 iron pyrite, not knowing that the sulphur of the 
 pyrite was a most undesirable constituent in iron, 
 and that there was no probability of the deposit 
 changing its character. Then again tin is an ever- 
 recurring ignis fatuus. Recently the writer was 
 assured in perfect good faith by a person willing to 
 prove his faith by his works (if he could get some one 
 to join him), that he had pounded pure tin out of the 
 ore in a common mortar; and another could not be 
 convinced that the polishing of the mortar while 
 grinding so-called tin ore was not a coating of that 
 metal, the iron as he called it being "galvanized!" 
 Such stories lie at the bottom of many a newspaper 
 item, and hundreds of such wild-goose propositions 
 come before the mining engineer and mining men 
 generally every year. But many a prospector will 
 spend the best years of his life on such schemes, and 
 not infrequently drag his equally uninformed friends 
 into them, for want of a little knowledge so easily 
 obtained. 
 
12 PROSPECTING AND VALUING MINES. 
 
 Yet another common source of loss is the failure to 
 ascertain the true value of the ore and the probable 
 character and quantity before erecting expensive 
 hoisting and reduction works. Both of these subjects 
 are more fully treated of in Chapter II., and mention 
 of them is here made only to emphasize the impor- 
 tance of extreme care in all these points. Just as an 
 ounce of quicksilver if thoroughly mixed with a ton 
 of sand will show its presence in every pound of the 
 latter on washing, so a very small amount of free gold 
 will make a big showing in a ton of broken white 
 quartz. The writer has seen a dump on which free 
 gold could be easily found but which gave a return of 
 less than $5 per ton when milled. Coarse gold ores, 
 though the prettiest of specimens, are exceedingly 
 deceptive, and extreme caution is absolutely essential 
 to safety. Gold is so easily extracted from the ore 
 when native (free) that to ask for capital to develop 
 prospects reported to assay $50, $100 and upward per 
 ton is sure to excite suspicion in the minds of those 
 acquainted with the subject, as with a donkey, a little 
 water, a few pounds of quicksilver, and a fair share of 
 patience and physical strength the owner of such a 
 prospect can create his own capital, provided always 
 that the assay represents the whole mass and not some 
 individual specimen. 
 
 Costly mistakes are also made through want of 
 knowledge of the way in which ore is distributed 
 through the vein. Experience has taught the writer 
 that not a small proportion of those who might be sup- 
 posed to be somewhat familiar with the subject 
 imagine that a vein has a uniform thickness like a 
 plank, and like the latter is made up of the same 
 material throughout, so that there ought to be only 
 two kinds of veins, those which never carry ore and 
 those whicl} are continually in ore. Excessive antici- 
 pations and undue depression result from such views, 
 a diminution in thickness being never looked for on 
 
INTRODUCTORY. 13 
 
 the one band or an increased quantity on the other. 
 Probably no vein carries ore from wall to .wall through- 
 out its entire length. The probabilties are altogether 
 against such a condition. The spotted character of 
 most ore bodies is well shown in pi. 8, which is a 
 copy of a longitudinal section of the Dolcoath mine 
 (sometimes called Wheal Dolcoath) in Cornwall, Eng- 
 land. The length on the vein covered by the section 
 is about 3,300 ft. and the depth about 2,300 ft. The 
 longitudinal elevation of the Comstock lode prepared 
 by the writer for the U. S. Geological Survey shows 
 vastly greater blank spaces. A want of knowl- 
 edge of how ore occurs in veins has ruined many a 
 mine. Intimately connected with this subject, which 
 is treated at length when speaking of the structure of 
 veins, is the change in the character of ore in depth 
 from various causes, frequently resulting in the aban- 
 donment of the mine on reaching the water level. 
 Free gold ores may change into iron pyrites of a much 
 lower grade, yet more costly to work, and rich copper 
 ores may give out entirely, being replaced by low- 
 grade iron pyrite carrying a small percentage of copper 
 too lean to pay the cost of working. 
 
 Failure may also occur from want of care in protect- 
 ing the interior workings, resulting in extensive caves 
 which may involve the loss of a shaft or an entire ore 
 body by mixing it with waste from the walls and 
 reducing its value below the limit of profitable extrac- 
 tion. Even outside of coal mining such accidents are 
 far from infrequent. Only those who have seen the 
 evidence of the immense power developed by the pres- 
 sure of large masses of earth, or even by its expansion 
 under some circumstances, can realize its amount or 
 extent. Both in coal and gold gravel mining the floor 
 of a drift is apt to rise up or "creep," from the pres- 
 sure of the surrounding mass squeezing Jbhe bottom 
 upward into the space made vacant by the drift or 
 tunnel. This occurs especially when the floor is soft 
 
14 PROSPECTING AND VALUING MINES. 
 
 (or as the gravel miners say, "cheesy"). In one in- 
 stance in California the writer has seen a tunnel 
 driven through the rim, or bed rock of a gravel chan- 
 nel, as might be the lower tunnel in pi. 11, fig. 2, which, 
 when it broke through into the channel, encountered 
 a body of clay and gravel, so soft that it was squeezed 
 by the weight above into the tunnel like a huge sau- 
 sage, nearly as fast as it could be removed. In another 
 case of a tunnel being driven to reach some old work- 
 ings,the miners were furnished'with a grade-gauge by 
 which to lay the track, so that with one end laid upon 
 the older portion, the new sills could be put in as the 
 tunnel progressed, on the correct slope to connect 
 with the old workings. Owing to the creeping of the 
 bottom during the progress of the work, each set of 
 track timbers as it was laid was squeezed upward 
 before the time came to lay the following section, and 
 the tunnel came out much too high, and was a failure 
 in consequence of thus having acquired too steep a 
 grade. 
 
 Finally, litigation resulting from defective locations 
 is a fruitful source of trouble, involving a heavy tax. 
 on the resources of the mine. Through a forgetful- 
 ness of the importance of determining the direction of 
 lode before making the location it sometimes happens 
 that the lode passes out of the side lines into the prop- 
 erty of adjacent owners, instead of extending the full 
 length of the claim, and the mine not only loses a con- 
 siderable length of the lode, but becomes involved in 
 vexatious questions of boundary lines, the litigation 
 over which may absorb all the revenues or even leave 
 the mine in debt. 
 
 Such are some of the causes which lead to failure of 
 mining enterprises. They will be seen to be generally 
 due to want of knowledge on the part of the prospec- 
 tor, investor and managers of the enterprises of some 
 special point in their respective capacities. It must 
 not, however, be understood that all failures result 
 
INTRODUCTORY. 15 
 
 from this cause. There are cases where circumstances 
 arise which could not possibly be foreseen and guarded 
 against, and the judgment of the very best men may 
 err, for we are none of us infallible; but it is desired 
 to show that at least very great losses might be avoided 
 if there were a more general understanding and appre- 
 ciation of the fact that to be a successful mining man 
 requires a combination of mental and physical quali- 
 ties such as few other callings demand; and that min- 
 ing is a business calling for special training just as 
 certainly as technical knowledge is essential to the 
 watchmaker or shipbuilder. 
 
 The present chapter has been practically a presenta- 
 tion of failure after failure, and these would be often 
 laughable if the incidents were not so pathetic. The 
 good faith of the men who made the mistakes quoted 
 as samples was unquestionable, and only intensifies 
 the pity felt for their misdirected energies. Fortu- 
 nately there is a brighter side. The presentation has 
 only been made out of abundant precaution. There is 
 no more fascinating occupation in the world than min- 
 ing; none that keeps all the faculties so fully alive, 
 and no sensation so pleasant as the handling of the 
 bullion after a successful run ! while it is not unlikely 
 that the percentages of successes would prove as great 
 as in most of the other great industries. 
 
CHAPTER II. 
 WHAT CONSTITUTES A MINE. 
 
 A MERE bunch of ore will not make a mine; and it 
 may be well to examine the factors which really go to 
 constitute a mine. A "mine/ 5 then, is any deposit of 
 mineral which can be worked at a profit; that is to 
 say, before the deposit is exhausted it must have re- 
 turned to the "adventurers" (as the owners or operators 
 are frequently called in England) the original pur- 
 chase money, the entire cost of the improvements of 
 every nature, and the entire cost of working the ore, 
 whether it be mining, milling, smelting, transporta- 
 tion, supplies, superintendence, or office expenses, 
 together with a fair interest on the money invested. 
 If we charge against the salable product all the ex- 
 penses except purchase money and plant, we arrive 
 at the running cost of production per ton, and if the 
 selling price per ton be greater than this, the differ- 
 ence per ton will go to the account of purchase money, 
 development and plant; and there must be in the 
 deposit at least a sufficient number of tons of ore, 
 which, multiplied by the profit per ton, will extin- 
 guish the original cost of mine and improvements, it 
 being supposed that repairs to reduction or hoisting 
 works, etc., are charged to the cost of producing and 
 milling or smelting the ore. 
 
 For instance, if the purchase money and original 
 plant cost $200,000, and the profit per ton over ex- 
 penses of production and reduction is $10 per ton, the 
 mine must produce 20,000 tons,. at least, before it can 
 
WHAT CONSTITUTES A MINE. 17 
 
 be called self-sustaining, and a surplus over that 
 amount to cover reasonable interest. If the ore be 
 free gold quartz, or free-milling silver, about 13 cu. 
 ft. in place will weigh 1 ton of 2,000 lb., so that the 
 cubic contents of the 20,000 tons would be 260,000 
 cu. ft., equal to a block of ground 
 
 260 ft. deep by 1000 ft. long, if the vein be 1 ft. thick. 
 130 ft, deep by 1000 ft. long if the vein be 2 ft. thick. 
 65 ft. deep by 1000 f r. long, if the vein be 4 ft. thick. 
 
 or, if the ore deposit be only 500 ft. in length 
 
 520 ft. deep by 500 ft. long, if the vein be 1 ft. thick. 
 260 ft. deep by 500 ft. long, if the vein be 2 ft. thick. 
 130 ft. deep by 500 ft. long, if the vein be 4 ft. thick. 
 
 but if the ore shoot be only 100 ft. in length 
 
 2,600 ft. deep by 100 ft. long, if the vein be 1 ft. thick. 
 
 1,300 ft. deep by 100 ft. long, if the vein be 2 ft. thick. 
 
 650 ft. deep by 100 ft. long, if the vein be 4 ft. thick. 
 
 From the foregoing it is evident that the length of 
 the ore body is of immense importance, as the cost of 
 working a mine increases with depth at a constantly 
 increasing rate; and the longer the ore shoot, the 
 shallower will be the workings to accomplish the same 
 results. If the shoot be only 100 ft. long it will be 
 necessary to sink ten times as deep, at a heavy ex- 
 pense, as if it were 1,000 ft. Of course this is assum- 
 ing a theoretical regularity of deposit. 
 
 In order that similar calculations may be made on 
 other classes of ore, the following table gives the 
 specific gravity of the principal metals and their prin- 
 cipal ores; the weight of 1 cu. ft. of each, and the 
 number of cubic feet which will equal a ton of 2,000 
 lb. As the specific gravities of the ores are taken 
 from pure specimens, generally crystallized, they will 
 give, as a rule, quantities too small in the column of 
 cubic feet per ton, as the ores in run-of-mine are 
 seldom free from impurities; so that a somewhat 
 
18 
 
 PROSPECTING AND VALUING MINES. 
 
 greater number of feet should be assumed in making 
 the calculation, to be on the safe side: 
 
 SPECIFIC GRAVITIES OF METALS AND MINERALS. 
 
 Metals and Minerals. 
 
 Specific Gravity. 
 
 Weight of 
 cubic ft. 
 Pounds. 
 
 Number of 
 cubic feet 
 to ton. 
 
 Range. 
 
 Average. 
 
 Gold 
 Silver . 
 
 15.60-19.33 
 10.10-11.10 
 5.22-7.36 
 
 19.30 
 10.50 
 6.08 
 8.84 
 4.20 
 5.00 
 4.80 
 2.20 
 13.58 
 9.00 
 11.44 
 7.50 
 6.00 
 7.00 
 4.10 
 4.20 
 3.46 
 7.21 
 7.69 
 5.00 
 4.90 
 3.80 
 5.00 
 6.20 
 4.41 
 7.35 
 6.75 
 6.70 
 4.57 
 2.65 
 3.18 
 4.51 
 1.00 
 
 1206.25 
 656.25 
 380.00 
 552.50 
 262.50 
 312.50 
 300.00 
 137.50 
 846. (X) 
 562.50 
 715.00 
 468.75 
 375.00 
 437.50 
 256.25 
 252.00 
 216.25 
 450.00 
 480.00 
 312.50 
 306.25 
 237.50 
 312.50 
 387.50 
 275.62 
 459.00 
 421.87 
 418.00 
 285.62 
 165.62 
 198.75 
 281.87 
 62.50 
 
 1.66 
 3.05 
 5.26 
 3.62 
 7.62 
 6.40 
 6.66 
 14.62 
 2.36 
 3.55 
 2.80 
 4.27 
 5.33 
 4.57 
 7.84 
 7.95 
 9.25 
 4.44 
 4.17 
 6.40 
 6.53 
 8.42 
 6.40 
 5.16 
 7.25 
 4.35 
 4.74 
 4.78 
 7.00 
 12.08 
 10.06 
 7.01 
 32.90 
 
 Silver free ores 
 
 Copper 
 
 Copper pyrite 
 
 4.10-4.30 
 4.40-5.50 
 4.50-5.10 
 2.00-2.40 
 
 Copper purple 
 
 Copper gray 
 
 Copper silicate 
 
 
 CinnrJbar 
 
 9.00 
 
 Lead 
 
 Lead galena 
 
 7.257.70 
 5.40-6.47 
 
 Lead carbonate 
 
 Zinc 
 
 Zincblende 
 
 3.90-4.20 
 4.00-4.45 
 3.43-3.49 
 
 2jinc carbonate 
 
 Zinc silicate .... 
 
 Iron, cast 
 
 Iron wrought . . 
 
 
 Iron magnetite 
 
 
 Iron hema ti te 
 
 
 Iron limonite 
 
 
 Iron pyrite 
 
 4.83-5.20 
 6.00-6.40 
 4.32-4.49 
 
 Iron, arsenical pyrite.. 
 Iron chrome 
 
 Tin 
 
 Tin oxide 
 
 6.40-7.10 
 
 Antimony 
 
 Antimony sulphide 
 Quartz 
 
 4.52-4.62 
 
 Fluorspar 
 
 3 .01-3.25 
 4.30-4.72 
 
 Sulphate of baryta. .... 
 Water 
 
 But as we may frequently want the weight and bulk 
 of ores made up of several minerals, the following ex- 
 amples will show how the weight per cubic foot of such 
 ores may be obtained : 
 
 Calculation by Bulk. Take an ore containing say 
 50% of its bulk in galena, 25% in arsenical pyrite, 
 8% in zincblende, and 17% in quartz. By reference 
 to the foregoing table we have : 
 
WHA T CONSTITUTES A MINE. 19 
 
 0.50 of 1 cu. ft. of galena = 234.37 Ib. 
 
 0.25 of 1 cu. ft. of arsenical pyrite = 96.88 Ib. 
 
 0.08 of 1 cu. ft. of zinc blende = 20.50 Ib. 
 
 0.17 of 1 cu. ft. of quartz = 28.15 Ib. 
 
 1.00 379.801b. 
 
 Calculation by Weight. But if it be desired to 
 ascertain the weight of 1 cu. ft. of ore containing the 
 same minerals estimated by weight instead of bulk, we 
 can calculate the bulk of a known definite weight, say 
 1,000 Ib., and instantly determine the weight of 1 
 cu. ft. by simple proportion. Out of the 1,000 Ib. we 
 shall have : 
 
 500 Ib. galena -f- 468.75 = 1.068 cu. ft. 
 
 250 Ib. arsenical pyrite 387.50 = 0.645 cu. ft. 
 80 Ib. zincblende 4- 256.25 = 0.312 cu. ft. 
 
 170 Ib. quartz 165.62 - 1.026 cu. ft. 
 
 1000 3.051 cu. ft. - 
 
 or 6.102 ou. ft. per ton. By proportion the 
 
 Galena = 0.350 of 1 cu. ft. X 468.75 = 164.06 Ib. 
 
 Arsenical pyrite = 0.212 of 1 cu. ft. X 387.50 = 82.15 Ib. 
 
 Zincblende = 0.103 of 1 cu. ft. X 256.25 = 26.14 Ib. 
 
 Quartz = 0.336 of 1 cu. ft. X 165.62 = 55.65 Ib. 
 
 1.000 328.00 
 
 All other combinations may be worked out by these 
 examples. Assuming the profit on this class of ore to 
 be the same as that of tile free gold ore given pre- 
 viously ($10 per ton), it is clear that the ore body 
 would only have to be about half the dimensions before 
 quoted to secure the same results, as 1 ton only oc- 
 cupies about half the space of the first illustration. 
 
 Favorable Conditions. If the mine is so located 
 that its product can be sold to independent reduction 
 works, it is plain that smaller ore bodies may be profit- 
 ably extracted; and yet smaller ones if the mine be 
 worked by the original discoverers, and the ore is of a 
 grade high enough to yield a margin of profit over the 
 cost of extraction and transportation to market, as in 
 the first case there are no reduction works to be paid 
 for out of the profits of the mine, and in the latter 
 
20 PROSPECTING AND VALUING MINES. 
 
 case, neither reduction works nor purchase money. 
 Any ore body fulfilling these conditions may properly 
 be called a mine, and it is such that the prospector is 
 looking for. 
 
 Mining Compared with other Business. Only an 
 exceedingly small proportion of the locations made 
 ever develop into mines, probably not more than one 
 in a hundred. On the Comstock lode, out of several 
 thousand locations on record, less than fifty had any 
 large amount of development, and still fewer ever paid 
 dividends; yet the gross product of bullion from the 
 comparatively few active mines was enormous. Simi- 
 lar conditions hold good in most other mining camps; 
 but it is likely that the percentage of success in min- 
 ing enterprises is fully as great as in almost any other 
 line of business certainly as great if the same amount 
 of care has been exercised in selecting the property as 
 is usual in opening a new store or hotel. But the 
 miner must always remember that while the business 
 of the store may expand indefinitely, he is from the 
 very start living on his capital (the total amount of ore 
 in the mine), and that this diminishes daily the more 
 rapidly as the output is enlarged; while after reach- 
 ing its extreme productiveness the later stages of a 
 mine are merely like realizing on the assets of a fail- 
 ing business. 
 
 VALUATION OF MINING PROPERTY. The value of min- 
 ing property is therefore not to be estimated by the 
 amount of the dividends it may be paying at any par- 
 ticular time, but by the number and value of the divi- 
 dends it will be able to pay in the future. 
 
 Relation of Profits to Price. Thus, because a mine 
 has just paid an annual dividend of $1,000,000, 
 it does not follow that the mine is to be valued at 
 $10,000,000 (which would make the dividend equal to 
 10%), because it can only be worth that figure to pur- 
 chasers for investment if it is able to disburse that 
 amount or over in dividends in the future with a fair 
 
WHAT CONSTITUTES A MINE. 21 
 
 interest on the investment in addition. If the divi- 
 dends were distributed over ten years at the rate of 
 $1,000,000 per annum, the investors would just receive 
 the original amount paid without interest, so th&t if 
 the investors are to receive interest at the rate of 10% 
 on the money invested, the mine must pay another 
 $5,500,000 in dividends, making $15,500,000 in all, 
 to be worth $10,000,000 as an investment. 
 
 But it might be that the mine had reached its maxi- 
 mum productiveness when it paid the million-dollar 
 dividend, and the ore bodies in sight began to show 
 signs of exhaustion. In such a case the extreme value 
 to an investor would only be the actual profit on the 
 exposed reserves, which might be small. 
 
 The chance of finding new ore bodies cannot be 
 expressed in figures. One of the great sources of dis- 
 appointment in mining enterprises is the over-estima- 
 tion of mining values, mistaking capital for profit. 
 Another is the payment of unjustifiable prices, not 
 only for properties with considerable development, 
 but for holes in the ground or mere naked locations. 
 It is true that very often the purchaser expects to sell 
 again at a profit and not to work the property, but 
 then he has removed his dealings from mining to the 
 realms of speculation, and has no reason to grumble if 
 failure follows the change. 
 
 Ore "in Sight." Practically the value of a mining 
 location is the net profit on the ore exposed. If there 
 is any promise in the surroundings of a future to the 
 location, this definition might possibly be enlarged to 
 the gross value, the purchaser looking to developments 
 made with his own capital for reimbursement of the 
 original investment and profit. The value then of the 
 majority of original locations is very small. Many of 
 them are absolutely valueless, being made upon a mere 
 stain or a slight difference in the color of a certain 
 streak or layer of rock, or the presence of a little iron 
 pyrite in a particular seam, which only means that 
 
22 PROSPECTING AND VALUING MINES. 
 
 there has been decomposition of some of the horn- 
 blende or allied mineral contained therein. If, how- 
 ever, there is actually valuable ore in sight, this must 
 be carefully measured for length and breadth, and if 
 these measurements show a continuous workable body 
 the price of the location might possibly be the value 
 of this ore to a depth of a few feet, according to the 
 width of the ore exposed. 
 
 The situation is improved by the sinking of a shaft 
 or the running of a tunnel, but a single shaft does not 
 prove the existence of much ore. It simply shows its 
 presence at that particular point to a certain depth 
 and the quantity in sight will be the two triangles a 
 and b in pi. 13, fig. 1, multiplied by the average thick- 
 ness. If two shafts have been sunk, as in pi. 13, 
 fig. 2, we can call the shaded portion "in sight. " If 
 the development be a shaft with drift from the bottom, 
 as in pi. 13, fig. 3, we can still only consider in sight 
 the portion shaded, with a probability of more because 
 of the ore in the bottom of the drift c. The same will 
 be the case if a tunnel is run on the vein as B in pi. 
 13, fig. 4, but if the bottom of the shaft A is in ore 
 and the face of the tunnel B also, part of the block D 
 may be added to the probable reserves (unless the ore 
 is growing smaller in width), though it cannot be con- 
 sidered actually in sight, by which we understand a 
 block of ground exposed on all sides, as in pi. 13, fig. 
 5, where the blocks E E are actually in sight and 
 DDD can be added as probabilities, along with an 
 unknown quantity below the lower drift at F. In all 
 the foregoing examples it is supposed that the outcrop 
 is the extreme workable length of the ore, and that 
 none of the underground workings have been run out 
 of ore, so that we have no means of judging whether 
 the ore body is holding its own in size, or increasing 
 or diminishing; but if the explorations have developed 
 the facts shown in pi. 13, fig. 6, we can afford to be 
 liberal in the estimate of the probable reserves, as dis- 
 
WHAT CONSTITUTES A MINE. 23 
 
 fcinguished from ore in sight (shaded), because it is 
 evident that the ore body is not at present diminish- 
 ing in horizontal length, and may therefore be exten- 
 sive in depth. If, on the contrary, the result has been 
 as shown in pi. 13, tig. 7, we must be exceedingly con- 
 servative, as the ore body is evidently pinching out 
 downward as well as laterally. 
 
 It would be easy to extend these illustrations, but 
 enough has been said to show the basis on which esti- 
 mates of quantity of ore in sight in a mine are arrived 
 at, and also to show that work is the only thing which 
 can give value to a location. Because a prospector has 
 been able to make two or three locations or more, in a 
 season's work, it does not follow that they are actually 
 worth the time spent in securing them. The value of 
 an article is not the price paid for it, or its actual cost 
 to the owner. The price paid may have been out of 
 all proportion to the value, or the actual cost of the 
 article may have been so reduced by improved ma- 
 chinery that it can be bought for a mere fraction of 
 the Hum paid for the original production. So the 
 value of a mining property is not to be estimated by 
 what it has cost the parties offering it for sale, but by 
 the profit it will realize to the purchaser. 
 
 Grade of Ore. But even a large body of ore may be 
 valueless if the cost of extraction and reduction equal 
 or exceed the value of the metal extracted from the 
 ore; nor does it follow that, because ore of a certain 
 grade has been profitably worked in one mining camp, 
 this will hold good for all others, as the conditions 
 vary so widely. If everything in the shape of sur- 
 roundings is favorable, a very low-grade ore may prob- 
 ably yield a profit, while in another camp a much 
 richer ore may bring the miners into debt. 
 
 Sampling. Where no work has been done on a loca- 
 tion which shows enough of an outcrop to justify a 
 more extended examination, we can simply sample the 
 croppings thoroughly to ascertain which portions of 
 
24 PROSPECTING AND VALUING MINES. 
 
 them carry mineral enough to be valuable, and the 
 character of this mineral, because it is seldom that the 
 outcrop is of uniform value throughout its length. 
 This is not done by taking small hand samples here 
 and there, for the most honest man is not honest 
 enough to be able to select a fair average in such a 
 way. A clean cut across the entire width of the pay 
 streak should be taken at stated intervals, to avoid the 
 interference of the judgment, or the deception of the 
 eye, and each of these samples should be thoroughly 
 broken on a clean floor, mixed, spread out in a thin 
 sheet and quartered. One of these quarters should be 
 broken still finer, remixed and again quartered. This 
 will probably bring the sample down to such a size 
 that its entire mass can be ground to coarse "pulp. " 
 
 Assaying. From this pulp samples should be fur- 
 nished to two independent assayers, retaining the 
 balance for further tests should there be much differ- 
 ence between the results obtained from the assayers 
 (between whom there can be no collusion, as the look 
 of the pulp will not betray any peculiar external char- 
 acters of the ore by which its identity might have been 
 suspected). To furnish both assayers with the same 
 pulp is also fairer to the assayers, because they are both 
 placed on the same footing, which is not the case when 
 a piece of ore is broken into two pieces and one-half 
 given to each (except in a few exceptional cases), as 
 there may be sufficient difference in the composition 
 of the two pieces, especially in a complex ore, to war- 
 rant considerable discrepancies in the results obtained, 
 which would naturally throw a shadow of doubt upon 
 the entire investigation. In gold ores this is very 
 liable to be the case. A small sprinkling of telluride 
 of gold (looking like lead) might run one specimen up 
 into the thousands per ton and the other give only 
 tens. Care should be taken to distinguish between 
 mere specimens and true average samples. 
 
 In this way only can reliable results be obtained^ 
 
WHA T CONSTITUTES A MINE. 5 
 
 but if the ore prove to carry much gold, even then 
 they will not be entirely satisfactory, nor will they 
 indicate the true commercial value of the ore unless 
 determination of the nature and quantity of undesir- 
 able mineral constituents be made, if such are sus- 
 pected from examination of the ore as taken from the 
 vein. 
 
 When gold is found only in combination with other 
 minerals it is usually disseminated through them in 
 such fine particles that the distribution is compara- 
 tively uniform and an assay will be satisfactory, in so 
 far as the amount of gold in the ore is concerned; but 
 when a portion of the gold has become free, or liber- 
 ated from the associated minerals (as the various forms 
 of pyrites) by the decomposition of the latter, or still 
 more so when a portion of it has never been in com- 
 bination, but is scattered through the mass in particles 
 of varying dimensions, the assays will be in all prob- 
 ability valueless, because they may accidentally 
 include quite a large piece of gold (comparatively 
 speaking), and this multiplied by the thousands of 
 times which an assay sample is contained in a ton 
 would give very high results, while the next sample, 
 not containing such a piece, may only show very small 
 or insignificant returns. This may easily occur, as 
 the gold cannot readily be ground fine enough to pass 
 through the sieve with the other pulp, but must be 
 mixed with the pulp after it is ground, and thus the 
 chance of getting a fair average sample is exceedingly 
 small. 
 
 Horn Spoon. Every prospector should carry a horn 
 spoon, made by cutting off the belly of a large cow's 
 horn and polishing the inside with sandpaper, as in 
 pi. 13, fig. 8; or he can obtain an iron one of the same 
 shape, but having one-half galvanized to better show 
 black ore minerals. Such a spoon cau be carried in the 
 pocket, and if the presence of free gold in the ore be 
 suspected a few minutes will suffice to grind up a 
 
26 PROSPECTING AND VALUING MINES. 
 
 sample on a smooth flat rock with a small hand stone, 
 and wash it out in the nearest water hole, which can 
 be very much smaller than is required for the gold 
 pan, a bucket or even a wash basin being amply large 
 enough. The very finest colors may be detected by 
 this method. If any are found, a sample large enough 
 to secure a fair average should be taken, and the 
 entire mass reduced to pulp. All screenings which will 
 not pass through the sieve should be saved until the 
 process is complete, and then returned to the pulp, the 
 weight of which while dry should be carefulb r ascer- 
 tained. The pulp should then be mixed with water, 
 adding sufficient quicksilver to amalgamate the free 
 gold, and thoroughly worked over to insure complete 
 contact of all the gold with the mercury. The amal- 
 gam thus obtained may be reduced to a button with 
 the blowpipe, care being taken not to inhale the mer- 
 cury fumes, and then by simple proportion the amount 
 of free gold per ton may be ascertained with reason- 
 able accuracy, if the average of several tests be taken. 
 Thus, if 5 Ib. of ore contain 25c., 2,000 Ib. will contain 
 $100. 
 
 Segregating Ore Minerals. An assay of the pulp 
 which is left will give the amount of gold in combina- 
 tion with the "sulphurets" per ton, and the sum of 
 the two the total value of the ore. Also, by washing 
 out the sand the percentage of sulphides per ton of 
 ore may be ascertained, and an assay of these concen- 
 trated sulphides will give the value of the concentrates 
 per ton, and enable us to formulate a plan for their 
 reduction. But if the ore contains a number of min- 
 erals, such as iron pyrite, arsenical pyrite, zincblende 
 and galena, we cannot decide on the best method until 
 we have ascertained, by assay of pure samples of each 
 of these minerals separately, which it is that contains 
 the gold, or whether it occurs in all of them indis- 
 criminately. 
 
 In the case of smelting ores, such as galena com- 
 
WHAT CONSTITUTES A MINE. 27 
 
 bioed with zincblende, for instance, the presence of 
 the latter being detrimental to the process, it is espec- 
 ially desirable to know whether the blende carries any 
 appreciable amount of the precious metals contained 
 iu the ore, as the difference in the specific gravity of 
 the galena and blende is so great (7.5 to 4.1) that the 
 latter can be easily separated from the former during 
 the process of concentration, and if valueless except 
 as zinc, might be thrown away as a waste product, or 
 reserved for separate treatment if in sufficient quantity 
 to warrant such a course. 
 
 If the gold is largely in combination with iron 
 pyrite or other minerals which are easily decomposed 
 by exposure to the action of air and water, the out- 
 crop may yield a good showing of free gold in rusty 
 quartz, stained by the oxide of iron derived from the 
 pyrite, which may suddenly diminish in quantity 
 when the permanent water level of the mine is reached, 
 below which a large portion of the gold may be in 
 combination with the unaltered sulphides. Usually 
 such gold is very fine, almost if not quite like flour, 
 but occasionally, as in iron pyrite from the slates 
 near Fiddletown, Cal., the threads and crystals of gold 
 may be readily seen, and felt projecting from the 
 polished faces of the large cubes. 
 
 Special Cases. In the case of ores containing native 
 copper, the plan of taking a number of pounds and 
 working it in the same manner as free gold is the only 
 practicable way of getting fair results, and the same 
 remark applies to those carrying native or horn silver, 
 in fact to all ores containing minerals which will not 
 pulverize and pass through the sieve; but ordinary 
 assays are applicable to all other ores, provided care 
 has been taken in preparing the samples by having 
 them large enough and thoroughly mixed, so as to 
 secure average results. 
 
 Working Tests, Mill Runs, etc. As work pro- 
 gresses, the accuracy of the results first obtained may 
 
28 PROSPECTING AND VALUING MINES. 
 
 be tested to some extent by actual working methods. 
 The facility and cheapness with which this may be 
 done depend upon the nearness of reduction works of 
 a suitable character. High-grade ores can be shipped 
 over trails on mule-back, to works at long distances 
 from the mines, and even if the expenses consume all 
 the returns the experiment will be worth the cost; but 
 low-grade silver ores cannot be handled in this man- 
 ner. 
 
 Arastra. In the case of low-grade gold ores, in 
 which the gold is free, which will not bear transporta- 
 tion for long distances, good working results may be 
 obtained from an arastra built on the ground, as it 
 occupies only a small space and consumes but a small 
 amount of water. The arastra consists simply of a 
 circular floor made of large flat rocks carefully laid so 
 as not to leave crevices of too large a size between 
 them, inclosed by a low stone wall of suitable height, 
 say 2 to 3 ft. In the center is erected a vertical 
 spindle supported by a cross frame, to which spindle 
 is fastened a long horizontal shaft, and beneath the 
 latter cross arms to which large flat stones ("drags") 
 are fastened by means of short ropes or chains. When 
 a horse or mule is attached to the long shaft, and 
 driven round in a circle, the cross arms drag the rocks 
 attached to them around, and crush any ore which 
 may be fed into the machine between themselves and 
 the floor. Of course the amount worked daily will 
 depend on the size of the arastra, and the softness or 
 hardness of the ore, but it will do its work well and 
 give a fair working test. 
 
 Utility of Tests. By keeping the ore extracted from 
 each 10, 20, or 30 ft. of the shaft or tunnel by itself, 
 and working or shipping the batches separately, the 
 miner will soon learn which portion of the ore body is 
 the richest, and also whether it is fairly uniform in 
 value, or changes frequently within short distances. A 
 few such tests will soon determine the question 
 
WHAT CONSTITUTES A MINE. 29 
 
 whether it will pay to build a road to the mine, for 
 the cost of such a road will ultimately have to come 
 out of the mine. 
 
 Roads. Without roads no heavy machinery can be 
 gotten to 'the mine at anything like reasonable cost. 
 Mining roads are often very costly enterprises owing 
 to the rough and broken nature of the country which 
 they must traverse, and the want of them not infre- 
 quently greatly retards the development of otherwise 
 promising mining districts. As all the locations in a 
 new district must share equally in the benefits derived 
 from a main road placing them in ready communica- 
 tion with the outside world, the cost of the trunk road 
 should be raised by an assessment on each location, 
 made, by action of the mining laws of the district, a 
 requisite to a legal title to the location. The lateral 
 branches to the individual mines would naturally be 
 built by the mines at their own cost. A mine opened 
 by tunnels only will of course not feel the necessity of 
 roads so promptly and keenly as one which is com- 
 pelled by the nature of the ground to resort at once to 
 shaft-sinking, as the former will be able to get along; 
 with packages which need not exceed a mule-load in 
 weight, except in the article of timber, but all require 
 the roads sooner or later as a matter of economy even 
 in provisions and supplies. 
 
 PLANNING REDUCTION WORKS. Having then become 
 satisfied that the ore body is large enough and rich 
 enough to pay for its extraction, the character and 
 size of the reduction works remain to be determined. 
 
 Smelting. Should it be decided that the ore will be 
 best reduced by smelting, it is doubtful whether the 
 mine would be justified in erecting its own works, 
 unless it is situated where purchases of various other 
 ores can be readily made in considerable quantities, as 
 few mines produce ore which may not be worked to 
 greater advantage by admixture with other ores which 
 can supply its deficiencies without adding barren 
 
30 PROSPECTING AND VALUING MINES. 
 
 material to the charge in the furnace. Ores rich in 
 gold and silver, but poor in lead (usually called "dry" 
 ores), may require rich lead ores to flux properly ; or 
 ores with an excess of silica (quartz) may require the 
 addition of lime or iron-bearing ores to accomplish the 
 same result. It is from this circumstance that the 
 great smelting centers, such as Denver, Swansea, etc., 
 have arisen, which purchase everything which may be 
 offered, and mix and work the ores to the best advan- 
 tage ; each class of ore being kept separate in the yard. 
 A furnace charge may thus be made up from four or 
 five different kinds of ore, from widely separated locali- 
 ties, the more refractory ores being added in small 
 quantities .to those which work more readily. 
 
 Concentration. It often happens in a vein that on 
 one of the walls there may be a streak of solid mineral 
 suitable for shipment as it comes from the mine, with 
 no or only slight sorting, while the balance of the 
 vein is filled with material in which there is so much 
 waste as to render this impracticable; or the entire 
 vein may be of this character. 
 
 If the distance from the mine to the smelting works 
 is great, and especially if any considerable portion of 
 it be only trail or wagon road, it may not pay to send 
 these poorer ores, as the whole expense including trans- 
 portation might very likely more than equal the prod- 
 uct. Such ores must be dressed to better grade by 
 some method of concentration (usually by washing., 
 more rarely by air or magnetic separators) if the re- 
 sulting concentrates are rich enough to bear the cost 
 of transportation; otherwise they may be valueless 
 until the conditions of transportation are modified. 
 Concentrates consisting largely of galena or heavy sul- 
 phuretted silver ores may go to the smelter, but those 
 made up almost entirely of iron pyrites, such as are 
 obtained from many gold ores, may be retained at the 
 mine, and worked by chlorination, if the daily prod- 
 uct be large enough to keep a small reverberatory fur- 
 
WHAT CONSTITUTES A MINK. 31 
 
 nace for roasting in steady operation. These pyritous 
 ores may also be made into a commercial product by 
 matte smelting. 
 
 The capacity of the concentrator should be propor- 
 tioned to the output of the mine, just as the size of a 
 stamp mill is determined by the same factor, and this 
 output will depend on the size of the ore body and the 
 condition of the development. 
 
 Ore Supply Needed. -We frequently hear of a mine 
 being ready for a mill when it has nothing more than 
 a shaft 50 to 100 ft. deep, or a short tunnel on the vein. 
 As an approximation we may say that a mine should 
 produce 1 ton of ore daily for each of the men em- 
 ployed around it, including blacksmiths, carpenters, 
 carmen and outside help. There are of course mines 
 where better than this is done, but these are excep- 
 tional. We must therefore have room enough in the 
 mine for a considerable number of men to be engaged 
 in "stuping" ore and this involves a number of drifts 
 or stopes, even for a small mill. If very active develop- 
 ment is going on and the ground is easily worked, 
 there might possibly be sufficient ore extracted from 
 the face of the various headings, sinkings or upraises 
 to keep a small mill going; but to depend on these 
 would be bad policy, for the ore in several of them 
 might "pinch" at the same time, and shut the mill 
 down. Indeed, a mill should not be built until the 
 ore body has been so thoroughly explored that it may 
 be perfectly adapted to the requirements, both as 
 regards size and character of equipment, as although 
 it may be possible to find the money for experiments 
 or mistakes, they must all ultimately be paid for by 
 the mine and diminish the profits. 
 
 Calculation of Tonnage Mined. To enable the pros- 
 pector or miner to form a quick estimate of the 
 amount of ore which he may be extracting daily from 
 a drift, the following table will be found useful. 
 Three kinds of ore are given as types. First, prac- 
 
PROSPECTING AND VALUING MINES. 
 
 ideally clean galena; second, a concentrating ore; and 
 third, ordinary gold quartz ore or free-milling silver 
 ore, neither of which carry much heavy mineral. 
 The yield in pounds is for 1 running foot of a drift 7 ft. 
 high, and this figure multiplied by the number of feet 
 run daily will give the daily yield in pounds, provid- 
 ing there be no waste in saving the ore, as is usually 
 the case in small seams, which are difficult to take out 
 clean, especially if the ore is brittle or friable. 
 
 DAILY ORE EXTRACTION PER RUNNING FOOT J DRIFT 7 FT. 
 HIGH; VEIN VERTICAL. 
 
 Class. 
 
 Weight 
 per cubic 
 foot. 
 
 Thickness of Ore. 
 
 3 in. 
 
 6 in. 
 
 9 in. 
 
 1 ft. 
 
 2 ft. 
 
 3 ft. 
 
 4ft 
 
 1 
 
 469 
 '"328"' 
 
 820 
 0.41 
 574 
 0.29 
 290 
 0.16 
 
 1641 
 0.82 
 1148 
 0.57 
 581. 
 0.29 
 
 2461 
 1.23 
 1722 
 0.86 
 871 
 43 
 
 3283 
 1.64 
 2296 
 1.15 
 
 11.62 
 0.58 
 
 6566 
 3.28 
 4592 
 2.30 
 2424 
 1.16 
 
 9849 
 4.92 
 9888 
 3.44 
 3486 
 1.74 
 
 13132 Ibs. 
 6.56 tons 
 9184 Ibs. 
 4.59 tons 
 4648 Ibs. 
 2.32 tons 
 
 1 
 
 2 
 
 2 
 
 3 
 
 166 
 
 3 
 
 
 
 The principle used in this table may be applied also 
 to sinking shafts, thus: multiply the area of the work- 
 ing face (if all ore, otherwise the area of ore seam 
 only) by the number of feet sunk daily, and this by 
 the weight per cubic foot in the table. For instance 
 if we sink 3ft. daily on a 2-ft. vein and the shaft is 10 
 ft. long, then 10 X 2 X 3 X S28 = 60 cu - ft - X 328 
 = 9.84 tons, for ore of the second class; or if a drift 
 be 6 ft. high on a 2-ft. vein and we run 2 ft. daily, we 
 have 6 X 2 X 2 X 328 = 24 cu. ft. X 328 = 3.93 tons, 
 
 To assist also in forming an estimate of the most 
 desirable size for a null, the next table will be found 
 useful, being applicable also to the required capacity 
 of a concentrator. 
 
 The duty of a stamp varies greatly according to its 
 weight, the height of the drop and the number of 
 drops per minute, the hardness of the ore to be 
 
WHAT CONSTITUTES A MINE. 
 
 33 
 
 crushed, the fineness of the screen through which the 
 pulp must pass to escape from the battery, and the 
 height of the discharge. In the case of many gold 
 ores, in which the metal is very fine and the rock 
 hard, 1| tons per stamp may be a fair day's work (24 
 hrs.), but when the rock is softer, or the gold coarser, 
 it is not necessary to use so fine a mesh, and the dut3 T 
 may run up to 2 tons daily ; while if the working of 
 the ore is to be finished by grinding in pans, or the 
 ore is exceedingly soft, a mill may crush still coarser 
 and pass 2^ tons or over under each stamp in 24 hrs. 
 The table is therefore arranged for each of those three 
 capacities, and shows the amount of ore crushed an- 
 nually, its contents in cubic feet and the area of the 
 vein which would be extracted at various thickness. 
 It is based on the ordinary gold quartz or free-milling 
 silver ores (such as the ores of the Comstock), and 13 
 cu. ft. in the mine are considered to be a ton, as the 
 result of determinations made on that lode; and 300 
 days actual running time in the year. If the mill 
 runs more steadily the quantities must be proportion- 
 ately increased. 
 
 CAPACITY OF A 10-STAMP MILL. 
 
 Class Ore 
 
 ^ 
 J,* 1 
 
 il 
 
 Cubic ft. 
 per ton. 
 
 Equal blk. 
 Tons. 
 
 Consumption 
 per diem, 
 
 Consump. per annum 
 (300 days.) 
 
 t iN 
 
 tons. 
 
 2 
 
 tons. 
 
 2^ 
 tons. 
 
 titi 
 
 tons. 
 
 2 
 
 tons. 
 
 2^ tons. 
 
 1 
 
 165 
 
 13.0 
 
 1 
 
 15 
 195 
 30 
 195 
 
 20 
 260 
 40 
 260 
 
 25 
 325 
 50 
 325 
 
 4,500 
 58,500 
 9,000 
 58,500 
 
 6,000 
 78,000 
 12,000 
 78,000 
 
 7,500 Tons. 
 97,500 cu.ft. 
 15,000 Tons. 
 97,500 cu.ft. 
 
 1 
 
 2 
 
 328 
 
 6.5 
 
 2 
 
 2 
 
 
 
 
 AKEA OF VEIN EXTRACTED ANNUALLY. 
 
 Duty of Stamp. 
 
 Vein, 1 ft. 
 
 Vein, 2 ft. 
 
 Vein, 3 ft. 
 
 Vein, 4 ft. 
 
 Tons. 
 1U... 
 
 Ft. 
 
 585x100 
 
 Ft. 
 292x100 
 
 Ft. 
 
 195xiOO 
 
 Ft. 
 146x100 
 
 2 2 .:: 
 
 780x100 
 
 390x100 
 
 260x100 
 
 195x100 
 
 2V, 
 
 975x100 
 
 488x100 
 
 325x100 
 
 244x100 
 
 
 
 
 
 
34 PROSPECTING AND VALUING MINES. 
 
 The mixed ore is merely given as an illustration. 
 In fact, as a concentrating ore, it would more likely 
 be treated with rolls or other crushers than with 
 stamps, the object in concentration being to keep the 
 crushed ore in as large grains as possible, as the diffi- 
 culties of concentration and percentage of loss increase 
 with the fineness of the pulp. 
 
 The table itself requires but little comment. While 
 made up for only 10-stamps it can be modified to apply 
 to any desired number but it emphasizes very 
 strongly the desirability of long ore bodies, as it is 
 evident that to get a year's supply from a tunnel on a 
 vein 1 ft. wide, with a rise of the surface on the hill of 
 1 ft. in 2, we should have to follow the ore 484 ft. 
 into the hill, and upwards 242 ft. to the surface at the 
 end of the tunnel, as in pi. 13, fig. 9. If the ore 
 shoot were only 200 ft. long we should have to sink on 
 it or run another tunnel, either course involving an 
 extra amount of dead work. If 100 ft. long only, we 
 should have to sink 585 ft., attaining a depth of nearly 
 2,400 ft. in four years. If 200 ft. long, we should 
 sink 1,200 ft. in the same time. As the cost of sink- 
 ing and working m&in shafts is the heaviest item in 
 mining, the length of the shoot, as before stated, is all 
 important. 
 
 Backs. In no case should the outcrop be consid- 
 ered immediately available ore. About 50 ft. in 
 depth, or at any rate a sufficient thickness to avoid 
 caving, which will depend on the width of the vein 
 and the condition of the walls, should be left as a pro- 
 tection to the mine from surface water, for if the ore 
 be extracted it is sure to leave a depression into which 
 the snow and rainfall will drain, and find their way to 
 the lower workings, to be subsequently pumped out at 
 a heavy cost. These croppings will always remain an 
 available asset, and should be the last thing taken out 
 of the mine. 
 
 DEFINITION OF A "MINE." To sum up then, a mine 
 
WHAT CONSTITUTES A MINE. 35 
 
 is a body of ore of sufficient size and richness to repay 
 all costs of purchase money, erection of all necessary 
 plant, dead work, extraction, transportation and re- 
 duction, with good interest on the capital. Success 
 will depend largely on a thorough knowledge of the 
 sizo of the ore body as regards length, depth and 
 thickness; the true character and composition of the 
 ore; the adaptability of the hoisting and reduction 
 works to the requirements of the property ; careful 
 management by thoroughly competent men well up in 
 the business; avoidance of mistakes and experiments, 
 severe pruning of all unnecessary expenses, and the 
 treatment of the mine as a business undertaking, and 
 not as a gambling proposition. 
 
CHAPTER III. 
 ROCK-FORMING MINERALS AND ROCKS. 
 
 IT is not proposed to go further into this subject 
 than to furnish a condensed outline of the composi- 
 tion and structure of the principal kinds of rocks, 
 those most commonly met with in connection with 
 mineral deposits, so that the prospector may be able 
 to recognize the most important of them. To describe 
 all the different varieties would require a volume, and 
 would be of no special benefit in this connection, as 
 the distinctions are frequently founded on the pres- 
 ence of some minerals of difficult recognition and 
 quite secondary importance, and the descriptions 
 would necessitate a much more extensive knowledge 
 of mineralogy to make them intelligible than it is 
 necessary for a miner to possess. 
 
 ROCK-FORMING MINERALS. 
 
 The principal minerals which make up the bulk of 
 the rock formations are very few, and we shall find 
 that when able to recognize quartz (or silica), feldspar, 
 mica, hornblende and angite, there will not be much 
 difficulty in giving a rock a name. Some of these 
 names may really apply to groups of rocks, but in 
 such cases the name of the group will be close enough. 
 It is the different ways in which these five minerals 
 are combined that distinguish the igneous rocks from 
 each other; and it is the predominance of one or the 
 other in the secondarj' rocks (or those which have been 
 made out of the wear and tear of the igneous series) 
 
ROCK-FORMING MINERALS AND ROCKS. 37 
 
 which imparts to these secondary (or sedimentary) 
 rocks their peculiar characters. 
 
 Granite consists of quartz, feldspar and mica; sye- 
 nite, of crystallized fedspar and hornblende; and 
 basalt of feldspar and augite, with chrysolite or olivine, 
 so that with specimens of these three rocks before us, 
 or even in some cases with granite and basalt only, we 
 are ready to study the characters by which the min- 
 erals are to be recognized. The basalt used for refer- 
 ence should not be so fine-grained that its constituent 
 minerals are indistinguishable to the unassisted eye. 
 
 Quartz is the glassy portion of granite which cannot 
 be scratched with a knife. It crystallizes in the well- 
 known form, the separate crystals being always six- 
 sided prisms, terminating in a rather blunt pyramid 
 with six sides or faces; so that the description will be: 
 crystallizes in six-sided prisms (hexagonal) with six- 
 sided pyramid for a termination; color, sometimes 
 tinged with pale smoky or rose color, sometimes violet 
 as in the amethyst, usually colorless and transparent 
 or milky white; luster, vitreous (glassy); hardness, 
 cannot be scratched with a knife, and itself scratches 
 feldspar, glass, etc.; not acted on by sulphuric, nitric 
 or hydrochloric (muriatic) acids. 
 
 Feldspar is the white portion of granite which can 
 be scratched with a knife. There are numerous varie- 
 ties of feldspar, distinguished by their having either 
 soda, potash or lime as one of their constituents in 
 addition to the silica and alumina which are the essen- 
 tial ingredients, but it is not easy to give differences 
 which would be easily recognizable by the beginner 
 in the study. The crystallized forms are usually 
 white, more or less inclined to be transparent or trans- 
 lucent in new fractures, but often weathering to a 
 milky white. The feldspars in granites vary in color 
 from white through pink to dull red, and often occur 
 as seams of varying width running through the body 
 of the rock. These seams are inclined to break into 
 
38 PROSPECTING AND VALUING MINES. 
 
 squarish fragments, showing the tendency of the 
 crystals of this variety to have only four sides.- In 
 many of the porphyries almost the entire mass is 
 feldspar, the body of the rock being a kind of paste 
 of uncrystallized feldspar, colored various shades of 
 brown, green, pink, red, and purple, with scattered 
 crystals of white feldspar, or transparent quartz, im- 
 bedded in the paste, giving to it a spotted look. On 
 decomposition of rocks largely composed of feldspar 
 we have a series of clay formations, just as granites 
 yield sand and sandstones. 
 
 Mica is the mineral which in thin plates is often 
 wrongly called isinglass (which is fish glue). In color 
 it varies from colorless or white to black, through 
 various shades of gray, brown, yellow, green and 
 violet, the commonest colors being white, yellow, dark 
 brown, dark green and black. While sometimes 
 found in crystals of large size, they usually are quite 
 small. The crystals are flat, six-sided, and invariably 
 split into extremely thin plates parallel to the base of 
 the crystal. When broken across the crystal, as is 
 often the case in a rock fracture, the characteristic 
 six-sided form may not be visible, but the thin plates 
 separate easily into a brushy edge. These plates are 
 elastic and can be bent considerably without break- 
 ing, by which character the white varieties of the min- 
 eral can be distinguished from the crystallized varieties 
 of gypsum, which are also white and transparent and 
 split into thin plates or laminae, but are brittle and 
 break easily on bending. They are also destroyed by 
 the action of heat, whereas mica is practically infusi- 
 ble at ordinary temperatures, and is therefore used for 
 stove fronts, etc. When a rock is broken the crystals 
 may show with the flat side up, when they will appear 
 as in a, pi. 13, fig. 14, but if the fracture cuts through 
 the crystal the shape may be like b in the same figure, 
 the edges of the thin plates showing distinctly. The 
 colorless or white mica is called muscovite; the brown 
 or black variety, biotite. 
 
ROCK-FORMING MINERALS AND ROCKS. 39 
 
 Hornblende occurs usually in small crystals, gen- 
 erally black or greenish black. It is harder than mica 
 and does not split into thin layers, which fact can be 
 determined by the use of the knife. It very frequently 
 crystallizes in little square columns like a in pi. 13, 
 fig. 15, and sometimes in six-sided crystals, which 
 may, however, be easily distinguished from mica by 
 having two of the opposite sides much wider than the 
 others, as in 6, pi. 13, fig. 15. Hornblende is not 
 always crystallized. It often occurs in greenish or 
 blackish masses with a fibrous or radiated structure, 
 sometimes forming a rock almost by itself (horn- 
 blende rock) and grades down into asbestos, which, has 
 practically the same composition, and is only one of 
 the uncrystallized forms of hornblende, of which 
 there are many minor varieties, just as there are of 
 mica. 
 
 Augite is similar in appearance to hornblende, 
 except that the crystals in cross section show eight 
 sides, as in pi. 13, fig. 16, and is much less important 
 than hornblende to the student of rock composition, 
 until he has made some progress. We have thus 
 two usually pale or white minerals, and three dark 
 brown, ^greenish or black minerals to deal with, 
 and a very small amount of practice will enable 
 anybod.y to pick them out easily. The knife will 
 tell the difference between quartz and feldspar, 
 ' but mica, hornblende and augite are easily scratched 
 with the knife, giving a colorless streak, and the dif- 
 ference between the three minerals must be determined 
 by the shape of the crystals. 
 
 Many other minerals are associated with these, as 
 small grains of magnetic or titanic iron in granites, 
 forming the " black sand" of the miner; but they are not 
 essential constituents, except in a few cases. Garnets, 
 tourmaline, olivine, chlorite, chrysolite and apatite, 
 the last four all green minerals, may occur in small 
 grains or crystals, or may sometimes be so abundant 
 
40 PROSPECTING AND VALUING MINES. 
 
 as to give a distinct character to the rock, which may 
 then be called a "garnet rock," "chloritic slate/ 'etc., 
 as we shall notice later on. 
 
 KOCK STRUCTURE. 
 
 All rocks present lines of fracture, even though they 
 were deposited as a solid mass, but some present a 
 series of parallel planes along which they split with 
 great facility, sometimes along the lines of original 
 deposit, and sometimes nearly at right angles to the 
 former. These fissure lines are known as stratification 
 or lamination, cleavage and bedding planes, and it is 
 highly important that they should not be confounded. 
 
 Stratification is the result of earthy matter being 
 deposited in water as layer after layer, with intervals 
 of time between the deposition of the layers, during 
 which the first layer deposited had time to harden or 
 form a sort of crust which prevented it mixing freely 
 with the succeeding layer and so on; so that the mass 
 has become like a series of sheets of paper laid one upon 
 the other, and when converted into rock by the lapse 
 of time, and raised out of the water, the rocks split 
 easily along these lines of deposit. The layers may 
 vary greatly in thickness, depending on the amount of 
 sediment brought down by the stream and the length 
 of the flood periods. It is easy to understand that a 
 stream during flood will carry immense quantities of 
 matter into a lake or the ocean, becoming clear during 
 periods of drought, thus fulfilling the conditions called 
 for; and that such streams as the Mississippi, Amazon 
 and Ganges may form beds of vast extent, while others 
 may be limited to the area of a small lake. Eocks 
 formed in this manner are known as sedimentary or 
 stratified rocks. 
 
 Cleavage. Certain rocks, such as roofing slates, 
 while belonging to the stratified series, have become 
 so altered by pressure that they no longer split along 
 the lines of stratification or deposit, sometimes known 
 
ROCK-FORMING MINERALS AND ROCKS. 41 
 
 as "lamination lines" (a term applied to the thinner 
 strata), but on a series of joints which have been sub- 
 sequently formed by this pressure, generally more or 
 less at right angles to the lines of the original deposit. 
 The old lines of lamination are obliterated, and this 
 new series of joints is much more numerous than the 
 original horizontal planes, and the splitting character 
 much more perfect, dividing the rock into very thin 
 sheets. This structure is known as "cleavage. " It is 
 more or less developed in coal beds and is there known 
 as the * 'cleat," and is the cause of the coal breaking 
 into small pieces when mined. In crystals of minerals 
 the cleavage is the line on which the mineral splits 
 most readib r , and is usually parallel to one of the 
 smooth faces (facets) of the crystals. This is well 
 illustrated in mica and gypsum. 
 
 Bedding Planes and Strike Joints. In addition to 
 these splitting planes, all rocks (even limestone and 
 eruptive rocks) have acquired two or three sets of 
 joints, more or less at right angles to each other, 
 which divide the mass into large blocks and greatly 
 facilitate the labor of thequarryrnan, who takes advan- 
 tage of them in his mining operations. These may be 
 altogether independent of stratification, being the 
 result of the upheaval and compression of the earth's 
 crust, though in some cases they may follow some of 
 the more or less horizontal lines. Upon their char- 
 acter frequently depends the shape of mineral veins 
 and deposits. The joints which are roughly hori- 
 zontal, or parallel to the original stratification, are 
 called "bedding planes" or "dip joints," and the 
 series running with the general trend of the rocks 
 through the country, the "strike joints." These 
 joints may be very numerous or wide apart, and are 
 the cleanest cut in close fine-grained rocks such as 
 limestones, where they are not obscured by the stratifi- 
 cation planes, and also in some granites, furnishing 
 fragments of all sorts of angles. These joints may be 
 
42 PROSPECTING AND VALUING MINES. 
 
 only a few yards long, or may extend for a mile, the 
 latter feature being most prominent in close-grained 
 rocks which have suffered comparatively little dis- 
 turbance. A little thought will show why building 
 stones should be put into the structure in the same 
 position that they had in the quarry, that is, laid ac- 
 cording to their " bedding," being stronger in this way 
 than any other and less liable to scale off, on exposure 
 to frosts and the acids in the rain water of cities. 
 
 Metamorphixm. All rocks are constantly changing 
 their character. The mud banks of to-day will be the 
 shales and slates of the far future, and our sand banks, 
 the sandstones of a coming era. In the same way and 
 by the same agencies of time, moisture, pressure 
 and heat, many of the older sedimentary rocks have 
 lost much of their original character. The sand- 
 stones have become massive quartzites, in which 
 the small grains of quartz which compose the sand- 
 stone are no longer visible; and the slates and shales 
 have lost many of their lines of stratification, 
 besides suffering other changes which have imparted 
 to them a new common character, known as 
 "schistose. " Such rocks are called schists. It is 
 sometimes a very hard matter in a hand specimen of 
 these rocks to determine by the eye whether it belongs 
 to the metamorphic or eruptive series, so extensive have 
 been the changes, and only the microscope, or a dis- 
 tant view, when the main features of the mass alone 
 strike the eye, can settle the question. (When the 
 microscope is used in the determination of the rocks, a 
 flake of rock is ground down so fine that print can be 
 read through it, and it is this film that under the 
 microscope tells the story of its origin and composi- 
 tion). By reference to pi. 2, fig. 3, the difference be- 
 tween the structure of slates and schists will be better 
 understood* The upper part of the figure represents 
 a slate rock (let us say one in which there are numer- 
 ous fragments of hornblende by way of illustration, 
 
UOCK-FORMING MINERALS AND ROCKS. 43 
 
 otherwise a hornblende slate) and the lower part a 
 schist having the same composition, called a horn- 
 blende schist. In the latter there has been such are- 
 arrangement of the particles that though the mass 
 retains some traces of stratification, in the parallelism 
 of its bedding planes, it has lost the smooth lamination 
 planes, and consists of a series of plates, thickest in 
 the middle and thinning out all round like a flat lens, 
 the result being a very characteristic appearance 
 (known as "foliated''), in which only a few of the 
 lines of stratification have been preserved, although 
 the process has not been such as to produce clean-cut 
 cleavage. The result has in most cases been to 
 toughen the rock, felting the constituents together, 
 and few are more difficult to handle than this same 
 hornblende schist, as it will not split and is much less 
 brittle than most eruptive rocks. In these metamor- 
 phic groups the changes have usually been so great 
 that all traces of fossils have been destroyed, and their 
 geologic age can only be inferred from their associa- 
 tions. They are abundant in volcanic regions and 
 largely associated with mineral deposits. Their ulti- 
 mate condition when metamorphism is complete, ap- 
 pears to be a return to a rock in which all trace of its 
 sedimentary origin has disappeared and which cannot 
 be distinguished from those which we know to have 
 had an eruptive origin. The term metamorphism is 
 not applied to the simple hardening of muds into 
 slates, or similar processes, but only to those changes 
 in which a rearrangement of the particles has pro- 
 duced a rock with a decidedly differing appearance. 
 
 CLASSIFICATION OF HOCKS. 
 
 Rocks may be divided into simple and compound, 
 the first class including those which consist essentially 
 of one mineral, such as some limestones, gypsum, rock 
 salt, and serpentine; the second including those which 
 are made up of a combination of several dissimilar 
 minerals. 
 
44 PROSPECTING AND VALUING MINES. 
 
 The simple rocks resolve themselves into two groups, 
 the first of which consists of chemical precipitates, and 
 the second of organic structures. 
 
 The compound rocks resolve themselves into what 
 may be called the "original" group, consisting of 
 those of eruptive or volcanic origin, which are again 
 divided into the "plutonic" and "igneous" series, the 
 former term being applied to those rocks which have 
 been intruded from below without reaching the sur- 
 face, and the latter to those which have been ejected 
 as lava from volcanic vents; and the "secondary" 
 group, which is made up of rocks derived from the 
 wear and tear of all other rocks previously formed, 
 whether original or already secondary. This group 
 may be divided into the "stratified" rocks which have 
 been deposited in layers by the action of water, and 
 those which are the result of volcanic outbursts other 
 than lava, and which may be termed "fragmentary." 
 
 The stratified rocks are again devisible into the 
 simple and metamorphic sections. 
 
 The boundary lines between all these groups are very 
 poorly defined, and they can only be taken as gener- 
 alizations. Thus many limestones may contain so 
 much sand and clay, along with their fragments of 
 coral and sea shells, as to be almost a compound rock, 
 but they largely lack the stratified character, while in 
 the compound rocks many which have been ejected 
 from volcanoes also occur in situations where they 
 have obviously never been exposed to the atmosphere 
 at the time of their formation, as the basalts in the 
 coal beds. The following tabular presentation will 
 show the general arrangement in a compact form : 
 
 BOCKS CLASSED ACCORDING TO ORIGIN. 
 
 A. SIMPLE ROCKS. 
 
 I. Chemical Deposits such as some limestones, rock-salt, gypsum, 
 
 serpentine. 
 
 II. Organic Deposits such as some limestones, chalk, infusorial-earth, 
 coal, etc. 
 
ROCK-FORMING MINERALS AND ROCKS. 45 
 
 B. COMPOUND ROCKS. 
 I. Original group: 
 
 1. Plutonic series such as granite, syenite, etc. 
 
 2. Igneous series such as basalt, trachyte, etc. 
 II. Secondary group: 
 
 1. Stratified Rocks: 
 
 a. Simple such as shales, sandstones and conglomerates. 
 
 b. Metamorphic such as quartzite, soapstone, schists, etc. 
 8. Fragmentary Rocks such as breccias, volcanic tufas, and 
 
 glacial deposits. 
 
 SIMPLE BOOKS. As the limestones fall within the 
 limits of both the divisions of this class no attempt 
 will be made to treat the sections separately. Rock 
 salt and coal are very important commercially, but the 
 lime rocks from the great bulk of this series, either as 
 sulphates (gypsum) or, more commonly, as carbonates 
 (limestone, calcite). The great mass of limestone 
 has been segregated from sea water, into which it has 
 been carried by the streams which have dissolved it 
 from the rocks through which their waters have per- 
 colated. 
 
 Limestones proper vary in hardness from very soft 
 to quite hard rocks, compact and usually close-grained 
 in structure, ranging in color from white through 
 shades of yellow and drab, to blue and even black, and 
 consist essentially of carbonate of lime, which effer- 
 vesces on the application of acids; and they may con- 
 tain so many impurities, such as clay, sand, etc., that 
 they become unsuitable for the manufacture of quick- 
 lime for building purposes. This arises from the 
 varying conditions under which they have been 
 formed, and which determine their character. A large 
 portion of them consist of the rocky skeletons of corals 
 or the shells of minute animalcules. 
 
 Chalk consists of the minute shells of a vast group 
 of small animals called Foraminifera, which live in 
 sea water in countless millions. These extract the 
 carbonate of lime, which forms their shells, from the 
 sea water, and when dead they fall to the bottom 
 forming a soft ooze, which if exposed to view in future 
 ages would be the same as chalk as we know it. These 
 
46 PROSPECTING AND VALUING MINES. 
 
 shells are so minute that only a powerful microscope 
 can show their forms, and it takes millions of them to 
 form a cubic inch of rock. The purer forms of chalk 
 are soft, white and earthy, but time has wrought such 
 changes that some of its varieties become more and 
 more compact, until they grade into limestones, and 
 the organic formations have had their constituents so 
 modified that nearly all trace of their organic origin 
 has disappeared, and they can scarcely be distin- 
 guished from the granular crystalline chemical 
 deposits. 
 
 Flint, which is a form of silica, occurs in the chalk 
 beds, and has probably been formed by the separation 
 of small quantities of silica from some of the organic 
 remains, by percolating waters, and its concentration 
 into rough nodules of very compc^ct structure, usually 
 dark or blackish in color, and resembling horn or 
 glass in thin fragments. 
 
 Coralline Limestones. Immense deposits of lime- 
 stona have been built up by coral insects, like the reefs 
 so common in the warmer seas of the world at present, 
 and these usually contain numerous fossils which stand 
 out more or less prominently on the surfaces of the 
 rock which have been weathered by the action of air 
 and water, though they may be indistinguishable on a 
 freshly broken surface. This probably arises fom the 
 greater solubility of the uncrystallized portions of the 
 rock. 
 
 Other deposits have been made up of broken frag- 
 ments of coral detached from the main reef, and 
 washed upon the adjacent beach, where they have 
 been mixed with sand and broken sea shells,forming 
 beds with many impurities. 
 
 Besides these, there are compact beds which appear 
 to have been chemically deposited. To this section 
 also belong those deposits made by hot springs which 
 deposit the excess of lime held in solution on cooling 
 as "sinter," a term applied to all such formations, 
 
ROCK-FORMING MINERALS AND ROCKS. ^ 
 
 whether formed of lime or silica. If made of the 
 former, they are known as <( calcareous sinter/' if of 
 the latter as "silicious sinter." 
 
 Limestones for making quicklime should be free 
 from silica. When this is present in considerable 
 quantities, it not infrequently makes itself visible on 
 the weathered surfaces, imparting to them a peculiar 
 dry harsh feel, the lime wearing away more rapidly 
 than the silicious portion, which is thus left in relief 
 on the exposed surfaces. These silicious limestones 
 and those carrying clay or alumina, which are not 
 suitable for the production of ordinary lime, are util- 
 ized in the manufacture of hydraulic cements. 
 
 Marble is a variety of limestone in which the entire 
 mass has become highly crystalline. The finest varie- 
 ties are as clear and even in grain as lump sugar. In 
 colors there is an infinite variety, many kinds being 
 often found in the same belt. Freedom from iron min- 
 erals (which will rust and stain the dressed slabs), 
 purity of color and closeness of grain are the chief 
 elements in determining the value of marble, but cheap 
 transportation to market is essential to the successful 
 opening of a quarry, however good the stone may be. 
 
 Dolomite is a magn-esian limestone, consisting of the 
 carbonates of lime and magnesia, usually of a crystal- 
 ine texture and yellowish tints ; and while some bodies 
 appear to be original chemical precipitates, others are 
 undoubtedly ordinary limestones which have been 
 changed by the percolation of magnesian waters. 
 Both the ordinary carbonate ol lime and the magne- 
 sian variety are used as fiuxes in the smelting of iron 
 and lead, but all limestones are not of equal value for 
 this purpose, any more than they are for quicklime. 
 A chemical analysis or practical test must determine 
 their value for both purposes. 
 
 Magnesite in composed of carbonate of magnesia, 
 and is much less common than limestone or dolomite. 
 
 Limestone crystals (calcite, calcspar) are often mis- 
 
48 PROSPECTING AND VALUING MINES. 
 
 taken for quartz, and as it is a frequent accompani- 
 ment of metallic ores, the chief differences are worth 
 noting. In crystallized limestone the characteristic 
 shape is rhomboidal ; that is, the crystals are four- 
 sided, but none of the angles are right angles, while 
 each pair of sides is parallel. When crystallized in 
 pointed forms with six sides, the crystals are like 
 pyramids, without the straight portion seen in quartz, 
 and the apex is more pointed. This sharp-pointed 
 character has given it the name of "dogtooth spar. " 
 In addition to these differences it is much softer than 
 quartz, being easily scratched by the knife, and splits 
 easily along the line of cleavage. Carbonate of lime 
 (calcite) is not likely to be mistaken for any other 
 mineral than quartz except feldspar and gypsum, and 
 from these it may be distinguished by the action of 
 acids, or by the fire test to ascertain if it will form 
 quicklime. This will set slowly, whereas burnt 
 gypsum forms plaster of paris and sets promptly when 
 mixed with water, but does not become as hard as the 
 cements made by calcining silicions limestones. 
 
 Gypsum (sulphate of lime) differs from the carbo- 
 nate in that it does not effervesce with acids. It is 
 valuable chiefly as the source of plaster of paris and as 
 a manure, the latter consisting simply of the raw pul- 
 verized rock. Gypsum crystallizes in white translu- 
 cent masses which scratch very easily and split into 
 thin non-elastic flakes, which may sometimes be ob- 
 tained of great size; this form is known as 
 
 Selinite. Fibrous, very silky varieties of gypsum 
 are known as "satin spar;" and the close-grained 
 forms, when of even texture and finely crystalline, are 
 distinguished as "alabaster," 
 
 Infusorial earth resembles chalk in appearance and 
 general constitution, being made up of the skeletons 
 or shells of minute organisms, but the term is gener- 
 ally applied to those which consist of the scales of 
 little vegetable organisms called "diatoms." These 
 
ROCK-FORMING MINERALS AND ROGK8. 49 
 
 are made of silica instead of lime, and consequently 
 the rock is not acted on by acids. The excessive fine- 
 ness of the powder derived from crushing these earths, 
 and the hardness of the individual particles, make 
 them very useful for polishing powders, which are 
 known commercially as "tripoli," "electro silicon," 
 etc. 
 
 Serpentine is essentially a hydrated silicate of mag- 
 nesia, and is a dark blackish-green rock, with very 
 smooth slippery joints, generally highly polished and 
 variegated with greenish or yellowish films, like soap- 
 stone or French chalk such as is used by tailors. The 
 more brilliantly colored varieties are used for orna- 
 mental stonework, under the French name of "verde 
 antique." While. some serpentines have been original 
 deposits on the sea floor, others have been in all prob- 
 ability intruded masses of eruptive rock, containing 
 olivine, which have undergone extensive metamor- 
 phism and assumed their present aspect. 
 
 COMPOUND BOCKS, ORIGINAL GROUP. Instead of de- 
 scribing these rocks under the two series named in 
 the table, which is based on their origin, and often 
 calls for extended investigation to determine to which 
 series any particular rock should be referred, it will 
 be sufficient to here classify them by some striking 
 physical peculiarity which is easily recognizable by 
 everybody. 
 
 Three distinct forms may be recognized: (1) Those 
 which are entirely crystalline, or made up of a mass of 
 crystals each of which is distinct; (2) those in which 
 a certain portion of the crystals are scattered through 
 a "paste" of feldspar, which is very compact and does 
 not show any distinct structure; and (%) those which 
 do not show any signs of crystallization, but are of the 
 same character throughout. 
 
 It must be understood that this arrangement is 
 purely arbitrary, as it separates closely allied forms; 
 but it possesses the great advantage of being appli- 
 
50 PROSPECTING AND VALUING MINES. 
 
 cable without the use of the microscope, which is es- 
 sential to any scientific classification. In this place 
 the object is simply to enable the miner to find out 
 the approximate name of any particular rock with the 
 smallest amount of trouble, and not to educate him 
 for an expert petrologist. Only the most characteris- 
 tic of these rocks will be described. 
 
 In the crystalline rocks the size of the crystals does 
 not change the name of the rock. The size of the 
 crystals may be said to merely indicate the rate at 
 which the mass of rock cooled, and the amount of pres- 
 sure under which the cooling took place. If an 
 ejected lava cools very rapidly there is no time for the 
 particles to arrange themselves in any particular man- 
 ner, and the product is a rock which has all the ap- 
 pearance of the slag from a smelting furnace. If the 
 rate of cooling has been slower we have a crystalline 
 rock in which the separate crystals are small; and if 
 the cooling has been excessively slow we may have 
 large and well-defined crystals, there having been 
 ample time for a complete arrangement of all the con- 
 tents of the rock into their respective kinds, according 
 to the proportions of the various constituents and 
 their relative affinities. "While this may be stated as a 
 general proposition, it must not be taken as an abso- 
 lute rule, as it may be varied by the more or less easy 
 fusibility of the different minerals varying the proc- 
 ess. These rocks vary greatly in their mode of forma- 
 tion, though they all agree in their comparatively 
 deep-seated origin. As they are intimately connected 
 with the great changes in the earth's crust, and prob- 
 ably owe their fusion to the heat developed by the 
 immense pressure and friction incident to these 
 changes (and perhaps by chemical action), it is not 
 surprising that we find them chiefly in those localities 
 where these changes are most activeb r at work, namely 
 in the great mountain ranges. They may be found as 
 great bosses or as dikes which have been squeezed into 
 
-HOCK-FORMING MINERALS AND ROCKS. 51 
 
 the rocks from below while in a plastic or semi-fluid 
 condition, as in the case of some granites (pi. 5, fig. 
 5) or of the trachytes shown in pi. 5, figs. 1, 2 and 4. 
 In the latter case the force exerted was not sufficient 
 to break through the crust of overlying rock, but was 
 sufficient to lift a portion of the surface into the form 
 of a dome, the space thus formed being filled with the 
 molten rock, a portion of which through smaller vents 
 found its way in the horizontal layers of the sedi- 
 mentary rock, forming beds between them, just as the 
 basalt lava has found its way into coal seams, as 
 shown in pi. 5, fig. 6, and between the shales as in pi. 
 5, fig. 3. In these figures No. 4 shows the theoretical 
 structure of such a lava mass, showing the pipe a 
 through which the lava (black) was seeking an outlet, 
 and the lava forming a solid mass with branches pene- 
 trating the overlying strata, and forming thin beds 
 between them. In fig. 1 we have the top of such a 
 mass exposed in the side of a canon, of which a b is 
 the bed, with the strata (partially worn away) curving 
 over the solid lava; while in fig. 2 we have an actual 
 cross section through a mountain formed out of such 
 a block, the solid lines showing what remains in place, 
 and the dotted lines the original shape of the portion 
 which has been removed, a being the bed on which the 
 lava (black) spreads out, and b the shales, between 
 the layers of which thin sheets of lava found a lodg- 
 ment, as shown by the alternating outcrop of c, c. In 
 'fig. 3 we have similar horizontal beds of lava c, pene- 
 trating the strata as offshoots from the dike d, but the 
 lava at c is evidently only the remains of a similar 
 sheet from which the superincumbent strata have been 
 worn away, and not an outflow in the open air, because 
 remains of other lava sheets are found above other 
 strata at higher levels, as at e. In fig. 6, a, a, are 
 shales, b coal, and c basalt, the latter intruded into 
 the coal bed through the dikes d, d. In this case the 
 coal is destroyed and the lava, originally black, has 
 
52 PROSPECTING AND VALUING MINES. 
 
 been altered to a whitish rock by the action of the 
 coal on the cooling lava. 
 
 In other cases the lava has forced its way to the sur- 
 face, through the fissured rocks, and overflowed from 
 the dike in immense sheets, or has been ejected from 
 volcanic cones in huge streams, which have traveled 
 many miles, filling up valleys and even continuing 
 their course under the sea. Similar eruptions take 
 place on the sea floor. Volcanic eruptions are also fre- 
 quently accompanied by the formation of vast fissures 
 on the flanks of the mountain which become filled with 
 lava, and all these exhibitions of deep-seated heat pro- 
 duce profound changes in the rocks which they 
 traverse, the heat of lava streams being preserved for 
 many years after all volcanic activity has ceased, so 
 slowly do they cool when once crusted over. 
 
 It is thus evident that the same body of lava may 
 cool under very different conditions, and these have 
 more or less effect on the appearance of the rock, so that 
 the determination of the different kinds is often a 
 matter of difficulty even to experts. 
 
 ORIGINAL COMPOUND ROCKS, FIRST GROUP (wholly 
 crystalline). Adopting the simplest though arbitrary 
 classification for the sake of convenience, and disre- 
 garding for the present purpose differences of origin, 
 the compound "original" rocks (including both plu- 
 tonic and eruptive rocks) of the first group embrace 
 such species as granite, syenite, felsite, elvanite, 
 trachyte, basalt, etc. 
 
 Granite is a mixture of quartz, feldspar and mica. 
 It may be either fine-grained or coarse, and vary in 
 color according to the color of some one of its constit- 
 uents. If the mica is white, we have a nearly white 
 or light-colored granite; pink and red granites take 
 their color and names from the tint of the feldspar, 
 just as very dark or even black granite results from 
 the abundance of black mica. When the feldspar is 
 white and mica black in moderate quantities we have 
 
HOCK-FORMING MINERALS AND ROCKS. 53 
 
 various tints of gray. It is often traversed by dikes 
 of younger age, usually paler in color and more com- 
 pact than the rock which they cut; and though called 
 the oldest rock, it is frequently found as veins (con- 
 nected with the main mass) which penetrate both the 
 stratified and unstratified rocks above it (as shown in 
 pi. -5, fig. 5), which are usually much altered thereby. 
 Granite belongs to the group of rocks called "plu- 
 tonic," which have not broken through the surface of 
 the earth's crust, but have consolidated at some depth 
 beneath it. Sometimes hornblende is present in small 
 quantities along with the mica, when it may be termed 
 hornblendic granite, on the principle of using as a 
 descriptive adjective the name of any peculiar mineral 
 present in a rock but not essential to its composition. 
 
 Granite seems to be the underlying rock of the 
 entire series, and if this be the case it is not strange 
 that all the rocks which have been derived from it 
 should show a tendency to return to it, in appearance 
 and composition, during the lapse of time, through 
 the agencies of heat and pressure. 
 
 Felsite, felsite-porphyry and elvanite are crystalline 
 mixtures of quartz and feldspar, usually so intimately 
 mixed that in felsite the crystallization is scarcely vis- 
 ible, while elvanite is more distinctly granular. The 
 latter rock is of frequent occurrence in the mining dis- 
 tricts of Cornwall, and the dikes of it are known by 
 the miners as"elvans," from which term the scientific 
 name of the rock has been derived. 
 
 Trachyte and Rhyolite. In many respects trachyte 
 resembles granite, but may be easily separated by the 
 feel of a fresh fracture, which is exceedingly sharp and 
 rough, suggesting the surface of a cat's tongue. It 
 occurs as dikes and large eruptive overflows, belong- 
 ing to the series of modern lavas. In color the rock 
 has a wide range of variation from gray to pink and 
 brown. In composition the feldspar predominates 
 over the quartz and is usually accompanied by horn- 
 
54 PROSPECTING AND VALUING MINES, 
 
 blende, mica or augite. It may be considered the 
 modern equivalent of the older granite, but differing 
 from the latter in being a volcanic product. Ehyolite 
 is another rock so closely related to trachyte that the 
 beginner will find it hard to separate them. As the 
 mode of occurrence and general associations are 
 entirely similar to trachytes, the distinction is not of 
 essential consequence 
 
 Syenite, The foregoing rocks have quartz as an 
 essential constituent, while in syenite and basalt it is 
 absent as free or visible quartz, or nearly so. For- 
 merly syenite was considered a crystalline mixture of 
 quartz, feldspar and hornblende, but the term is now 
 used for a rock made up of crystalline feldspar and 
 hornblende, with mica as an accessory or accidental 
 mineral. In appearance it strongly resembles granite 
 (but the knife will show the absence of quartz), and 
 occurs in much the same way. The feldspar has a 
 different composition from that found in granite. 
 
 Basalt is the last of the wholly crystalline series 
 which need be noticed here. It is usually a very dark, 
 blackish, fine-grained rock, consisting of feldspar and 
 augite, with a variety of associated minerals, such as 
 olivine, occurring as small olive-green grains, of which 
 the oxides of iron and manganese form about 15% of 
 the mass, making the rock unusually heavy (sp. gr., 
 2.95). It has been ejected from modern volcanoes in 
 immense quantities, covering hundreds of square 
 miles in the States of Washington and Oregon, the suc- 
 cessive eruptions or overflows from dikes forming a 
 series of layers, resembling strata, and having in the 
 aggregate an immense thickness. It is also the rock 
 now being ejected by the volcanoes in the Hawaiian 
 Islands, and, from its fluid character when molten, 
 forms perfect rivers. It was such lava streams which 
 filled the mountain-valleys of California and covered 
 the gold-bearing gravels during the second outbreak, 
 as the trachytes had previously done at a much earlier 
 
ROCK-FORMING MINERALS AND ROCKS. 55 
 
 period. When cooled rapidly, as on the surface of a 
 new outbreak, it becomes full of bubbles formed by 
 the expansion of the steam contained in the lava (to 
 which it owes its fluidity), and it is in these cavities 
 that opals, calcite and similar minerals have been 
 formed by percolating waters. The porous lavas, with 
 the bubbles so filled, are known as amygdaloids (from 
 a word meaning almond). Below the surface the pres- 
 sure has prevented the expansion of the steam so per- 
 fectly, so that the bubbles get smaller and smaller till 
 the mass becomes perfectly crystalline. Very fluid 
 lavas may be so filled with these air, gas, or steam 
 cavities that they look spongy and will float on water 
 as "pumice stone, " or they may be drawn out by the 
 violent winds eddying round the crater into fine 
 threads like spun glass, in which form they are known 
 as "Pele's hair, " Pele being a goddess associated with 
 the Hawaiian volcanoes. Basalt frequently crystallizes 
 into a columnar structure, the pillars being five or six- 
 sided, with ball-and-socket joints. This columnar 
 structure is always at right angles to the sheet of lava, 
 so that in dikes they form more or less horizontally from 
 wall to wall, and in overflows more perpendicularly. 
 
 SECOND GROUP (porphyritic). In this group we 
 have quartz-porphyrj r and a whole series of other por- 
 phyries in which visible quartz ^is absent and which 
 for the purposes of the miner we may designate simply 
 as '"porphyry," using the term as a general one. 
 
 Quartz-porphyry or dacite consists of a paste of 
 feldspar which shows no sign of crystalline structure, 
 the color of which may range from dirty white to pink, 
 purple, brown or slate-graj'. In this paste are scat- 
 tered small grains of transparent quartz, making a 
 very characteristic rock which occurs in large masses, 
 the rock belonging to the series of old lavas. It is 
 largely developed in the Comstock mining region. 
 
 Porphyry. Under this head may be classed all the 
 rocks in which the paste just described contains dis- 
 
56 PROSPECTING AND VALUING MINES. 
 
 tinct crystals of feldspar, giving them a spotted appear- 
 ance. They may contain mica, hornblende or augite 
 as an additional mineral, and it is the presence of 
 these,alorig with differences in the composition of the 
 feldspars, which constitutes the basis for a new name. 
 
 They occur as dikes, veins, intruded sheets, or as 
 surface deposits, and include such species as porphy- 
 rite, diorite or greenstone, andesite, phonolite or 
 clinkstone, etc. 
 
 THIRD GROUP (non-crystalline). In this group we 
 have pumice stone, already described, and as the prin- 
 cipal rock 
 
 Obsidian, which is a lava cooled very rapidly, look- 
 ing like coarse bottle glass, and hence frequently 
 called ''volcanic glass/' It is of various shades in 
 greenish black, black or red, and the red varieties are 
 sometimes marbled with black streaks which are drawn 
 out in the direction of the flow of the lava stream 
 while 3'et in a pasty condition. 
 
 It is not pretended that the foregoing descriptions 
 are absolutely scientific. To lead the miner into the 
 mysteries of orthoclase, plagioclase and triclinic feld- 
 spar would be to hopelessly bewilder him ; yet many 
 of the distinctions between the various eruptive and 
 intrusive rocks are based on the one or other of these 
 feldspars being the predominant component. The use 
 of a powerful microscope is often necessary to settle 
 disputed questions, and all rock-students know how 
 many of these there are. If the descriptions will 
 enable a person to distinguish a granite from a por- 
 phyry, a felsite from a basalt, or a trachyte from a 
 quartz-porphyry, they will serve their purpose; in- 
 deed, they would almost do so if they will separate an 
 eruptive or volcanic rock from a schist, and a schist 
 from a shale. The student who once begins to take an 
 interest in rocks will soon discover that their varieties 
 are almost infinite, but that they resolve themselves 
 into a few tolerably well defined groups, and will in- 
 
ROCK-WORMING MINERALS AND HOCKS. 57 
 
 evitably be led to examine into their differences and 
 perpetually to ask himself the reason why. When the 
 eye is -thus trained it is time enough to name these 
 slighter differences, which are puzzling enough to 
 expert observers. 
 
 A general term for many of these eruptive rocks is 
 "trap," from a Scandinavian word meaning steps or 
 stairs, in allusion to the forms in which they often 
 "weather." This weathering, a term applied also to 
 the changes which take place on the surface of rocks 
 exposed to the destructive action of the elements, is 
 sometimes of great assistance in determining the 
 true character of the rock, especially in those with a 
 fine grain and dark color, as the feldspar on exposure, 
 instead of retaining the glassy look which it may have 
 in the mass (making it hard to recognize), becomes 
 milky white and shows distinctly on the surface of the 
 bowlders, even though in a clean new fracture the 
 latter may be nearly uniform dark bluish-gray or 
 almost black. In other cases the outer surface may be 
 pitted with little angular holes from which the crystals 
 have been dissolved, thus readily separating the rock 
 from the stratified series to which it may otherwise 
 have much resemblance. If depending on the pitted 
 surface, however, care must be taken to ascertain that 
 the pits are not "casts" of crystals of iron pyrite, as 
 this mineral is abundant in all rocks whether eruptive 
 or stratified, especially so in the former when decompo- 
 sition of the mica or hornblende has set in. 
 
 SECONDAKY COMPOUND BOCKS, STRATIFIED SERIES. The 
 character of the rocks which are in process of decay 
 and are being swept into the smaller streams and 
 thence through the rivers to the ocean, plays an im- 
 portant part in the formation of soils and the sedi- 
 ments carried away by water and deposited to form 
 rocks. If granite were the only rock being worn away 
 by a stream, and the disintegration were complete, we 
 should have clean deposits of sand and clay full of 
 
58 
 
 PROSPECTING AND VALUING MTNE8. 
 
 mica and hornblende. But when the stream began 
 to cut into other rocks there would ensue a change in 
 the character of the deposits, which would become 
 yet more strongly marked if the destruction of the 
 rocks had extended into groups already stratified. It 
 is, therefore, easy to see that the conditions surround- 
 ing the format! jn of stratified rocks are very complex, 
 and we must look for great local differences even in 
 rocks made at the same geologic period. So great is 
 this difference at times that it would be impossible to 
 place many rocks in their right chronological order if 
 it were not for the fossil remains with which they 
 abound, so that the prospector should religiously pre- 
 serve all such fossils as he may find, or take such a 
 note of the locality that he may direct others to it. 
 
 The ultimate analysis of the foregoing compound 
 original rocks gives approximately the percentages 
 shown in the following table, compiled from Geikie, 
 from which it will be seen that they resolve them- 
 selves into three groups chemically. The large per- 
 centage of iron and manganese in the porphyries and 
 basalt is largely due to the presence of grains of mag- 
 netic iron in the porphyries, and the oxides of iron 
 and manganese in the basalt. 
 
 CHEMICAL COMPOSITION OF ORIGINAL COMPOUND ROCKS. 
 
 
 Silica. 
 
 Alumina . 
 
 Lime. 
 
 Iron, Man- 
 ganese, etc. 
 
 Potash. 
 
 Soda. 
 
 Magnesia 
 
 Granite. 
 
 % 
 
 72 
 
 % 
 
 15 
 
 % 
 
 1 6 
 
 % 
 
 2 2 
 
 5 1 
 
 2 8 
 
 0*3 
 
 Quartzite 
 Syenite 
 
 77 
 60 
 
 13 
 
 17 
 
 0.7 
 4 4 
 
 1.1 
 7.0 
 
 4.3 
 6.6 
 
 0.7 
 2.4 
 
 1.0 
 2.6 
 
 Trachyte 
 Porphyries . . . 
 Basalt 
 
 60 
 53 
 45 
 
 17 
 16 
 15 
 
 3.5 
 6.3 
 10.5 
 
 8.0 
 14.0 
 15.0 
 
 5.0 
 1.3 
 1 5 
 
 4.0 
 2.2 
 3 5 
 
 1.0 
 6.0 
 
 6 5 
 
 
 
 
 
 
 
 
 
 The potash, soda and magnesia, being soluble, are 
 carried away on decomposition, and form the alkaline 
 matter which accumulates in lakes without outlets, 
 
ROCK-FORMING MINERALS AND ROCKS. 59 
 
 such as Walker, Mono, Pyramid, and other lakes in 
 the Great Basin between the Sierra Nevada and Rocky 
 Mountain ranges in the United States, giving them 
 their intensely saline character if the rocks furnishing 
 the material contain but little magnesia, and a bitter 
 taste if there be much of the latter present. Thus the 
 drainage of a basalt region should furnish magnesian, 
 and of a trachyte country saline waters. 
 
 The silica, alumina, lime and iron are thus left to 
 form the sedimentary rocks. The iron plays its part 
 chiefly as a component of the clays and a cementing 
 material for the sandstones, to be afterward leached 
 out and accumulated in local deposits as bog iron, 
 which by the changes of time becomes the source of 
 other iron deposits of various kinds. The lime, being 
 less soluble than the alkalies, is slowly leached out of 
 some of the rocks, especially by water containing car- 
 bonic acid, and redeposited on exposure to the air as 
 a sediment by the springs which have dissolved it, or 
 is carried to the ocean to furnish material for the 
 coralline structures or the shells of its multitudinous 
 life. 
 
 The guartz and clay, the chief constituents left, fur- 
 nish the bulk of the sedimentary material, which, with 
 the addition of waterworn fragments of undecomposed 
 rock naturally resolves the deposits into two series, to 
 the first of which belong the conglomerates, gravels 
 and sands, and to the second the muds and clays 
 (derived chiefly from the alumina), shales and slates. 
 
 All material washed into a stream by the rainfall on 
 the adjacent hills, and falling therein by the under- 
 mining action of the current on the banks, becomes a 
 source of sedimentary deposits. If the fragments are 
 too large to be moved by the current, they remain in 
 the stream bed until gradually worn away by the attri- 
 tion of smaller rocks and sand over them ; if smaller 
 and movable, they are only carried along to the first 
 dead water, whether it be a lake or the ocean, and thero 
 
60 PROSPECTING AND VALUING MINES. 
 
 deposited, and this deposition involves a sorting of 
 the material. The larger and heavier pieces will be 
 deposited first as coarse gravel, then finer gravel, then 
 sand, and the finest sediment being carried the fur- 
 thest will be laid down as mud or silt, unless the lake 
 be so small and the current of the stream so swift that 
 it is swept into the outlet beyond, leaving only a deposit 
 of sand and gravel. It will thus be seen that the same 
 material may appear as gravel at one place, sand at 
 another, and mud at another. But large streams 
 usually carry only the finer sediments when they reach 
 comparatively level country, having left the larger 
 particles at the foot of the mountain slopes, and as in 
 the case of the Amazon they may spread this over a 
 sea bottom hundreds of square miles in extent. A 
 similar process is carried on at the sea beaches where 
 the reflux of the tide may carry the finer material sea- 
 ward, leaving the coarser at the foot of the bluffs. 
 
 While stratification usually occurs horizontally, it 
 is not necessarily so, as in the case of mountain 
 streams the coarse gravel would accumulate the most 
 rapidly, forming a sloping bank, on which the layers 
 deposited in successive flood times would take the 
 same inclination. So, in like manner, the ashes 
 ejected from volcanic cones, falling on the sloping 
 sides of the same, would accumulate in layer after 
 layer, presenting all the appearance of deposits made 
 in water, but retaining the slopes of the flanks of the 
 cone. 
 
 Conglomerates are largely formed on sea beaches by 
 the rolling of the rocks washed out of the shore bluffs 
 into rounded fragments, which will naturally be of 
 various kinds of rock, according to the material of the 
 hills which are being worn away. Deposits formed by 
 river action are apt, from the circumstances under 
 which they are formed, to be much more limited in 
 extent than those made along shore lines. They con- 
 sist of rounded pieces of rock of various kinds 
 
ROCK-FORMlAls MINERALS AND ROCKS. 61 
 
 cemented together either with hardened clay or silica, 
 and sometimes with iron oxides derived from percolat- 
 ing waters or the black sand. They may be fairly 
 fine if made of gravel, or excessively coarse, and, if 
 made up chiefly of one rock, may be known by the 
 name of that if it is specially desired to distinguish 
 and separate them, as quartz-conglomerate, or 
 trachyte-conglomerate such as is found in connection 
 with the lavas of the California gold-gravel channels. 
 Some of the schists contain bowlders, leading to the 
 conclusion that they are, in this case, merely altered or 
 metamorphic conglomerates; and in other cases the 
 cementing process is so perfect and the consolidation 
 of the mass so complete that the pebbles will break in 
 two on a general line of fracture, without becoming 
 removed from the mass. Cuttings through conglom- 
 erate beds stand with nearly vertical walls. 
 
 Sandstones consist essentially of sand cemented to- 
 gether with iron, each grain being coated with a thin 
 film of iron oxide, which imparts the general color to 
 the mass, as in the red sandstones. The grains of 
 sand when cleaned of the coating may be either tinted 
 or colorless. Mica forms a common addition to many 
 sandstones, as well as lime and clay, when they may 
 be distinguished as mica-sandstone, etc. The lime 
 and clay are not readily discernible to the unaided 
 eye. Flagstones are only sandstones which split easily 
 into thin slabs, suitable for sidewalks. Buhrstones 
 are sandstones so thoroughly cemented that they are 
 very hard and rough enough to furnish the grinding 
 surface required in millstones. "Freestone" is some- 
 times a sandstone which cuts freely in any direction, 
 either with the stratification or across it, but hardens 
 on exposure to the air. The term is however some- 
 times applied to limestones and other rocks which 
 present the same characteristics. 
 
 Quartzite is a sandstone which has been subjected 
 to the action of heated waters, which have aggregated 
 
62 PROSPECTING AND VALUING MINES. 
 
 the grains of sand together with a silicious cement, 
 probably derived from a partial solution of the grains 
 of sand themselves, until the rock has lost its granular 
 structure, and to a large extent resembles massive 
 quartz. It is a common rock in mining regions, and 
 occurs with other metamorphic rocks, but also in situ- 
 ations where the associated strata have undergone no 
 change. 
 
 Clays are formed out of the alumina in the feldspar 
 and other minerals, silica excepted, of the eruptive or 
 volcanic rocks, and are the finest of the sediment car- 
 ried in suspension by water, varying in color and com- 
 position according to the rock to which they owe their 
 origin, and the particular stage in the journey of the 
 stream at which they were deposited. They may be 
 exceedingly pure, in which case they are called "fat" 
 in the language of the brickmaker and potter, and 
 from this range downward to a clay loam, in which 
 there may be a very large excess of impurities, of 
 which iron forms a large part. The richer clays 
 require the addition of sand to make good brick, but 
 possess the advantage of a more uniform composition, 
 which enables the manufacturer to regulate the addi- 
 tion of sand to a nicety and thus produce an article of 
 uniform quality; the poorer kinds make only the most 
 inferior grades. 
 
 Fireclay. A good fireclay has a composition of 
 silica 73.82%, alumina 15.88%, oxide of iron 2.95%, 
 water 6.45, with traces only of lime, sulphur, mag- 
 nesia, soda and potash, which is very nearly the 
 chemical composition of granite, with the lime, potash, 
 soda, and magnesia eliminated, so that such clays 
 could easily be formed by the decomposition of that 
 rock. Fireclay is largely associated with coal seams, 
 the clay floor retaining the waters which made the 
 tangled swamps in which many coal beds were prob- 
 ably formed. 
 
 Kaolin or porcelain clay is derived from the decom- 
 
ROCK-FORMING MINERALS AND ROCKS. 63 
 
 position of the feldspars of the granitic rocks and por- 
 phyries, and is essentially a compound of the oxides of 
 silicon and aluminum mixed with water, the composi- 
 tion when pure being silica 46.3%, alumina 39.8%, 
 water 13.9%. Impurities are frequently present, the 
 principal one being iron derived from the other min- 
 erals present in the rock from which it was formed. 
 When pure it is white, ranging through yellowish to 
 brownish red, when much iron is present, say 5% or 
 upward. The preparation of the clay by grinding, 
 washing and settling is a slow and tedious process. 
 
 Shales are only hardened clays which have been de- 
 posited from time to time in thin sheets, so that the 
 resulting mass splits readily into thin layers along the 
 lines of deposit; but while they all retain this common 
 character, they vary greatly in composition, and may 
 be distinguished from each other by the names of the 
 minerals which may give a special appearance to the 
 rock, as mica-shale, hornblende-shale, silicious shale 
 (when sandy) or simply clay-shale. In color they vary 
 as much as in composition, from pale gray to black ; in 
 the latter case they are usualb r colored by small scales 
 of graphite black-lead or plumbago derived from 
 the carbon of the organic matter washed down with 
 the clay sediment and buried with it. This organic 
 matter may be so abundant that the shales may be 
 called bituminous or oil-shales. 
 
 Slates. For all this series of rocks the term slate 
 is also very generally used, as clay-slate, mica-slate, 
 etc. ; but, strictly speaking, the term slate is applied 
 only to those rocks which have lost their shaly char- 
 acter by end pressure cm the strata, and now split on the 
 lines of cleavage, as previously defined, such as roof- 
 ing slate (pi. 12, fig. 4). In these latter rocks the 
 particles have rearranged themselves at right angles to 
 the line of pressure. This effect has been repeatedly 
 produced exprimentally, and the student must early 
 relinquish the common idea of the absolute rigidity of 
 
64 PROSPECTING AND VALUING MINES. 
 
 rocks. As a matter of fact, they are plastic or may be 
 molded to an extraordinary degree, many of the shales 
 and slates having been folded and wrinkled like sheets 
 of paper, and this not only on a grand scale, but down 
 to the most minute plications. Samples of this fold- 
 ing are shown in pi. 12, fig. 8, where the folding 
 element has been the intrusion of the dike d; and in 
 pi. 4, fig. 6, where the cause has been general lateral 
 pressure, crowding the rocks into a smaller amount of 
 space horizontally. Not only can cold lead under a suffi- 
 cient pressure be squeezed as a jet through an aperture 
 suitably provided, but cold iron can also be pressed so 
 as to penetrate into the angles of suitable molds. This 
 facility with which rocks can be modified in their 
 structure, and bent and folded, has an important in- 
 fluence on the filling of veins, as intense heat is 
 developed in the process, and this, in the presence of 
 water, will decompose and rearrange all the compo- 
 nents of the rock, dissolving some which are replaced 
 by new combinations and producing metamorphism. 
 
 SECONDARY GROUP, METAMORPHIC SERIES. All the 
 shales and slates may be thus converted into schists, 
 previously described. As in the case of the shales, 
 each variety may be distinguished by the predominat- 
 ing or characteristic mineral, as mica-schist, which 
 gradually shades off into gneiss, which is a rock hav- 
 ing a composition exactly like granite, but without 
 the uniform crystalline character of the latter, or the 
 foliated structure of the schists. In gneiss there is a 
 tendency for all the mica to be laid in horizontal or 
 more strictly speaking parallel lines, while the quartz 
 may occur in pure bands, and there is a tendency of 
 the mass when viewed on the large scale to look like a 
 coarsely stratified rock. From this characteristic ap- 
 pearance there may be a gradual change until it is 
 hard to say whether the rock should be called gneiss 
 or granite, leading us to the conclusion that many so- 
 called granites are only the last stage of the metamor- 
 
ROCK-FORMING MINERALS AND ROCKS. 65 
 
 phisrn of an original sandy bed of clay containing 
 mica, such as are common everywhere. 
 
 When hornblende is the chief mineral, we have 
 hornblende-schist, a tough, dark greenish rock, which 
 shales off into a rock so essentially composed of horn- 
 blende that it loses the schistose character and be- 
 comes what is called hornblende rock. When the 
 shading off is in the direction of a more crystalline 
 structure, the gradations may be toward a hornblende- 
 gneiss, and from that to syenite, just as the mica schists 
 grade into granites. It will, of course, be understood 
 that these changes are not to be seen in small speci- 
 mens, but only in the large area of a mountain range. 
 
 When the metamorphism has proceeded so far that 
 the micas have been decomposed, so as to liberate the 
 magnesia by the absorption of water, we have a series 
 of rocks all of which are characterized by a smooth, 
 slippery, greasy feel to the touch, commencing with 
 talcose schists, of a greenish or yellowish tint; inclin- 
 ing to reddish from the decomposition of the minerals 
 containing iron. On further change we may have 
 asbestos, forming in the seams and joints of the rock, 
 or the whole mass may be converted into soapstone, 
 which is a compact whitish or greenish rock, without 
 pronounced crystalline structure, easily cut by the 
 knife or turned in a lathe. From its infusibility and 
 the facilit3 r with winch it can be cut into suitable 
 blocks, soapstone forms an excellent lining for fur- 
 naces which are subjected to intense heat. 
 
 Chlorite-schists are similar in composition to 
 talcose schists, but the talc is replaced by an apple- 
 green mineral called chlorite, which not infrequently 
 occurs along with quartz in mineral veins, as on the 
 mother loile in California and elsewhere. 
 
 This series of rock 3 may be thus summed up, on two 
 lines of progressive alteration, according to the start- 
 ing point: 
 
 (1) Sands, sandstones, quartzite; (2) muds, clays, 
 shales, schists, gneiss, syenite or granite. 
 
66 PROSPECTING AND VALUING MINES. 
 
 SECONDARY GROUP, FRAGMENTAL SERIES. Besides the 
 rocks previousl3 T described, all of which show evidence 
 of deposition in water and something like a regular 
 order, there are still a few which cannot strictly be 
 classed with them. These are either volcanic or glacial. 
 
 Volcanic Products. Yolcanic outbursts are often 
 accompanied by the discharge of enormous quantities 
 of dry dust and stones, some of which are rounded and 
 others angular, or the dust may be an impalpable 
 powder. Some of these may have been deposited 
 under water, when they naturally have a distinct strat- 
 ification; while in those laid down in the open air 
 this structure may not be so well defined, though the 
 alternating character of the material ejected may have 
 formed apparently stratified layers on the sides of quite 
 steep mountain cones. The discharges may consist 
 entirely of lava fragments, or may include pieces of all 
 the rocks traversed by the volcanic vent, and in many 
 cases they have been cemented together by a lava 
 paste. The various conditions in which they are 
 found suggest appropriate names, as volcanic con- 
 glomerate, where the pebbles and bowlders are 
 rounded; volcanic breccia, where these are angu- 
 lar; volcanic agglomerate, where there is a mixture of 
 the two foregoing, usually without any distinct strati- 
 fication. The finer materials are called tufas or tuffs 
 and as a rule are distinctly stratified ; and while of 
 volcanic origin may contain organic remains or fos- 
 sils, equally with ordinary water-formed sediments. 
 The term lapilli is applied to the coarser portion of 
 the volcanic dust, so largely ejected prior to the ap- 
 pearance of lava at many volcanic vents, to distinguish 
 it from the finer volcanic ash, which may be a powder 
 so fine that it can be carried hundreds of miles by the 
 wind before finding a final restin * place. This finest 
 ash forms a large part of the sediment brought up from 
 the floor of the deep sea, where it gathers as slowly 
 and silently as dust in a deserted room. 
 
ROCK-FORMING MINERALS AND ROCKS. 67 
 
 Glacial Products. While all the material dis- 
 charged by glaciers into running streams is undistin- 
 guishable from other sedimentary deposits, those 
 dropped by melting ice present only faint traces of 
 sedimentation or none at all. Where floating ice is 
 dropping its load of earth, sand, gravel, rounded 
 bowlders and angular fragments, on the top of strata 
 which are forming under the surface of lakes or shal- 
 low seas, we may find immense bowlders or bunches of 
 gravel irregularly mixed with such deposits, which, 
 while they betray the condition of the climate at the 
 period of their formation, do not justify any special 
 name to such accumulations of sediment. But where 
 the glacial deposits are laid down by ice in deep 
 waters, where the deposit of river or ocean sediment 
 is forming very slowly, we shall have an irregular ac- 
 cumulation of material, without the regular stratifica- 
 tion of river deposits, showing only what may result 
 from the more rapid descent of the largest pieces, 
 which, if they fell on a surface already smoothed by 
 the more slowly descending finer sediment, would pre- 
 sent faint traces of sedimentation, but the lines would 
 not be traceable for more than comparatively short 
 distances, the successive deposits fading out laterally 
 and overlapping each other. Such also are the de- 
 posits of bowlder clay which have also been formed by 
 the grinding action of an ice sheet. There is nothing 
 to prevent such deposits carrying ore, except the irreg- 
 ularity in their composition on account of the wide area 
 from which they may be drawn, and the uncertain 
 distribution of the valuable metals in the earlier rocks. 
 
 GEOLOGIC SUCCESSION OF EVENTS. *It is scarcely with- 
 in the scope of the present volume to enter into a 
 description of the geological succession of the rocks, 
 as it would require a volume by itself and be of little 
 practical value to the miner, except as regards coal 
 and iron, the character of which is largely influenced 
 by their geologic age, owing to the changes which 
 
68 PROSPECTING AND VALUING MINES. 
 
 have taken place in their composition with the lapse 
 of time under the influence of heat and pressure. 
 
 The accompanying table gives the outline scheme 
 adopted by the U. 8. Geological Survey. The pro- 
 gression is from the bottom upward, the order being 
 as shown in the stratified rocks now accessible, though 
 the whole series does not appear in any single locality. 
 Below the Archaean is the granite foundation. "Era" 
 and "period" relate to time; "system'' and "group/ 9 
 to the rocks. Subdivisions of periods and groups are 
 called "epochs" and "formations" (according to time 
 and rocks respectively). The names for these smaller 
 divisions vary in different localities, and authors differ 
 in classifying and naming them, so that a more com- 
 plete presentation here would only be confusing. 
 
 ORDER OF SUCCESSION OF GEOLOGIC TIME AND ROCK FORMA- 
 TION. 
 
 Era or System, Period or Group. 
 
 Era of Man ............................ Quaternary. 
 
 I Pliocene. 
 Cenozoic or Tertiary .................. < Miocene. 
 
 ( Eocene. 
 
 ( Cretaceous. 
 Mesozoic .............................. -< Jurassic. 
 
 ( Triassic. 
 
 f Permian. 
 
 I Carboniferous. 
 Palaeozoic .............................. -{ Devonian. 
 
 I Silurian. 
 
 [ Cambrian. 
 
 [See also the arrangement proposed by LeConte and Dana, pp. 332, 323.] 
 
CHAPTER IV. 
 PHYSICAL CHARACTER OF MINERAL DEPOSITS. 
 
 MINERAL deposits may be roughly classed under 
 three heads : Beds, veins and masses. These divis- 
 ions correspond to differences in form, and, in part, 
 to differences in origin. 
 
 BEDS. A large proportion of the rocks met with 
 consists of substances arranged in distinct stratified 
 layers. If any of these layers consists of a useful 
 mineral, or contains enough to make it valuable, it is 
 said to be a deposit in the form of a "bed," "seam," or 
 "stratum," sometimes spoken of as a "bedded vein" 
 or "blanket vein. " The most important of all bedded 
 or stratified deposits is coal; but in addition there are 
 beds of iron ore, copper-bearing shales or slates, lead- 
 bearing sandstones, silver-bearing sandstones, gold, 
 tin and platinum-bearing gravels, as well as beds of 
 rock salt, clays, slates, limestones, gypsum, oil shales, 
 etc. The characteristic feature of a bed is that it is a 
 member of a series of stratified rocks, and as such was 
 laid down or formed after the rocks on which it rests, 
 and before those which lie on its top. This peculiarity 
 at once distinguishes a bed from a true vein. 
 
 Eoof and Floor. The layer above it is called the 
 "roof "of the deposit and the onebeiowit the "floor," 
 when it remains horizontal or nearly so, but when 
 highly inclined the terms "hanging wall" and "foot- 
 wall," applied to true veins, are equally applicable 
 to beds, but less expressive. 
 
 Thickness. This is the distance from the roof to 
 
70 PROSPECTING AND VALUING MINES. 
 
 the floor at right angles to the inclination of the floor, 
 being the shortest distance between the roof and floor, 
 and this may be very much less than the length of a 
 crosscut run through the deposit on a horizontal line, 
 the two becoming nearer in length as the bed ap- 
 proaches more and more to the vertical ; in the latter 
 case they would be equal. 
 
 Dip is the inclination of the floor from a hori- 
 zontal plane, and may be spoken of either in degrees 
 of a circle, as for example ten degrees (10); or ex- 
 pressed in feet, as 1 in 10, 1 in 20, etc. Other equiva- 
 lent terms are "slope," "pitch" "underlie" and 
 "inclination." Dip, of course, is due to the disturb- 
 ance of the deposit by elevation or depression, causing 
 tilting or bending, since its formation (a horizontal 
 layer having no dip); but as such disturbance has 
 been almost universal, nearly all bedded deposits have 
 more or less dip, at the present day. Sometimes the 
 beds may be nearly horizontal, as in Staffordshire, 
 England ; or raised to an angle of 50 as in the Cumber- 
 land coal series in the Skagit Valley, Wash. (pi. 2, fig. 
 10); sometimes they may be vertical or even folded 
 over as in pi. 4, fig. 6, a structure which is found in 
 the Appalachian mountains, and in some of the Franco- 
 Belgian coal fields, where a vertical shaft passes six 
 times through the same bed, because the folding has 
 been so complicated. 
 
 Strike. The strike or course of the bed is the di- 
 rection of a horizontal line drawn along the floor of 
 the deposit, such as the bottom of a tunnel following 
 the mineral, without grade. This direction will 
 clearly be at right angles to the dip of the bed, and 
 will consequently vary as the dip varies; so that, if it 
 is desirable to run a tunnel on a deposit in a perfectly 
 straight line, it must have a course or direction as 
 nearly as possible at right angles to the general dip, 
 instead of to the dip at any particular locality. But 
 this is not always possible. 
 
PHYSICAL CHARACTER OF DEPOSITS. 71 
 
 From the above it will be clearly seen, by reference 
 to pi. 13, figs. 10, 11, 12, 13, that while in fig. 10 the 
 strike would be east, in fig. 11 it would vary from 
 northeast to east and thence to southeast; in fig. 12 
 it would be north, going round by east until it was 
 south; while in fig. 13 it would turn to all points of 
 the compass in succession and indicate a saucer-shaped 
 basin. From what has been previously said it will be 
 obvious that even when the bed may be covered on 
 the surface its position, if it exists beyond the point 
 of discovery, should be traceable by the rocks with 
 which it is associated ; but a search in this manner 
 should be governed by the rock which forms the roof, 
 as this must lie comformably above it, while it is pos- 
 sible that the deposit may lie on the upturned edges 
 of a great variety of rocks as at E, pi. 2, fig. 1. 
 
 The thickness of workable beds varies within very 
 wide limits according to their richness in some special 
 mineral or its scarcity. Some workable beds of coal 
 are only 1 ft. thick and range up to as much as 60 ft. 
 or over in exceptional cases. The copper-bearing 
 shales of Mansfeld are only from 10 to 20 in. thick, 
 while the lead-bearing sandstones at Mechernich are 
 no less than 85 ft., and some beds of slate, limestone 
 and salt greatly exceed these dimensions. But what- 
 ever the thickness may be at any particular point, it 
 does not follow that this will be maintained over the 
 entire area of the deposit. Sometimes this may be the 
 case over a very extensive area, but there must neces- 
 sarily be a boundary to the deposit in all directions, 
 and toward these limits it may dwindle away to a 
 feather edge, with the probability of the greatest 
 thickness being near the central portions of the orig- 
 inal deposit (not necessarily that part left to our inspec- 
 tion). Toward these edges, as in the case of coal and 
 iron deposits, the bed may contain many impurities 
 and become valueless; or in the case of slates and 
 limestones a gradual change may take place into 
 
72 PROSPECTING AND VALUING MINES. 
 
 another kind of rock, such as clay-shales into sand- 
 stones and these into conglomerates. PL 2, fig. 1, D, 
 shows a bed of coal, as originally laid down, thinning 
 out in all directions. It may consist of a uniform 
 mass, with impure edgings, or it may be divided into 
 several layers by thin sheets of clay or waste matter, 
 called "partings," in which case it often happens that 
 the character of the coal above a parting is different 
 from that below in important particulars, and should 
 be mined separately. Partings are not necessarily a 
 detriment to a deposit, as they frequently facilitate 
 mining. 
 
 Outcrop. It is not always easj' at first sight to dis- 
 tinguish the outcrop of a bed from that of a true vein, 
 but it will usually be found more continuous and more 
 uniform in its composition. 
 
 VEINS may be described as comparatively thin sheets 
 traversing what are called " country rocks," which 
 were formed earlier than the veins themselves; and 
 occupy crevices formed by fracture of the inclosing 
 rocks, or have been formed along the lines of junction 
 of such rocks by changes in those adjacent,, It is this 
 origin at a later date than that of the rock formation 
 which constitutes the essential difference between a 
 vein and a bed. 
 
 Dikes. The above description includes all veins of 
 porphyry or other intruded rocks, such as granite or 
 basalt, as well as those containing the useful or pre- 
 cious minerals. Veins filled with porphyry or similar 
 rocks of whatever kind are usually called "dikes." 
 
 True Veins. The term "vein" is more properly 
 restricted to those which are more or less filled 
 with useful minerals, whether in workable quan- 
 tities or otherwise. Building stone should be excluded 
 from this definition, as many valuable varieties (besides 
 those found in beds) are the product of dikes. In 
 the United States the terms "vein," "lode," "lead" 
 or "ledge" are used indiscriminately in different 
 
PHYSICAL CHARACTER OF DEPOSITS. 73 
 
 localities, but all have the same meaning, while in 
 Australia and South Africa the term "reef" is often 
 applied to mineral veins as well as to bedded deposits 
 like gold-bearing conglomerates. For the purposes of 
 the U. S. land offices the description of a lode as given 
 by Justice Field in the celebrated case of the Eureka 
 Cons. vs. the Richmond Co. is accepted, viz.: "We 
 are of opinion, therefore, that the term [lode], as used 
 iu the acts of Congress, is applicable to any zone or 
 belt of mineralized rock,lying within boundaries clearly 
 separating it from the neighboring rocks." This 
 definition evidently covers both true veins and all 
 bedded deposits. 
 
 Miners often speak of coal and iron veins, but this is 
 a misapplication of the term. When a bed lies on the 
 upturned edges of much older rocks, as in pi. 2, fig. 1, 
 E, it shows conclusively that before its deposition long 
 periods of time had elapsed, in which the lower strata 
 had been raised above the water, uplifted into new 
 positions, worn down to a new surface and again de- 
 pressed below the water level; and we can form some 
 comparative idea of the relative ages of bedded veins 
 by the thickness of the strata which have accumulated 
 above them. In the case of true veins we can only 
 judge of their age by knowing that they must be 
 younger than the rocks in which they lie, and the 
 comparative age of these is judged by the fossil 
 remains found in them. 
 
 Dip. Like beds, veins have dip, strike and walls. 
 As a usual thing the dip of true veins is apt to be 
 steeper than that of the majority of beds, though such 
 a distinction is not absolutely necessary. The dip is 
 measured from a horizontal line as in the case of beds, 
 and is expresed in degrees. If the vein is vertical the 
 dip is 90. In pi. 9, fig. 1, the veins A, B, C, and D, 
 have respectively dips of 47, 68 and 86, while vein 
 E is vertical (90). In some cases the dip may be so 
 flat that when the vein is exposed by the wearing away 
 
74 PROSPECTING AND VALUING MINES. 
 
 of the hanging wall it may appear almost like a bed. 
 Such cases are often termed "blanket-veins," but a 
 very slight examination will show, in most cases, their 
 true origin. 
 
 Strike. Owing to their different origin, the strike 
 of true veins is more likely to have a uniform direction 
 than in beds, as the inclosing rocks have not usually 
 been subjected to so much movement since the forma- 
 tion of the fissure as has been suffered by the strata 
 containing the beds; or, if movement has taken place, 
 the weakness of the fissure has directed the motion 
 into that plane and simply caused a reopening of the 
 fissure, and not infrequently a refilling of it with a 
 different class of mineral deposits. See pi. 6, fig. 6, 
 where the thin slabs of rich gold ore B occur on each 
 side of a large central core of poor or barren quartz A. 
 The conclusion is frequently irresistible, taking into 
 consideration the great amount of motion of the walls 
 of the lode as shown by their shattered condition, that 
 on a reopening of the fissure the contents of the lode 
 were concentrated in the way shown, to the im- 
 poverishment of the main body of quartz. 
 
 Outcrop of Veins. The outcrop of a vein, sometimes 
 called "croppings," is the portion of the vein exposed 
 on the surface. It does not follow that the visible out- 
 crop corresponds with the true strike of the lode. 
 This can only occur when the vein is vertical, or out- 
 crops in a level plain, when it would show a compara- 
 tively straight line and the true course, whatever the 
 dip mi^ht be. It is not often that such a case occurs, 
 On the contrary we find the bulk of mineral veins in 
 rough and broken mountain regions, and in these cases 
 the tracing of the outcrop becomes a more difficult 
 matter, especially when the vein crosses ravines or val- 
 leys filled up with gravel or debris which hide its 
 presence. All veins with a pronounced dip have a 
 crooked or serpentine outcrop, and the fiatter the dip 
 the more sinuous this outcrop will appear. By refer- 
 
PHYSICAL CHARACTER OF DEPOSITS. 75 
 
 ence to pi. 9, figs. 1, 3 and 5, these peculiarities will 
 be easily understood. Their great importance be- 
 comes apparent when making locations on a vein and 
 in the legal aspect of these locations. Fig. 1 is a 
 longitudinal section along the bed of a ravine, show- 
 ing five veins A, B, C, D, E, and their outcrops ascend- 
 ing the hill on the side furthest from the observer, as 
 from g to s, h to r, k to p, I to o, and m to n. All the 
 veins are supposed to run north and south. It is evi- 
 dent that on the crest of the ridge the outcrop of the 
 vein A, dipping east, will be west of its position in 
 the gulch by the distance sa, while in the cases of the 
 veins B, C, D, dipping west, the outcrops on the ridge 
 will be east of the position of the veins in the bed of 
 the gulch as shown at A, k and I by the distances br, 
 cp, and do. It can also easily be seen that on de- 
 scending the opposite side of the hill, the outcrop of 
 A would swing back again up the ravine, while all the 
 others would swing down, producing, if the outcrops 
 were continuous, an appearance something like that 
 in figs. 3 and 5. In fig. 3 we have details of the out- 
 crop of two veins, B, B, and C, C, running north and 
 south on the two sides of a ridge, and both dipping to 
 the west; and in fig. 5 similar details of two veins A, A t 
 and Z>, D, dipping east. The outcrops in fig. 3 are 
 shown by the black lines A, A, and D, Z), and in fig. 5 by 
 the similar lines B, B, and G, C. A little study of these 
 figures will make the matter clear, without elaborate de- 
 scription. All the peculiarities of the outcrop may be 
 illustrated by taking a large smooth potato, and cutting 
 it into halves lengthwise. Lay the two halves flat side 
 down on the table side by side and we have two minia- 
 ture hills with a ravine between them. Now if a cut be 
 made across both hills inclining from right to left we 
 shall have a vein in miniature, and if the pieces be 
 drawn slightly apart so as to show the white of the 
 inside in contrast with the brown skin, the pale line 
 thus made visible will indicate the outcrop of the 
 
76 PROSPECTING AND VALUING MINES. 
 
 vein, and will be found similar to figs. 3 arid 5. By 
 making the first cut flat and subsequent ones steeper 
 the gradual approach of the outcrop to a straight line 
 as the view becomes more and more vertical will be 
 quickly apparent, until the vertical cut will represent 
 the vein E in pi. 9, fig. 1. 
 
 The outcrop may either be a very conspicuous 
 object standing many feet above the surrounding sur- 
 face or barely visible on the hillside; it may be merely 
 outlined by a surface depression, or form a deep gorge, 
 according to the relative hardness of the vein matter 
 and the country rock, or the difference in the contents 
 of the vein at different points in its length. 
 
 Dikes, which have a nearly uniform composition 
 throughout their length, often traverse a country for 
 miles, standing up like ruined walls, as at the Devil's 
 Slide in Utah, on the Union Pacific railway, and at 
 other places which nearly every traveler can recall, 
 but such uniformity very seldom exists in mineral 
 veins. On the mother lode of California the barren 
 portions are largely made up of threads and stringers, 
 while the valuable portions consist of immense bodies 
 of solid quartz, which have protected the present hills 
 from wear and tear, while the ravines have been cut 
 out alongside the lode (pi. 7, fig. 6) or through the 
 barren portions at right angles, or nearlj* so, to the 
 vein, as in pi. 9, fig. 7, where A, A, represent quartz 
 bodies; B, the barren intermediate ground and c,c, 
 the visible outcrops. This structure is continuous for 
 many miles. In Mariposa county especially the heavy 
 white quartz crops out from the crests of one hill 
 after another, crossing their summits like the comb of 
 a helmet, in a most conspicuous manner, with deep 
 intermediate ravines. In these cases the ravines are 
 due to the absence of ore in the outcrop, but in other 
 cases the ravines are due to the presence of soft, friable, 
 easily decomposed ore in the lodes, and form along the 
 veins, in gorges of varying depth according to the 
 
PHYSICAL CHARACTER OF DEPOSITS. 77 
 
 degree of difference in hardness between the lode and 
 its wall rocks. A good illustration of this structure is 
 found in the Monte Cristo district on the west slope 
 of the Cascade range in Washington, where the abrupt 
 bluffs, forming the walls of an ancient glacier basin, 
 are furrowed with deep, abrupt gorges, similar to pi. 
 9, fig. 6. The veins here cut across the slates with a 
 dip of about 60, and having undergone extensive 
 alteration, besides being mineralized with friable ores, 
 are now softer than the metamorphic slates, so that as 
 the vein wore away the overhanging wedge of rock B, 
 broke off from time to time, leaving a steep slope to 
 the footwall side of the ravine, and a nearly vertical 
 bluff above the hanging wall, from which large frag- 
 ments are annually detached by the action of frost and 
 sunshine, widening the ravine, while at the same time 
 the melting snows deepen its bed along the course of 
 the vein. In such cases the foot of the bluffs is cov- 
 ered with an immense " talus" or broken rock slope, 
 consisting of angular frost-detached fragments broken 
 from the cliff above, which have buried the outcrops 
 in the lower portions of the valley, roughly indicating 
 their position, however, by winrows of immense bowl- 
 ders which have been detached, for want of support, 
 from the overhanging wedge B } and have rolled down 
 the slope without being more than partially broken 
 up in the fall. 
 
 In other cases the hardness of the vein matter and 
 that of the inclosing rock may be so nicely balanced 
 that they both wear down at about the same rate, and 
 the croppings may be covered with earth, etc., or as 
 the prospector says, "blind;" that is, hidden or hardly 
 visible; or the vein may become blind because since 
 the time of its formation new strata or volcanic over- 
 flows have been laid down upon the containing rocks, 
 as in pi. 15, figs. 13 and 14, which show such a case 
 in longitudinal and cross section. In this case if 
 ravines have cut down through the "cap-rock" the 
 
78 PROSPECTING AND VALUING MINES. 
 
 vein may be seen cropping on the side of the ravine as 
 at A, fig. 13, being lost under the cap B, but reap- 
 pearing at C on the other side of the hill. 
 
 This cap may be either sedimentary or eruptive 
 rock, or it may be the consolidated snow (nere) of a 
 snowfield, both forms being seen in the Monte Cristo 
 region; so that the importance of determining accu- 
 rately the strike and dip of the vein, so as to recognize 
 it on both sides of the mountain, becomes very appar- 
 ent. 
 
 But in whatever manner the outcrops may occur the 
 same rule will generally hold good for quite an exten- 
 sive district or group of veins, and a recognition of 
 this fact may save the prospector many a weary mile 
 of travel and hard climbing. 
 
 If the vein has a very flat dip and is located on a 
 more or less conical hill, it may even crop entirely 
 round the summit of such a peak, as shown in pi. 7, 
 figs. 10, 11, in which fig. 10 is a vertical section and 
 fig. 11 a ground plan of the same. We have here a 
 series of trap dikes with bedded quartz veins lying 
 between granite and slate. The drawings represent 
 the Yanderbilt mine near Silver Peak, Nevada, and 
 show a similar structure to that of the Tyndall mine 
 in Colorado. 
 
 Spurs. It not infrequently happens that a vein pre- 
 sents more than one outcrop, the main lode presenting 
 itself at the surface with several minor lateral 
 branches, as shown in the cross section of the Dol- 
 coath mine, pi. 7, fig. 1. These are generally more 
 numerous on the hanging wall side of the lode, and 
 present in the greatest numbers when the dip of the 
 vein is flat, as was the case in the Comstock lode, of 
 which a general idea is presented in pi. 2, fig. 2. 
 These ' 'spurs" may run nearly parallel to the main 
 lode, and standing more vertically unite with it in 
 depth, or they may run out into the general bedding 
 of the rock, as shown in pi. 6, fig. 2, s y s,s. In the 
 
PHYSICAL CHARACTER OF DEPOSITS. 79 
 
 former case it is easy to understand how the cracks in 
 which they are formed were made by the weight of 
 the overhanging wedge breaking it across from time to 
 time, or the sliding of the hanging wall on the foot- 
 wall pulling it apart, a cause which might also give 
 rise to the spurs which branch out into the bedding. 
 
 Horses. In other cases, especially in very large 
 veins, these spurs after leaving the vein may reunite 
 with it in all directions, resulting in a mass of barren 
 rock entirely surrounded by vein matter, to which the 
 term "horse" is usually applied. These are fre- 
 quently spoken of as masses of rock which have fallen 
 into the fissure, but they have usually moved but a 
 very slight distance, if at all, from their original posi- 
 tion. 
 
 Walls. When the vein is vertical the walls may be 
 distinguished by the points of the compass, as the 
 north, south, east or west wall, but when the vein has 
 a slanting dip the lower wail is designated as the 
 "foot wall" and the upper as the "hanging wall," as 
 in pi. 7, fig. 7, where the granite forms the foot wall, 
 and the slates the hanging wall of the quartz series B. 
 In England the term "cheeks" is sometimes applied to 
 the walls. 
 
 Gouge. Not infrequently there occurs between the 
 vein matter and the country rock a seam of clayey 
 matter called "gouge" or "selvage," which may be of 
 extreme thinness or reach a thickness of as much as 30 
 ft., as in the Potosi mine on the Cromstock lode. 
 This is apparently the result of a grinding or crushing 
 movement of the walls of the vein upon each other, 
 under enormous pressure, and where a portion of the 
 vein has been mixed with material from the walls the 
 gouge is often rich enough in mineral to go to the 
 reduction works. Mine clay may also result from 
 chemical decomposition of the wall rocks. 
 
 SlicJcensides. Where the motion has been consider- 
 able, and the walls or vein are hard enough to resist 
 
80 PROSPECTING AND VALUING MINES. 
 
 the grinding action and reduction to clay, both the 
 wall and the vein matter become marked with parallel 
 lines or strice, called "slickensides, " or "slickens," 
 which indicate the direction of the motion, and fre- 
 quently the quartz or wall has taken a polish equal to 
 anything which can be produced artificially. 
 
 "Frozen" Veins. In other cases it may happen 
 that there is only one well defined wall, the vein mat- 
 ter being firmly attached to the other, and gradually 
 fading out into the barren country rock, as shown in 
 pi. 6, fig. 3, where (7, 6 y , may be slates or any other 
 rock; A, a dike cutting the same, and B the ore vein 
 with a well defined wall on the right hand but 
 "frozen" to the dike on the left side. The condition 
 of the walls is a matter of much interest to the miner. 
 If the ore is frozen to its alls on both sides it is 
 almost a positive indication of uncertainty of continu- 
 ance in depth, but heavy clay seams or gouges are 
 taken as favorable indications from the evidence they 
 supply of a deep-seated fissure. 
 
 Vein Matter. The material with which the vein is 
 filled is known as the "gangue" or "matrix," usually 
 by the former term. It is not necessarily quartz. It 
 may be limespar (calcite, calcspar) fluorspar, barytes, 
 or even the decomposed remains of a porphj^ry dike. 
 The term matrix alludes to the filling being the 
 mother of the ore. It does not follow that all this 
 gangue carries ore, or that it is of uniform thickness 
 through the entire length of the lode. The movement 
 of the walls may have brought two swells opposite 
 each other, as in pi. 6, fig. 2, at B and in pi. 2, fig. 9, 
 and the vein is then said to "pinch" or "peter out;" 
 or the ore maj 7 be confined to slabs on the walls, as in 
 pi. 6, fig. 6, where B may represent ore and A the 
 barren quartz gangue. Eig. 5, on the same plate, is 
 an exaggerated representation of a condition fre- 
 quently seen in the softer kinds of granite, where 
 instead of the vein pinching completely, as in fig. 2, 
 
PHYSICAL CHARACTER OF DEPOSITS. 81 
 
 the motion since the vein was filled with quartz (black) 
 has been able to reduce the portions of the wall rock 
 between the swells B, B, to a condition of gouge or 
 nearly so, and a new wall has been established as 
 W y W. 
 
 Ore Chutes. It may happen that all the gangue or 
 matrix is charged with ore, but this is seldom the 
 case. In the majority of cases there are wide and long 
 barren spaces in the lode and the ore is concentrated 
 into "chutes" (also spelled "shoots"), as shown in 
 pi. 9, tig. 7, A, A. These may vary greatly in dimen- 
 sions, being sometimes so short horizontally in pro- 
 portion to their length that they are called "pipes." 
 In addition to the dip, which they have in common 
 with the vein, they have an inclination to the right or 
 loft of a line drawn on the dip at right angles to the 
 strike, which his called the "rake." For instance, 
 looking down an incline on the vein, the ore may go 
 off to the right or left of this incline, and this feature 
 is usually common to all the veins in a district which 
 have the same strike and dip, and the rake is usually 
 the greatest in the flattest veins. In pi. 9, fig. 2 (a 
 cross section) shows the dip of the vein, and fig. 4 (a 
 longitudinal section) the rako of the ore chute C, 
 which is estimated from the true dip line, in this case 
 37. 
 
 MASSES. Under this head are included irregular 
 deposits which cannot be classed as either beds or 
 veins. Their forms are various, and sometimes they 
 are mereb' indefinite impregnations in permeable 
 ground, leached out from finely disseminated mineral 
 in the surrounding country rocks. Some iron and 
 manganese ore bodies, formed in troughs or cup- 
 shaped depressions, are best described as "masses," as 
 also are many segregated deposits of tin, copper, and 
 silver ores. The most pronounced type is perhaps to 
 be found in the large isolated bodies of lead and zinc 
 ores in limestone. Small deposits, of whatever min- 
 
82 R08PECTING AND VALUING MINES. 
 
 eral, are called "pockets" or "bunches." The main 
 characteristics of masses are irregularity and isolation ; 
 but these do not prevent their being, in many instances, 
 very valuable. If their shape is decided in any direc- 
 tion, they may be said to have strike, dip, rake or 
 pitch, roof and floor, or walls, etc. 
 
CHAPTER Vo 
 ORIGIN OF VEINS. 
 
 ALL veins of whatever kind, whether bearing valua- 
 ble minerals or not, are the result of movements in the 
 upper portions of the earth's crust, producing cracks 
 or crevices, which have been subsequently enlarged 
 and filled with some material different in its physical 
 and chemical qualities and appearance from the rocks 
 in which the fracture has taken place. 
 
 These movements, which may be the result of earth- 
 quakes, or the readjustment of the pressure caused by 
 the thinning of one portion of the crust by denuda- 
 tion and the thickening of another portion by the 
 deposition upon it of all the material brought down 
 from the mountains by the action of rivers, are inti- 
 mately connected with the process of mountain build- 
 ing, and consequently show themselves most striking!}* 
 in mountain regions, in which also volcanic agencies 
 have played a most important part. 
 
 FISSURES AND FAULTS. Such fractures in the rocks, 
 when they have been accompanied with more or less 
 motion of one side of the mass upon the other, or of 
 both on each other, are known as "faults'* or disloca- 
 tions. They may show themselves only by a mass of 
 broken material, or the break may be comparatively 
 clean- cut, and may be very short, or extend for many 
 miles, as in New Zealand, where one earthquake (1845) 
 produced a fissure in the southern island which aver- 
 aged 18 in. in width and was traceable for a distance 
 
84 PROSPECTING AND VALUING MINES. 
 
 of 60 miles parallel to the axes of the mountain chain, 
 while the earthquake of 1855 gave rise to a fracture 
 which could be traced along the base of a line of cliffs 
 for a distance of about 90 miles. 
 
 But whatever the cause and however long the fissure 
 may be, it must terminate at each end somewhere, 
 otherwise it would cut the world in two; and it is evi- 
 dent that however great the elevation or depression of 
 the bounding walls at any one point, there can be no 
 such motion at its two extremities; and that the 
 grinding action of the motion, which prepares the fis- 
 sure for the formation of a mineral vein, must be 
 nothing at either end, and greatest where the displace- 
 ment of the walls has been most extensive. 
 
 It does not, however, follow that all fissures will 
 produce mineral veins, for there must be a combina- 
 tion of circumstances to cause such depositions; but 
 as these faults may have been, and often have been, 
 formed subsequent to the formation of bedded de- 
 posits such as those of coal, iron or gold-bearing 
 gravels, it is therefore necessary to know something 
 of the features which these faults present to enable us 
 to again find a broken bed or vein when lost in the 
 course of working. 
 
 Throw. The simplest form of fissure is shown on 
 pi. 3, fig. 4, AB, with the greatest motion at n,o; CD 
 in the same figure (after Geikie) shows a fissure split- 
 ting at the ends into minor branches, the amount of 
 "throw" or displacement of the walls being given in 
 figures, which indicate the greatest movement in the 
 middle, as before explained ; while EF shows one in 
 which the walls have been drawn apart at right angles, 
 or nearly so, to the main fissure, forming "spurs." A 
 similar structure is shown in pi. 6, fig. 2. In(7Z>, pi. 
 3, fig. 4, while the greatest total movement has been 
 say 30 ft. it does not follow that all this movement was 
 on one side of the fissure, for one side may have been 
 raised and the other depressed in varying proportions. 
 
ORIGIN OF VEINS. 85 
 
 These figures are horizontal plans. PL 1, figs. 3, 4, 5 
 6, 7, show the simplest kind of fault in vertical cross 
 section, if the break were an absolutely straight line, 
 which, however, is not often, if ever, the case. Fig. 
 3 shows a fracture in a series of bedded rocks without 
 any apparent displacement, although it is possible that 
 there might have been such horizontally. Figs. 4 and 
 5 show a movement of either or both of the two walls 
 on each other in the direction of the arrowheads; but 
 there would be nothing in such a case, as the fracture 
 is clean cut, to indicate the dij'ection in which the 
 movement had taken place, whether the foot wall had 
 been depressed as in fig. 5 or elevated as in fig. 4, or 
 the reverse in the case of the hanging walls; but in 
 fig. 6, 7, the movement is clearly shown by the bent 
 and broken edges of the strata, to be an ordinary fault 
 or depression of the hanging wall in fig. 6. 
 
 Reverse Throw. Elevation of the hanging wall (or 
 depression of the foot wall) is shown in pi. 1, fig. 7. 
 Such a throw is also seen in pi. 11, fig. 5, from the 
 gravel pit at Laporte, Cal. The direction of the 
 throw is called the "hade. " 
 
 Pockets Formed by Faulting. If a fault, instead 
 of being a clean, straight cut, has a sinuous or wavy 
 form, as in pi. 2, fig. 7, the result of motion of the 
 walls in the direction of the arrowheads would be very 
 different, producing the form shown in fig. 8, or a 
 vein of very uniform width throughout, if the move- 
 ment were a mere separation horizontally; whereas, if 
 the movement had been in the direction of the arrows 
 in fig. 9, the swells of one wall may have been brought 
 against the swells of the other wall, resulting in a 
 series of lens-shaped pockets, especially if the course 
 or strike of the lode be also sinuous and it has suffered 
 more or less longitudinal as well as vertical displace- 
 ment. On sinking on the outcrop at a, fig. 9, the vein 
 would be found widening rapidly, forming what the 
 Mexicans call an "A" vein; while, if the surface had 
 
86 PROSPECTING AND VALUING MINES. 
 
 been worn away to the dotted line be, similar sinking 
 would reveal a vein rapidly diminishing in width or a 
 "V" vein. 
 
 Very rapid widening of an ore body in this way is 
 liable to be accompanied by an equally rapid contrac- 
 tion, and vice versa. An easy method of getting a 
 thorough understanding of this important phase of 
 fissure structure is to tear a piece of paper in two 
 halves along a wavy line such as is shown on pi. 2, fig. 
 7; when, by moving them apart in various directions 
 upon a dark background, every phase of the question 
 can be readily studied, particularly if in one instance 
 the waves are made short and deep, and in another 
 long and gentle. PL 6, fig. 5, is an exaggerated illus- 
 tration of such structure, to show that when the ore 
 (black) is lost at B the search for the next swell must 
 be continued by following the crosshead or seam which 
 cuts the ore body off (this being the original fissure 
 line), and not by following the false wall W W, which 
 has only been formed by the motion and pressure 
 crushing the swells of the country rock AB into a shat- 
 tered mass of vein matter; or, yet worse, by presum- 
 ing that the course of the ore body is the general 
 course of the vein, and following that direction into 
 the country rock on one of the joints which originally 
 determined the shape and position of the swells on the 
 line of fracture. 
 
 Gashes. When such fissures have been formed by 
 pressure from below bulging the surface upward as in 
 pi. 2, fig. 4, a simple gash may have been formed, 
 which was later on filled with mineral matter from 
 above or laterally; or by the action of surface waters, 
 became, as we so often find, the line of a watercourse 
 following an anticline e. A sagging in a syncline 
 might conceivably give rise to the opposite effect, as 
 in fig. 5. 
 
 Step Faults. In other cases, the elevation has been 
 so great, and the strain on the strata so enormous that 
 
ORIGIN OF VEINS. 87 
 
 when they did give way the central mass with the 
 largest base exposed to the elevating force has been 
 thrust furthest upward, while the masses on either 
 side have settled down in gradually lessening steps 
 until the movement fades out into undisturbed coun- 
 try, producing a series of "step faults/' of which pi. 
 
 1, fig. 1 is an ideal and fig. 2 an actual illustration, 
 the latter being taken from the reports of Prof. Em- 
 mons on Leadville, Col., where the drop of 2,000 ft. 
 at the Mosquito fault is reduced going westward to 
 only 750 ft. at the Carbonate. 
 
 Trough Faults. The faults shown in pi. 3, figs. 1, 
 
 2, 3, known as " trough faults/' are more compli- 
 cated, and are best explained in the language of Mr. 
 Jukes, who proposed the following satisfactory solu- 
 tion of the problem: "Suppose the beds AA, BB, 
 etc., fig. 2, to have been formerly in a state of tension, 
 arising from the bulging tendency of an internal force, 
 and one fissure, FE, to have been formed below, which 
 on its course to the surface splits into two, ED and 
 EC. If the elevatory force were then continued, the 
 wedge-like piece of rock between these two fissures, 
 being unsupported, as the rocks on each side sepa- 
 rated, would settle down into the gap as in fig. 3. If 
 the elevatory force were greater near the fissure than 
 further from it, the single fissure below would have a 
 tendency to gape upward, and swallow down the 
 wedge, so that eventually this might settle down, and 
 become fixed at a point much below its previous rela- 
 tive position. Considerable friction and destruction 
 of the rocks, so as to cut off the corners g, h, fig. 3, on 
 either side, would probably take place along the sides 
 of the fissures, and thus widen the gap, and allow the 
 wedge-shaped piece to settle down still further. 
 When the forces of elevation were withdrawn, the 
 rocks would doubtless have a tendency to settle down 
 again, but these newly included wedge-shaped and 
 other masses would no longer fit into the old spaces, 
 
88 PROSPECTING AND VALUING MINES. 
 
 so that great compression and great lateral pressure 
 might then take place/' PI. 4, fig. 5, (after Jukes) 
 shows such a fault or wedge cutting into a bed 
 of coal, which from the enormous pressure resulting 
 from the resettlement of the strata "has been reduced 
 to a paste of coal dust and very small coal." 
 
 Very frequently the line of fault becomes the bed of 
 a watercourse and in time a ravine. This may result 
 not only from the weaker nature of the rock on this 
 line (as evidenced by the faulting itself), but also 
 from the tilting of strata along the fault plane. Such 
 a fault-formed valley may or may not at present be 
 occupied by a watercourse. PL 12, fig. 9, shows a 
 canon following a fault in Death Valley, Cal. 
 
 Every mountain region is full of faults, and they 
 abound especially along the great ranges, where the 
 movements have been so great as to bring to the sur- 
 face, alongside of each other, rocks which in the order 
 of succession are separated by many thousands of feet; 
 and in these movements we have an explanation of the 
 sudden change in the character of mineral deposits on 
 opposite sides of lofty mountain chains which some- 
 times seem inexplicable. But almost every vertical 
 exposure of rock in such places as railroad cuttings, 
 and not only of rock but of unsolidified beds of sand 
 or gravel and clay, shows a multitude of minor fis- 
 sures intersecting and displacing each other, some- 
 times in the most complicated manner, but presenting 
 evidence of the universality of the process which has 
 opened the way for the circulation of underground 
 waters, without which it would seem that the filling of 
 a portion of the fissures could not have been accom- 
 plished. 
 
 There does not appear to have been any time in the 
 earth's history since the first solidifying of the surface 
 when such fracturing and movements have not been 
 going on, and consequently we find veins of one age 
 intersected and sometimes dislocated by others formed 
 
ORIGIN OF VEINS. 89 
 
 on fractures of later date, until in some cases there 
 may result a very complicated condition, as shown in 
 pi. 2, fig. 6, which a thorough knowledge of the 
 theories of faulting alone can explain, and for want of 
 which loss and disappointment may ensue from min- 
 ing operations therein. It does not, however, follow 
 that because one vein may be apparently faulted and 
 thrown by another, such is always the case, as at the 
 crossing of AA and (7(7, where the fissure A may 
 have jumped along because the line of least resist- 
 ance may have been different on the two sides of (7, 
 which would make A younger than O\ but where the 
 dragging of the rocks is present, as at the intersection 
 of AA with BB, the presumption is strong in the 
 absence of other evidence that AA has been faulted 
 and thrown by BB. 
 
 Clockworks. The complication arising from these 
 sources may be so intricate that it becomes impossible 
 to say which set of fissures is of most ancient date, 
 and they may become so numerous and minute that 
 individual mining becomes an impossibility, and the 
 mass is extracted as a whole, if extracted at all, under 
 the name of a "stock work. " 
 
 Rocks vary so greatly in their hardness, texture, 
 composition, brittleuess, and facility of splitting that 
 they break in very different ways, and this peculiarity 
 must inevitably exert an influence on the character of 
 the fissures by which they may be traversed, and a 
 knowledge of what may be expected in. each case is 
 essential to a clear understanding of the methods to 
 be employed in opening and working mineral veins to 
 the best advantage. 
 
 " True Fissure Veins." Anyone of the faults shown 
 in pi. 1, which must evidently extend downward to an 
 unknown depth, may under certain conditions form 
 what is known as a "true fissure vein" (an old-time 
 term for what was thought to be the best and most 
 permanent type of a mineral deposit), which is simply 
 
00 PROSPECTING AND VALUING MINES. 
 
 a fissure, sometimes miles in length, coursing directly 
 across the country in a more or less straight line, and 
 cutting through the rocks indiscriminately, but vary- 
 ing in width and character according to the rock in 
 which it may occur both in length and depth, and 
 tilled with mineral matter other than eruptive rocks. 
 
 Strike Faults. A fault may cut the rock formations 
 at right angles to their strike, or it may run more or 
 less parallel with the strike, but cut the rocks on their 
 dip, by being usually more nearly vertical than the 
 strata penetrated, in which case the vein would be 
 formed on a "strike fault/' and at the surface present 
 many resemblances to what is known as a "contact 
 vein." 
 
 Effect of Country Bocks on Fissures. If the fissure 
 is entirely in the same rock it may maintain a toler- 
 ably uniform character for its entire length and depth, 
 but if it cut rocks of various kinds it may pinch out 
 almost entirely in those which are tough, expanding 
 in those which fracture more easily, either from split- 
 ting readily (as slates) or from extra brittleness (as 
 certain quartzites). If it traverse a limestone forma- 
 tion it may for a time completely Jose the character of 
 a fissure vein with definite walls, in a comparatively 
 short time after its formation, on account of the great 
 facility with which lime is removed by the action of 
 water, especially when containing carbonic acid, and 
 the irregular cavernous structure thus caused. 
 
 It therefore becomes an important question when 
 ore is found in a certain rock to ascertain to what 
 extent that rock is developed, and whether the associ- 
 ated rocks are of such a character for hardness or soft- 
 ness that a vein, as the miners say, can live in it* 
 The writer has in mind an extensive region where the 
 disregard of these general principles has led to the 
 useless expenditure of large sums on veins which a 
 very slight geological knowledge would have taught 
 the miners could not be of permanent value, because, 
 
ORIGIN OF VEINS. 91 
 
 however rich the surface ores, they were contained in 
 the fragments of a bed of schists overlying a tough 
 solid syenite, in which the vein exposures were very 
 narrow, and into which the veins found in the schists 
 would inevitably pass in their lower portions. 
 
 If the vein has been formed on a strike fault, there 
 is a yet greater chance of irregularity from the ten- 
 dency of the break at times to follow the bedding 
 planes of the rocks, while at others it cuts through 
 them, resulting in shattered masses which form 
 "horses" or barren patches of country rock in the 
 middle of the ore body ; or the fracturing may have 
 been so extensive laterally that we have a mass of 
 parallel threads and stringers, instead of a smaller but 
 more compact deposit. 
 
 CONTACT VEINS. From such veins as the latter the 
 passage is easy to those formed on the contact of two 
 bodies of rock of different kinds. Such contacts may 
 be divided into four groups: (1) Contacts between 
 sedimentary rocks such as slate and quartzite, quart- 
 zite and limestone, or sandstone and conglomerate; 
 (2) contacts between sedimentary and intrusive or 
 igneous rocks, such as slate and granite, or limestone 
 and porphyry; (3) contacts between two igneous 
 rocks as porphyry and syenite; and (4) contacts on 
 the walls of dikes which may traverse a series of either 
 sedimentary or igneous rocks. 
 
 When contact veins of the first two classes stand at 
 a high angle or approach the vertical there is at first 
 sight but little difference in their appearance from 
 fissure veins, but as they alwa3 7 s maintain the same 
 relation to the inclosing rocks they are apt to have a 
 more uniform character both in structure and filling. 
 It is plain also that they must partake of all the wavy 
 irregularities of shape which have been imparted to 
 the rocks in their upheaval, and if followed downward 
 to a sufficient depth must eventually flatten out, as no 
 beds of stratified rock can continue to descend toward 
 
92 PROSPECTING AND VALUING MINES. 
 
 the center of the earth indefinitely, from the very 
 nature of their origin; still, the contact is usually of 
 great extent, and there is no reason why the vein 
 should not be so also. 
 
 This feature becomes especially pronounced when 
 the contact lies nearly horizontal or only slightly 
 inclined, as at Leadville, because we are able to reach 
 it with comparatively shallow shafts over large areas, 
 the extent of w 7 hich in one direction represents the 
 strike of a vertical lode, while the extent in the other 
 is practically the same as the depth reached on the 
 vertical lode only by deep sinking with all its limita- 
 tions. In such horizontal contact deposits we do not 
 look for horizontal motion, and have only to encounter 
 the troubles arising from subsequent faulting, as in pi. 
 1, figs. 1 and 2, but in many cases of steeper contacts 
 there are evidences of vertical motion, in which case 
 we shall usually find the contact to be local and acci- 
 dental ; the fissure being really a strike fault con- 
 tinued to the surface on a contact plane which proved 
 to be the line of greatest weakness, as in the case of 
 the Comstock lode in Nevada, which strikes nearly 
 parallel with the axis of the mountains on whose flanks 
 it is located, and presents varying contacts in Virginia 
 City, Gold Hill, and Silver City, but has been proved 
 to descend into the syenite at Virginia City, below 
 the level of the Sutro tunnel, the character of the lode 
 changing at the same time as well as the composition 
 of the ore. Thus evidence of motion in an apparently 
 contact vein may be taken as prima facie proof that 
 the contact is not continuous, and that the vein really 
 belongs to the group of fissure veins, and will partake 
 of all their peculiarities of structure and filling. 
 
 When two sedimentary rocks are conformable, but 
 have a more or less wavy surface of junction, a sliding 
 movement of one upon the other will give rise to open- 
 ings and pinches, just as in the case of secondary 
 faults on warped planes in homogeneous rock, and an 
 
ORIGIN OF VEINS. 93 
 
 opportunity for the formation of a contact vein is 
 presented, as in pi. 1, fig. 8. Such a vein might be 
 regarded as either a contact deposit or a fissure vein, 
 but is more naturally considered in the former class. 
 
 As the rocks on the two sides of a contact are seldom 
 of equal hardness the character of the vein will prob- 
 abb r be governed by that which is most liable to 
 decay, removal or fracturing. This is especially the 
 case with slates and limestones, the former on account 
 of the facility with which they split and crush; the 
 latter because they are so easily dissolved. 
 
 Compression Veins. No person with any experi- 
 ence in the mountains can have failed to notice the 
 folds and bends in slate rocks, from gentle waves to 
 minute crumplings, which have been produced by 
 forces pressing on the ends of the lines of stratifica- 
 tion, until a structure similar to that shown in pi. 6, 
 fig. 1, has been reached, a structure which can be 
 easily imitated by squeezing the leaves of a book to- 
 gether endwise, between the covers, held slightly 
 apart. If such slates are on a line of contact, as at 
 the Keystone mine, Amador County, Cal., and have 
 been subjected to such pressure, many good mines 
 have been the result; but where such action has taken 
 place in the body of a large mass of slate, in the 
 absence of an3 r special controlling element, such as a 
 dike, great uncertainty will exist as to the extent of 
 the movement, which, having full play in all direc- 
 tions, may have simply resulted in a multitude of 
 irregular minor foldings. In all such cases the whole 
 vein does not consist of a continuous sheet of ore, 
 although there may be such at the immediate contact, 
 but of a series of lenticular masses, overlapping each 
 other, which may occupy a belt several hundred feet 
 in width, the broadest portion of one being generally 
 opposite the thin end of another. It is obvious that 
 such mines will require extensive cross-cutting to 
 make certain that no ore body has been overlooked. 
 
94 PROSPECTING AND VALUING MINES. 
 
 Limestone Contacts. In a limestone contact, 
 whether steep or flat, the actual line of contact which 
 will form one wall of the lode may be comparatively 
 smooth, while that in the limestone may be very 
 irregular, depending somewhat on the solidity of the 
 limestones or their varying degrees of solubility, and 
 the destruction of the limestone by this means may be 
 so complete that the ore body will apparently consist 
 of a cemented conglomerate, the pebbles in which are 
 only the insoluble cherty or flinty residue so abundant 
 in chalk and silicious limestones. 
 
 The remaining groups may be considered together, 
 as while there may be cases of contact of two eruptive 
 rocks without the presence of a dike, as on the Corn- 
 stock, the majority of contact veins in purely eruptive 
 rocks are alongside of or controlled by dikes cutting 
 masses of some other variety, as in many Colorado 
 mines. The essential feature of all lodes formed on 
 the contact of dikes is that the latter have been 
 squeezed from below into the fissures as they were 
 formed, and that consequently their walls must extend 
 downward to the source of the pasty rock with which 
 they were filled, and that this source is, in depth, 
 beyond our ability to explore. While such contact 
 lodes thus present a general similarity to fissure veins 
 in their length and depth, they possess one important 
 feature not present in the latter that one wall of the 
 fissure is always of the same composition, a fact which 
 will tend to maintain a more uniform character in the 
 filling, at least on one side of the vein. The wall away 
 from the dike will, of course, be liable to changes as 
 the rock of which it is formed varies, but such changes 
 will be rather those incident to the influence of the 
 heat of the injected dike, as the baking of clay shales 
 into jaspery or flinty products, rather than variations 
 in the shattering of the walls, as the forcing apart of 
 the walls of the fissure and simultaneous filling with a 
 plastic substance would prevent grinding of the faces 
 
ORIGIN OF VEINS. 95 
 
 of the fissure against each other, while such fragments 
 of the walls as did fall off would be buried in the 
 intruded mass, and carried by it upward on its course 
 toward the surface if the rent extended that far. In 
 such lodes we may find a sudden change in the prin- 
 cipal mineral on passage from one rock to another, but 
 ^ constant admixture of some other ingredient which 
 owes its presence to that of the adjacent dike; 
 Dr the ore on one wall may be of a totally different 
 character from that on the other, as at the Key- 
 stone mine, where, next to the so-called green- 
 stone hanging wall, the quartz is massive, white and 
 blocky, while that of the slate foot wall is banded with 
 numerous parallel blackish lines of slate, making the 
 "ribbon rock" of the miners; or, as on the Comstock, 
 where the nearly vertical ore bodies in the porphyry, 
 as they approach the much flatter syenite foot wall, 
 carry an appreciably larger proportion of gold ; or, as 
 at a mine in northern Washington, the ore on one wall 
 may be distinctly a silver proposition, and on the 
 other, only 15 ft. away, as decidedly a gold one. 
 
 In all these cases of dike contacts, the point at 
 which ore will form and the shape of the deposits will 
 be governed by the same influences as in other con- 
 tacts, whether the lode has been formed by the gradual 
 shrinkage of the mass of the dike in cooling, or by 
 substitution through the circulation of water along its 
 bounding planes. 
 
 Gash Veins. Shrinkage of sheets of lava may also 
 produce veins which will not extend into the underly- 
 ing granite or other rock, as at the Stonewall Jackson 
 mine, Ariz. Such occurrences may be classed with 
 the "gash veins." 
 
 Segregated Veins. In other cases, like that shown 
 in pi. 7, fig. 5, there may be neither a clean cut fissure 
 nor a line of contact, nor a controlling dike, but a 
 series of ore bodies arranged along a general line of 
 shattering and without definite walls, the change in 
 
96 PROSPECTING AND VALUING MINES. 
 
 the rock becoming gradually less marked laterally until 
 it fades out into the unaltered country rock. Such 
 occurrences are known as "segregated veins, " by 
 which term it is understood that the mineral has been 
 concentrated by the action of water into the crevices 
 of a shattered or sheeted belt of rocks from the sur- 
 rounding rocks themselves. This "sheeting" is well 
 seen in many mines in granite, where an apparently 
 solid and smooth wall will scale off in slabs or sheets, 
 after a short exposure to the air, making it almost im- 
 possible to say where the true wall may be, and ren- 
 dering a large opening necessary to secure a relatively 
 small amount of ore. Many miners make the mistake 
 of considering all the sheeted mass as a part of the 
 vein, thus deceiving themselves with the hope that the 
 ore body may ultimately be as wide as the sheeted por- 
 tion. A little study will show the falsity of such a 
 notion, as it is quite conceivable that the step faults 
 shown in pi. 1, fig. 1, might be so numerous that the 
 spaces between would not exceed the thickness of the 
 slabs just spoken of. Most faults through rocks which 
 do not break too easily into small fragments show this 
 sheeted structure, as the result of the dragging of the 
 sides at the moment of fracture. Where there has 
 been much of this action we may look for more or less 
 numerous veins parallel to the main lode of a district, 
 which maj' carry more or less ore, but being only inci- 
 dents accompanying the principal disruption are less 
 likely to afford the conditions which will develop them 
 into lodes of equal value. 
 
 GENERAL CONCLUSIONS. It may therefore be set down 
 as an axiom in mining that as a prior condition to the 
 formation of mineral veins there must have been such 
 fracturing of the rocks as to facilitate the circulation 
 of underground waters vertically as well as horizon- 
 tally, and that the nature of the fissures thus produced 
 will be influenced by the varying hardness, brittleness 
 or solubility of the rocks thus fractured, as well as by 
 
ORIGIN OF VEINS. 97 
 
 the direction in which the force may have been applied. 
 The "filling" of the vein will depend on other condi- 
 tions, but one may reasonably expect that the structure 
 of veins in granite, for instance, will be similar in 
 widely separated mining camps; and so of veins in 
 tou:h limestone, or easily fissile slates, and other 
 characteristic rocks; and we may take the generaliza- 
 tion still further, and expect to find all the veins in 
 any mining district, in the same rock and belonging 
 to the same system, similar to each other in filling as 
 well as structure. 
 
 But it does not follow of necessity that all veins in 
 any particular region are of the same age. On the 
 contrary we frequently find several systems, each char- 
 acterized by a general common strike and dip, show- 
 ing that such regions have been the seat of several fis- 
 sure-forming disturbances, which may have been of 
 very widely varying force, and followed by fillings of 
 a totally different character; but usually the most 
 strongly developed system will either show a decided 
 parallelism to the general direction of the mountain 
 range, or else nearly at right angles thereto; and, while 
 one system may be a good ore producer, another may be 
 practically valueless. It thus early becomes necessary 
 to identify their peculiarities and avoid loss. 
 
 While absolute dislocation of the strata or rocks 
 may have been necessary to produce the entire series 
 of fissure veins, whether parallel to the strike of the 
 rocks or more or less at right angles to it, simple fold- 
 ing of the strata may have been sufficient to so far dis- 
 place the lines of contact of two sedimentary rocks as 
 to open the way for the formation of contact veins; or 
 to so far rupture a belt of rocks without actual dis- 
 placement as to permit the formation of segregated 
 veins or deposits, or to rupture horizontal beds of 
 limestone sufficiently to allow the percolation of water 
 through them, with the consequent excavation of 
 irregular chambers. 
 
98 PROSPECTING AND VALUING M1NEH. 
 
 These changes are common to all mountain regions, 
 and are not unknown even in comparatively level 
 countries, but they have not resulted in the formation 
 of mineral veins in all localities. There are extensive 
 mountains areas almost entirely destitute of valuable 
 mineral deposits; and therefore, while the preliminary 
 fracturing of a country is absolutely essential to the 
 formation of mineral veins, their subsequent filling 
 with valuable contents must be explained by the 
 operation of agencies which were local in their action, 
 and at the most very indirectly connected with the 
 agencies which formed the original fissures. The frac- 
 turing of the rocks simply made the formation of the 
 veins possible. The formation of a crevice did not 
 necessarily involve the formation of a vein, but only 
 governed the physical aspect of such a vein when 
 formed. 
 
CHAPTER VI. 
 
 FILLING OF MINERAL VEINS. 
 
 Igneous Theory not Tenable. It is a popular idea 
 that all mineral veins have been filled from below by 
 the material being forced into them while in a molten 
 condition. This would involve intense heat. While 
 there can be no question that the porphyritic and 
 basaltic dikes have been filled in this manner, a multi- 
 tude of facts compel us to look for some other explana- 
 tion for the majority of metalliferous veins. 
 
 That the intrusion of dikes has been accompanied 
 with heat is abundantly proved by the changes which 
 have been effected in the rocks through which they 
 pass, or into and between which they have been 
 squeezed as sheets. When cutting through coal beds 
 or penetrating them, as in pi. 5, fig. 6 (after Jukes), 
 which covers a length of nearly 1,000 ft., the coal has 
 been deprived of its volatile matter and becomes what 
 is called " blind coal/' or is even reduced to a small 
 quantity of black soot. Sandstones become fused into 
 a glassy quartzite ; slates are hardened into a flinty sub- 
 stance with change of color, while other rocks have 
 become porphyritic, as alongside the great trachytic 
 dike which cuts across Onion Valley in Plumas Coun- 
 ty, Cal. This dike has a width of about 30 ft. and 
 stands up as a wall on the hillside to a height of 90 
 ft. in places, and is apparently connected with surface 
 sheets which overflowed from it. The country rock is a 
 blackish green slate, but close to the dike it has been 
 so altered as to look like a porphyry, being spotted 
 
100 PROSPECTING AND VALUING MINES. 
 
 with white feldspar crystals, which gradually become 
 less conspicuous as the vicinity of the dike is left, until 
 they fade out entirely in the plain-colored, unaltered 
 general country rock. The same lava flow contains 
 large fragments of the country rock which have been 
 torn from the sides of the fissure during its formation, 
 and altered in exactly the same way, just as we con- 
 vert clay into brick by the action of heat. From these 
 well established facts we would be justified in looking 
 for similar changes in the walls of mineral veins, if 
 they have been produced in the same way. We do 
 find changes in the walls, it is true, produced by the 
 action of heat, but they are such as result from the 
 action of hot water and steam, and not of molten mat- 
 ter. The latter when once injected will gradually 
 cool off, and when once cold will produce no further 
 change, while the hot water may continue to circulate 
 for ages, so long as the source of heat remains un- 
 changed, and produce changes much more extensive 
 and more widely disseminated than the action of 
 injected lavas. 
 
 A few illustrations may render the discussion of this 
 question more intelligible, and lead naturally to the 
 important influence which rocks have on the nature of 
 the vein material. 
 
 It is well known that if we melt copper and silver 
 together we produce an alloy in which the silver is indis- 
 tinguishable except by assay or analysis, yet in the 
 Lake Superior copper mines we find blotches of white 
 silver in the heart of solid masses of native copper or 
 crystallized on the surface of the copper, showing that 
 in the latter case plainly, and in the former by infer- 
 ence, copper and silver were deposited in the vein 
 alternately, some of the silver at least after the forma- 
 tion of the copper had ceased. 
 
 At the Head Center mine, Tombstone, Ariz., crystals 
 of gold are found planted on the surface of horn silver 
 (chloride of silver) ; yet when melted together gold 
 
FILLING OF MINERAL VEINS. ' 101 
 
 and silver form an alloy with the kreatest facility, and 
 the affinity of the metals for each other is so great that 
 native gold always contains more or less silver. 
 
 At the Alston Moor lead mines in England, where 
 galena in a matrix or gangue of fluorspar is worked, 
 lead crystals (galena) are bedded in fluorspar, with lime 
 crystals (calcite) planted on the lead crystals, and 
 crystals of "blackjack" (zincblende) on the lime 
 crystals four minerals superimposed on each other, 
 one at least of them (zincblende) volatile at a low 
 temperature and another (lime) practically infusible. 
 
 In the Sierra Nevada mine, Virginia City, Nev. , a 
 seam of broken rock and clay, which has been made 
 since the formation of the vein, is filled with minute 
 crystals of red oxide of copper, formed by the coppery 
 waters which filter through it from the higher levels. 
 
 In the upper part of the wash of Furnace creek, on 
 the eastern side of Death Valley, Cal., is a beautifully 
 regular vein of fibrous limestone (satin spar) cutting 
 nearly vertically through beds of coarse conglomerate, 
 which show no signs of alteration (pi. 7, fig. 8). Fig. 
 9, same plate, shows quartz veins in the same neigh- 
 borhood and similarly located. 
 
 In the mines at Batopilas, Mexico, native silver 
 occurs in veins of calcspar, which have an extraordi- 
 nary persistence, frequently dwindling down to a mere 
 seam, often less than 1 in. wide for long distances, and 
 then opening out to a width of several feet. In places 
 probably 90% of the ore is crystallized native silver, a 
 large proportion of the remainder being crystallized 
 ruby silver (arsenical) and crystallized black sulphide 
 of silver, the latter often in branching flakes like moss 
 formed in the joints of the rock alongside the veins. 
 
 Near Yankee Hill, Butfce County, Cal., beautiful 
 specimens of crystallized gold are found in the joints 
 of the porphyries, usually in thin flakes, taking the 
 shape of combs, fern fronds, etc. In this case there is 
 no indication of veins or vein matter. 
 
102 PROSPECTING AND VALUING MINES. 
 
 At West Point, CalaveSras Co'unty, Gal., gold occurs 
 in the solid granite. At Drytown, Araador County, 
 Cal., gold occurs in limestone; and in Mariposa 
 County, near Coulterville, both in the black clay slates 
 and serpentines. At Fiddletown, in Eldorado County, 
 gold is found in the iron pyrites which abound in the 
 slates. The crystals are often of considerable size, 
 chiefly cubes, and the gold can be seen projecting 
 from the smooth faces of the crystals. 
 
 It would be possible to extend the list of similar 
 cases of crystallization indefinitely, but it is not neces- 
 sary to more than call attention to the fact that in 
 many cases, if not in all, these crystals are formed in 
 cavities, many of them of such size as to be called 
 caves or caverns, which are not characteristic of any 
 of the dikes which we know to be the result of injec- 
 tion from below. Good illustrations of this formation 
 of crystals in closed cavities may be seen in the hollow 
 balls filled with quartz crystals, called "geodes. " The 
 miners call the smaller cavities found in veins "vugs. " 
 
 Metals also occur in gash veins which must have 
 been filled from the surrounding rocks, having no con- 
 nection with the interior of the earth. 
 
 Galena occurs in irregular deposits in limestone, 
 where there is no evidence of vein structure. 
 
 Chrome iron occurs in isolated masses in blackish- 
 green hornblende schists; while platinum, iridinm, 
 osmium, etc., occur chiefly as grains in sand or gravel 
 deposits, which have probably been derived from the 
 decay of rock strata, and not from veins, as their 
 occurrence in veins is unknown. 
 
 In the case of the "compression veins" in slates, as 
 at Amador and Sutter Creek, Cal., pi. 6, fig. 1, the ore 
 bodies, carrying gold, are often completely sur- 
 rounded with slates identically the same as the black 
 clay slates to the westward of the vein, which show 110 
 trace of alteration by heat either as applied by molten 
 lava or hot water, although they have been subjected 
 
FILLING OF MINERAL VEINS. 103 
 
 to immense pressure and have been folded in every 
 direction. 
 
 In Cornwall the remarkable case occurs of a vein 
 producing copper for many hundred feet in depth, 
 while encased in slates (called "killas"), but chang- 
 ing to tin when it passes into the underlying granite, 
 as shown in pi. 8 and pi. 7, fig. 1, which represent a 
 longitudinal section and a cross section of the Dol- 
 coath mine. 
 
 Again, we have those peculiar veins in which the 
 minerals are arranged in bands parallel to the walls, 
 as in pi. 7, fig. 4. This case is similar to those in 
 which crystals of different minerals have been 
 deposited on the top of each other in succession. 
 
 In pi. 7, fig. 5., we have a case in which a band of 
 rock has been altered, and contains more or less 
 parallel ore bodies (shown in black), with numerous 
 threads and stringers connecting them, the whole 
 "stockwork" fading out into the inclosing rock with- 
 out any positive definition or walls. 
 
 Many other cases of interest might be cited, but these 
 are sufficient to show the difficulties which surround the 
 theory of igneous filling of mineral veins from below 
 by injection in the form of molten or pasty matter. 
 
 In the case of the limestone deposits there is no con- 
 nection by well defined fissures wich the interior of 
 the earth, through which the filling could have taken 
 place; and in the case of the Batopilas mines it is in- 
 conceivable that a mineral so infusible as limespar 
 could have been injected into fissures, frequently less 
 than an inch in width; while if we admit the possi- 
 bility of the lime being fused, the heat would have 
 been so intense that the adjacent rocks would have 
 been fused into lava, and the minerals found in the 
 injected material would have been volatilized and 
 entirely eliminated, unless retained by condensation 
 in the cooler surface rooks, in which case the ores 
 would be found only near the surface and in the coun- 
 
104 PROSPECTING AND VALUING MINES. 
 
 try rock as well as in the lode, and the latter would be 
 barren or unproductive in depth, which from actual 
 exploration we know is not the case. That heat does 
 operate in this way we know from the quicksilver 
 mines of Lake County, Cal., where the surface rocks 
 are filled with minute globules of mercury, which have 
 been brought up from below by the action of hot 
 springs and steam, and condensed near the surface, 
 where the temperature fell below the volatilizing point 
 of the mercury. 
 
 Similar difficulties meet us in the case of the lime 
 vein on Furnace Creek, and indeed in all cases where 
 minerals occur intimately associated with limestone, 
 either in the body of the rock itself, or in the crevices, 
 or where it becomes the gangue accompanying the ore. 
 
 The occurrence of gold in porphyry, slate, lime, 
 granite and serpentine, outside of veins, is also inex- 
 plicable on the theory of upward injection ; as also the 
 presence of minerals in gash veins and the slates Of 
 the mother lode in California. 
 
 The same appears patent of all those cases where 
 minerals are found which readily form alloys and have 
 a similar melting point, in close contact, yet each re- 
 taining its individual character; as well as in all cases 
 of superimposed crystals lining cavities or vugs in the 
 vein, especially where the cavities are of such dimen- 
 sions as to become worthy of the name of caves. 
 
 That crystals do form in dikes or veins of igneous 
 (or rather of plutonic) origin is not denied; but they 
 form a compact mass, the various minerals crowding 
 each other to distortion, and mixed in tolerably uni- 
 form proportions, as in granite and the porphyries, in 
 which cavities are almost unknown; while such 
 crystals as they do yield outside of the mass are found 
 in crevices formed at a later date than the origin of 
 the rock. 
 
 We have still the case of the Cornish veins, which is 
 only a type of many others, where the imagination can 
 
FILL I NO OF MINERAL VEINS. 105 
 
 hardly realize how a vein can be filled from below, 
 during the same operation, with copper in its upper 
 portion and tin in its lower, and why the change in 
 the character of the injected material should have 
 taken place just at the junction of the two rocks which 
 were traversed by the fissure. 
 
 In such cases as the occurrence of flakes of horn 
 silver in the joints of quartzites at the Isabel mine, 
 near Globe, Ariz., which can be scraped off, leaving 
 thequartzite absolutely barren of silver; and the same 
 ore in the joints of limestone west of Tucson, Ariz., 
 where the surface of the joints gives good assays, 
 while the silver penetrates the blocks of limestone in 
 steadily diminishing quantities for only a few inches, 
 leaving their interior entirely innocent of ore, we can- 
 not invoke the igneous theory, because there are no 
 veins to be injected. 
 
 The same may be said of the horn silver found in 
 the Leeds mine, near the southeast corner of Nevada, 
 which in many respects is one of the most remarkable 
 occurrences of silver on record. There is no true 
 vein; the matrix or gangue in this case is a nearly 
 horizontal bed of sandstone, in which are found large 
 quantities of vegetable remains, such as wood, twigs 
 and leaves, and it is these which carry chloride of 
 silver in quantity sufficient to make working of the 
 mass not only possible but profitable. In this case 
 there cannot be a suspicion of injection. 
 
 More doubt hangs over the silver ores in the 
 trachytes or rhyolites of the Calico district, San Ber- 
 nardino County, Cal., which occur in the crevices of a 
 truly eruptive rock; but even here the ores may lie in 
 fissures formed subsequently to the eruption of the 
 trachyte. 
 
 We are thus compelled to look for some other 
 method by which the fissures, now called veins, have 
 been filled with their mineral constituents. Among 
 those familiar with the subject the igneous theory, 
 
106 PROSPECTING AND VALUING MINES. 
 
 which held sway for many years, has been generally 
 abandoned as incapable of explaining the greater por- 
 tion of the phenomena. 
 
 Aqueous Theory. The distribution of ore in veins 
 is of the most irregular character. In some of the 
 gold veins of California the metal is collected in well- 
 defined pockets, containing all the way from a few 
 pounds up to half a million dollars, surrounded by 
 barren white quartz in immense quantities. In other 
 mines we find the ore in threads and stringers, more or 
 less parallel to the general direction of the walls, fad- 
 ing out into the country rock which evidently forms 
 the general mass of the vein, in fact constituting" its 
 gangue. These and other allied facts suggest the 
 modern explanation, which attributes the filling of 
 veins to the circulation of heated waters in the earth's 
 crust. 
 
 Distribution of Metals, etc., in Nature. Of late years 
 researches into the constitution of sea and min- 
 eral waters has revealed the presence in them of a long 
 list of elements in the form of salts, establishing the 
 fact of their solubility in nature as well as in the 
 chemist's laboratory. In mineral waters the metals iron, 
 arsenic, lithium, csesium, rubidium, copper, zinc and 
 manganese have been detected, along with the elements 
 of earthy minerals which form the gangue of veins, 
 such as silica, magnesia, lime, alumina, fluorine and 
 baryta; besides soda, patash, boron, chlorine, iodine, 
 bromine, phosphorus and sulphur, many of which 
 latter form salts which are excessively soluble. 
 
 Sea water, according to Prof , Forchhammer, in addi- 
 tion to the chlorides and sulphates of sodium, mag- 
 nesium, potassium and calcium, contains silica, boric 
 acid, bromine, iodine, fluorine as acid, and the oxides 
 of nickel, cobalt, manganese, aluminum, zinc, silver, 
 lead, copper, barium and strontium; and arsenic, 
 gold, lithium, rubidium, and csesium have been dis- 
 covered since Forchhammer wrote. The experiments 
 
FlLLltfQ OF MINERAL VEINS. 107 
 
 of Prof. Liversidge on the sea water off the coast of 
 Australia give positive results as to the presence of 
 gold. Other investigators also have detected gold in 
 sea water. 
 
 Daintree reports the occurrence of gold in the ser- 
 pentines and pyritic diorites of Queensland, and the 
 pyritic granites of New South Wales. 
 
 The nodules or concretions of manganese dredged 
 from the ocean floor by the Challenger expedition 
 showed the presence of nickel and cobalt. 
 
 Prof. F. Sandberger has announced the discovery of 
 small quantities of silver, lead, copper, nickel, cobalt, 
 bismuth, arsenic, antimony and tin, in silicates such 
 as olivine, augite, horneblende and mica, which are 
 constituents of igneous rocks. 
 
 Prof. Dana records the occurrence of nickel in the 
 Vesuvian lavas, and also the chlorides of lead, copper, 
 iron and manganese, as forming on the lavas at the 
 craters from the heated vapors; and similar results 
 would probably be obtained at other volcanoes had 
 they been as carefully studied. He also notes the 
 presence in minerals which form a portion of gneiss 
 and granite, of manganese, lithium, cerium, lantha- 
 num, didymium, yttrium, zinc, berylinm, titanium, 
 molybdenum and cobalt; the latter metal also in 
 mica schists with arsenic. 
 
 J. S. Curtis determined the presence of gold and 
 silver in the silicates of the rocks adjacent to the Corn- 
 stock lode, the silver chiefly in those of the hanging 
 wall diabase or porphyry and the gold in those of the 
 foot wall syenite; and when writing on the quicksilver 
 deposits of the Pacific coast of the United States, 
 Prof. G. F. Becker reports the presence of antimony, 
 arsenic, lead and copper in the underlying granites 
 at Steamboat Springs, Nev. ; and records the fact that 
 these springs are to-day depositing quicksilver, gold, 
 antimony, arsenic, lead and copper. 
 
 Daubree gives the following list of elements, ar- 
 
108 PROSPECTING AND VALUING MINES. 
 
 ranged somewhat in the degree of their importance 
 (Maskelyne adds lithium and antimony): iron, mag- 
 nesium, silicon, oxygen, nickel, cobalt, chromium, 
 manganese, titanium, copper, aluminum, potassium, 
 sodium, calcium, arsenic, phosphorus, nitrogen, sul- 
 phur, chlorine, carbon and hydrogen, several of the 
 compounds of which are peculiar to meteorites. The 
 majority of the meteoroids with which the earth 
 comes in contact are exceedingly small, and a weight 
 of 1,000 Ib. is probably uncommon, but when the 
 daily number encountered by the earth, estimated at 
 20,000,000, is multiplied by years and centuries it is 
 evident that the addition of their contained minerals 
 to the earth's surface is worthy of notice. These 
 minerals, forming part of the sedimentary strata, could 
 find their way into veins without even the intervention 
 of volcanic agency. It is more than probable that the 
 cobalt-nickel-manganese nodules of the deep sea are 
 derived from the meteoric dust falling on its surface. 
 
 Outside of the eruptive rocks we find ore minerals 
 disseminated* in secondary or stratified rocks, such as 
 slates and sandstones, as well as in limestones, and it 
 is from all of these sources combined that the metals 
 have been concentrated into veins. 
 
 Underground Circulation. It is evident that water 
 is the active factor in all these changes. We must 
 remember that a considerable portion of the water 
 which falls upon the surface of the earth does not pass 
 off promptly into the rivers, but is absorbed by the 
 earth and rocks, and by the action of gravity pene- 
 trates to depths practically unknown. Of this we 
 have absolute demonstration from its presence in the 
 quartz crystals of deep-origined eruptive rocks, as 
 numerous but exceedingly small bubbles, only visible 
 under a powerful microscope; and from the enormous 
 volumes of steam which are given off by volcanoes in 
 eruption, and which continue to be evolved from the 
 lavas after their ejection. We must not imagine the 
 
FILLING OF MINERAL VEINS. 109 
 
 crust of the earth as a solid mass, through only the 
 crevices of which water may find a passage; there is 
 abundant evidence that every particle of the earth's 
 crust to depths of which we have any knowledge, and 
 presumably far below, is charged with water, and that 
 there is no substance known which is not permeable 
 by it. Under pressure it can be forced through iron, 
 appearing as a perspiration on the outer surface of 
 the confining flask, and with such a practical demon- 
 stration we are compelled to admit the fact as stated. 
 
 Heat. While this water at the surface may be cold, 
 we know from the evidence of borings and mining 
 works that the temperature increases with depth from 
 that point near the surface at which it remains sta- 
 tionary through summer and winter alike, so that in 
 the Comstock lode, at the 2,300-ft. level of the C. & C. 
 shaft, the thermometer registered about 150 F., and 
 at the 3,000-ft. level of the Yellow Jacket shaft 170. 
 There is no difficulty in imagining this temperature 
 increasing to the boiling point of water (212) and 
 rising greatly higher, until it becomes so intense that 
 the water may be said to be (l white hot." This heat 
 is not the product of actual fires. It may be partly 
 caused by chemical action, but is more extensively 
 due, in all probability, to the pressure on the earth's 
 crust caused by its steady and constant contraction as 
 it cools, and to the friction from the wrinkling move- 
 ments, The rocks become hot during compression and 
 movement and impart their heat to the contained 
 water, which, aided by hydrostatic pressure, brings 
 it to the surface and it is dissipated in hot springs; 
 or, if such a vent is not made, by volcanic eruptions, 
 or the intrusion of lava into upper and colder strata. 
 
 Solution, Transportation and Deposition. We are 
 now prepared to understand the action of water in the 
 subsequent processes. We have the waters penetrat- 
 ing the rocks everywhere, the cooler waters descend- 
 ing, the heated ones tending to rise, or being forced 
 
HO PROSPECTING AND VALUING MINES. 
 
 to the surface along the lines of least resistance, such 
 as the fault fissures, by the pressure of other waters or 
 steam. 
 
 The ability of water to decompose rocks depends on 
 the presence of carbonic acid and alkaline material 
 such as the carbonates of soda and potash, and its 
 solvent powers are increased with a rise of tempera- 
 ture. Its first carbonic acid is derived by rain water 
 from the atmosphere, and the moment it touches the 
 earth it begins its work of decomposition and rear- 
 rangement, picking up and dissolving one mineral and 
 depositing another. Water traversing an open fissure 
 would thus leave a portion of its contents on the walls, 
 both sides alike, as it gradually cooled in its ascent, 
 just as sugar candy will crystallize out of the sugar 
 solution as it is cooled or evaporated, the process of 
 cooling producing the same result as that of evapora- 
 tion, in both cases the liquid being unable to carry so 
 great a load drops it at the first opportunity. In this 
 manner have veins like those of the Wheal Mary Ann 
 lode in Cornwall been formed (pi. 7, fig. 4), a, being 
 chalcedony (silica combined with water), b, glassy 
 quartz terminating in crystals; c, galena; and the 
 central core d, chalytite (carbonate of iron), the depo- 
 sition on both walls being similar and indicating the 
 origin of the minerals. The change in the deposited 
 mineral maj' have taken place either because of the 
 exhaustion of the locality from which it had been col- 
 lected by the water, or from such divergence in the 
 course of the underground flow by disturbances like 
 earthquakes that the material was drawn from a new 
 series of rocks. A similar incrustation of small cavi- 
 ties by waters abounding in silica has formed agates, 
 the banding being due to the changing presence of 
 the coloring material. Compact and close-grained as 
 these agates may seem, they are in reality porous, for 
 it has for centuries been a common practice to boil 
 them in suitable materials to increase the brilliancy of 
 
FILLING OF MINERAL VEINS. Ill 
 
 the coloring of the bands, the change being due to the 
 partial absorption of the material with which they 
 have been treated. When the cavity has not been 
 completely filled, it is either left with a smooth sur- 
 face of chalcedony (which does not crystallize) or 
 lined with crystals of quartz, calcite, etc. In such 
 manner also have opals and other minerals been intro- 
 duced into the oval cavities of basaltic lavas, and thus 
 we have also an explanation of how minerals can be 
 deposited as crystals on the top of each other by just 
 such changes in the character of the circulating waters. 
 Source of the Ore. The source of the minerals thus 
 deposited is to be found in the country rocks of the 
 region, mainly the eruptives, which, as we have seen, 
 contain nearly all, and probably would be shown to 
 contain quite all, of those known; or even from the 
 secondary or stratified rocks derived 'from older 
 igneous rocks, into which the mineral constituents of 
 the latter must unquestionably have been carried dur- 
 ing their deposition as sediment. That lavas have 
 been deprived of their valuable mineral constituents 
 in this way is fairly proved by the experiments of 
 Prof. Becker and Dr. Carl Barus, on the Comstock. 
 The hanging wall of that lode is diabase (in Virginia 
 City), known by the miners as "blue porphyry/' a 
 term which well expresses its appearance when freshly 
 broken. The Sutro tunnel has exposed the structure 
 of the east country (that is, on the hanging wall side) 
 for more than three miles, and developed a series of 
 bands showing plainly the results of solfataric action 
 (by heated waters), with alternating bands of hard 
 blue porphyry. Outside of, and next to the lode, the 
 rock is hard and suggestive of no change, except by 
 the presence of iron pyrites, which is nearly always a 
 product of decomposition, but under the microscope 
 it becomes evident that extensive changes have taken 
 place in it. Its crystalline structure has been modi- 
 fied, the hornblende and augite (silicates) have been 
 
112 PROSPECTING AND VALUING MINE8. 
 
 altered, pyrite Laving been made out of their iron, 
 and the silver which is present in them further away 
 from the lode has disappeared, the natural conclusion 
 being that it has found its way into the lode through 
 water. 
 
 Form of Deposit. All veins were not formed in the 
 manner described as occurring at the AVheal Mar} r Ann 
 lode and others similarly constituted. This presup- 
 poses an open fissure, and it does not seem possible 
 that all fissures in which veins have been formed re- 
 mained open during the process. In many it is plain 
 that such was not the case, because they show no true 
 walls, as in the Great Flat lode, Cornwall (pi. 7, fig. 
 5, and pi. 6, fig. 3), where the ore B is frozen to the 
 dike A, and there is only one wall; or in pi. 6, fig. 1, 
 where the masses are lenticular and not connected 
 with each other (Keystone mine, Cal.); or in pi. 6, 
 fig. 2, where there is no trace of banding, and the 
 hanging wall shows many feeders or stringers not 
 seen on the foot wall. The maintenance of an open 
 fissure in the case of such a structure, as pi. 2, fig. 2 (a 
 generalized cross section of the Comstock lode in Vir- 
 ginia City), would have been an impossibility for the 
 three or four miles of its length, the foot wall having 
 a dip of only 40; but it is equally plain that a slight 
 sliding of the hanging wall on the foot would produce 
 just such cracks as a, b, c, d, accompanied by an im- 
 mense amount of broken material. In many such cases 
 there is no true gangue, the ore occurring in the orig- 
 inal country rock, decomposed it is true, in bands or 
 stringers more or less parallel to the walls, or strike 
 of the rocks which have undergone decomposition, but 
 fading out into the unaltered country rock on either 
 side as at the Great Flat lode, or only on one side, as 
 in pi. 6, fig. 3; while in fig. 1 there is one true wall at 
 the contact line. In these cases we can only account 
 for the presence of ore on the supposition that as the 
 percolating water dissolved and carried away the par- 
 
FILLING OF MINERAL VEINS. 113 
 
 tides of the rock it left in their place particles of ore, 
 simply making an exchange, and it can easily be 
 understood how this substitution would go on most 
 rapidly and most extensively in those portions of the 
 fissure which had been most shattered during its forma- 
 tion, as the material would have been more largely 
 ground into powder at such points, not only allowing 
 more water to find its way through those portions, but 
 presenting vastly greater surfaces to the action of the 
 water. Thus a cube with faces 1 in. square has a 
 surface as 6 to 1 of bulk, while a cube with faces 2 in. 
 square has a surface of only 3 to 1 compared with bulk. 
 It is at such places that the largest deposits have taken 
 place, and it is thus that "horses" have usually been 
 formed in the lodes; not by masses falling into an 
 open fissure, but by the water circulating through 
 crevices, completely surrounding a block of country 
 rock. We constantly find pieces of country rock in 
 veins completely inclosed in ore, and these are only 
 horses on a very small scale. The Savage mine, at 
 Virginia City, afforded abundant specimens of min- 
 eralized porphyry, suggesting this origin, and those 
 of Monte Cristo, Wash., offer many more illustrations 
 which are totally inexplicable on any theory of large 
 open fissures. Many such veins have acquired slicken 
 sides and gouge by subsequent movements of the rocks, 
 which would naturally follow such lines of weakness, 
 and may even have undergone a partial refilling and 
 reconcentration of their own constituents, some por- 
 tions having been impoverished to enrich others. That 
 such movements have taken place is shown by the 
 crushing of the quartz in some of the larger bodies on 
 the Comstock lode, so that it was known to the miners 
 as "sugar quartz." 
 
 These examples suggest an explanation which will 
 account for nearly all cases of vein structure, and at- 
 tention in the field will show how beautifully the 
 cycle of changes is constantly in progress, beginning 
 
114 PROSPECTING AND VALUING MINES. 
 
 with the earliest fracturing of the rocks and the first 
 rainfall, with no cessation to the present time. 
 
 Rationality of Natural Processes. A moment's 
 thought will show that under any circumstances some 
 such results as have been outlined must have been the 
 outcome of the surface changes of the earth. Even 
 had the original veins been solid masses of gold, 
 silver, copper, etc., their contents would, as they were 
 worn away, have been scattered far and wide through 
 the rocks which were formed out of the earth's first 
 crust, even if that crust itself did not contain them, 
 and the condition of the rocks which we have pictured 
 would have been one of the first results of erosion, 
 and the formation of veins by segregation or substitu- 
 tion must have commenced even in those early days, 
 by the workings of the laws of chemical affiuit3 r , which 
 imply the abandonment by one element of its associate 
 in a compound when it meets with another which is 
 more to its liking under suitable conditions for mak- 
 ing the exchange. 
 
 How easily these changes are effected may be seen 
 in the occasional action of metallic compounds in the 
 cabinet. Just as the iron pyrite crystals, so abun- 
 dant in some of the gravel mines of California (pi. 11, 
 fig. 3, shows a petrified tree covered with them), drop 
 to pieces and decay with extraordinary rapidity, so 
 specimens of pyrite of the bronze-colored variety from 
 the Glacier mine, Monte Cristo district, Wash., after 
 remaining in the writer's cabinet only two months, 
 were entirely decomposed, the pyrites having absorbed 
 moisture, which combining with the contained sul- 
 phur had produced sulphuric acid, which in its turn 
 had combined with the gangue of the specimen (par- 
 tially altered porphyry), forming glistening salts and 
 rough concretions, not only on the specimen originally 
 attacked, but on the adjacent ones which happened to 
 be in contact with it, however slightly. The amount 
 of moisture absorbed was so great that what remained 
 
FILLING OP MINERAL VEINS. 115 
 
 of the specimens could not be handled without stain- 
 ing the hands black. On seeing the change the writer 
 remembered extracting from the same vein, in a prev- 
 ious year, samples with the same appearance, having 
 undergone the same changes in place. If then the 
 small amount of moisture which is present in a dwell- 
 ing room can effect such changes, we are at no loss to 
 understand how much greater ones can be effected by 
 nature in her vast underground workshops, with her 
 absolute disregard of the element of time. 
 
 Ore Deposit* in Limestone. In a somewhat similar 
 way have the greater portion of the deposits in lime- 
 stone been formed, percolating waters eating out pas- 
 sages and chambers, which have been subsequently 
 filled with iron, lead or zinc ores by the waters trav- 
 ersing them. The ability of water to excavate caves, 
 such as the Mammoth Cave in Kentucky, and hundreds 
 of others in all extensive limestone regions, is so well 
 known as to require no further comment, except that 
 the most remarkable feature about them is their sub- 
 sequent filling with large bodies of mineral, usually 
 of only one or two kinds, much less complex in their 
 constitution than the filling of veins; which suggests 
 a different, probably cooler, condition of the percolat- 
 ing water. Such deposits are of the most irregular 
 shape, due to the vagaries of the water which hol- 
 lowed out the chambers, and when the walls are 
 reached they may generally be scraped clean, as the 
 mineral does not usually penetrate the limestone to 
 any depth. PI. 6, fig. 8, is a sketch of such a deposit 
 formed in limestone, on the bedding planes and joints, 
 and controlled only by the lines of flow of the water, 
 as indicated by the arrowheads. Such are the deposits 
 of Wisconsin and Illinois. Fig. 4, same plate, shows 
 the limestone traversed by the dike B, and the arrow- 
 heads the possible direction of the water flow, which 
 if descending, as at A, might form ore bodies as shown 
 in black, or if ascending, as at (7, either as hot or cold 
 
116 PROSPECTING AND VALUING MINES. 
 
 water under pressure would present a similar structure. 
 Fig 7 shows the structure of the veins at Tombstone, 
 Ariz., being successive strata of slates S, limestone, L, 
 quartzite, Q, and dolomite (magnesian limestone) D, 
 traversed by the quartzose fissure veins A.B, which 
 are connected in the limestone by the flat bodies of 
 rich lead ore, C. In pi. 1, fig. 2, we have at Leadville, 
 Colo., lead ores lying between the limestone flour, the 
 deposits being nearly horizontal, and porphyries for 
 a roof. 
 
 On pi. 7, fig. 2, we have hematite B, deposited in 
 cavities of the mountain limestone A, at Ulverstone, 
 England. Subsequent to the deposition of the ore it 
 is evident that a further portion of the limestone was 
 dissolved by waters free from iron, forming a later cave 
 which was filled with the clay G, the whole being 
 probably partially worn away before the covering of 
 dirt D was laid down at a much later date. In fig. 3, 
 same plate, we have a similar formation at Al ten berg, 
 Germany, only calamine (silicate of zinc) takes the 
 place of the hematite in the former illustration. B is a 
 body of limestone, lying between the slates A, the 
 zinc ore D filling a cavity of erosion, and the clay C 
 filling a cavern of later date formed after the deposi- 
 tion of zinc ore had ceased. 
 
 In most such cases it is probable that the filling 
 took place by waters percolating through rocks of later 
 formation, lying above the limestone in which the 
 caverns were formed, from which they abstracted the 
 iron and zinc, only to redeposit them when presented 
 with a more tempting morsel in the shape of lime. 
 
 Ores Possibly Derived Directly from the Sea. 
 Most chloride and bromide ores of silver and lead 
 are found near the surface, in the joints of limestones 
 and quartzite; it is very probable that such rocks have 
 derived the ore found in them from sea water, when 
 they were a portion of the ocean bottom. In Arizona 
 there are many occurrences of these ores in localities 
 
THE FILLING OF MINERAL VEINS. 117 
 
 where such a condition has been possible, there being 
 evidences of the former existences of an ancient inland 
 sea. A similar explanation is advanced to account for 
 some gold-bearing conglomerates, in which the gold is 
 supposed to have been precipitated from the ocean, 
 near shore. By a secondary process the gold sparsely 
 disseminated in mud beds at the bottom of the sea 
 might be concentrated in quartz veins, traversing the 
 shales and slates formed by the consolidation of these 
 beds. The ocean-formed ore bodies would, if derived 
 directly, be beds or impregnations and not true veins. 
 
 Electro-chemical Action. Around many of these 
 phenomena, as around so many of the operations of 
 nature, there hangs a suspicion of the intervention of 
 electricity. The action of electrical currents is forci- 
 bly suggested in the case of native copper mixed 
 with native silver, or of gold crystals deposited upon 
 horn silver; but even if such an agency was active in 
 their production there must have been a previous 
 leaching of other rocks to provide the solutions from 
 which the metals were reduced and crystallized. 
 
 A Cycle of Perpetual Change. That operations such 
 as we have been describing are constantly going on in 
 nature, and that no extraordinary processes need be 
 invoked to account for the phenomena we see, is plainly 
 evident from the changes which take place in the 
 outcrops of veins and elsewhere. We constantly find 
 incrustations of various salts, such as alum and those 
 of soda and potash, forming on the sides of caves, and 
 even of other minerals on the walls of deserted mines; 
 we secure copper from the waters discharged by copper 
 mines or mines of coppery iron pyrite by allowing it 
 to run over scrap iron, which is destroyed by the acid 
 in the water and copper released ; the pyrite in the 
 outcrop of veins is decomposed under the joint action 
 of air and water, leaving a deposit of rusty iron- 
 stained gaugne, while the sulphuric acid percolates 
 downward to produce other changes; we find surface 
 
118 PROSPECTING AND VALUING MINES. 
 
 pyrites likewise decomposing, parting with their sul- 
 phur and iron, only to combine with oxygen, and form 
 the red and black oxides of copper, which are richer 
 than the original ore, and in fact are merely concen- 
 trates of ores which may even be too poor to work 
 when the limits of the changes are reached, which is 
 usually where the presence of permanent water pre- 
 vents contact with the air. We also find that many 
 carbonates of lead have a core of galena, which is the 
 sulphide, and know that the conversion has taken 
 place since the deposition of the galena ; and if we 
 look carefully around us we will meet everywhere with 
 alterations going constantly forward. Brought up 
 from the unknown interior of the earth by lavas, the 
 minerals are collected from them into veins, only to 
 be again scattered as the veins are worn away in the 
 general destruction of the earth's surface, and mingled 
 with the fragments of the lavas in sedimentary de- 
 posits, which, as we have seen, ultimately return to 
 granite, only to be intruded into the overlying strata, 
 the wearing away of which uncovers the granite, and 
 the circle is completed. Formation, rearrangement, 
 destruction, reformation and return to the original are 
 the perpetual cycle of the changes in veins, and not 
 only of them but of the rocks in which they are con- 
 tained. 
 
 Local Limitations. These views afford a natural 
 explanation of the reason why mineral veins are con- 
 fined to certain regions and are not found in all areas 
 of dislocation. We have no knowledge of the appear- 
 ance of the original crust of the earth, as it was 
 formed under conditions which we can never hope to 
 see, but it is evident that all minerals, except meteor- 
 ites, now upon the surface of the globe, in whatever 
 condition, must have been derived either from it or 
 from rocks which have been ejected through it. At 
 the moment these began to decay we have the com- 
 mencement of the whole stratified series, through 
 
THE FILLING OF MINERAL VEINS. 119 
 
 which, in some form or other, all the mineral constit- 
 uents of the original rock must be scattered, accord- 
 ing to the size of the particles, except those which 
 were perfectly soluble; but always on lines descend- 
 ing seawards. In the course of time these sediments 
 would be again brought to the surface, to be again 
 worn away into new sediments, mixed with the debris 
 of a new series of eruptive rocks, the process being 
 repeated with ever-increasing complexity, but with a 
 constant increase in the metallic contents of the crust, 
 if such were brought from below by the eruptive rocks 
 from time to time. 
 
 But just as soon as fracturing began, and with it 
 the circulation of heated waters, the concentration of 
 the minute particles into veins would begin, which as 
 they in turn were eroded would furnish particles of 
 larger size to the sediments, and in time these might 
 contain sufficient mineral to form large deposits when 
 concentrated by the circulating waters, even at long 
 distances from the seat of the original eruptive rocks 
 from which the mineral was derived. Such sediments, 
 still retaining the mineral fragments, like the lead 
 and copper-bearing shales and sandstones, can be con- 
 ceived to be still forming. 
 
 We can now see why all fractured regions are not 
 metalliferous. There must have been an .original area 
 of eruptive or volcanic rocks to start the metal-bearing 
 series, for without this no amount of folding or dislo- 
 cation could have produced an ore vein. 
 
 We can also understand the spotted or pockety 
 character of many veins; and why there should so 
 often be in a district one strong "mother" vein, as 
 the main fissure would offer more unimpeded channels 
 for the circulation of water than the smaller lateral 
 crevices; and why veins of different geologic age in 
 the same district should be filled with different min- 
 erals, as the source from which the first series was 
 filled may have been exhausted before the formation of 
 the next. 
 
CHAPTER VII. 
 INFLUENCE OF ROCKS ON VEIN FILLING. 
 
 IT is evident that if there is any relationship be- 
 tween ore minerals and rocks, or if, in other words, 
 the useful minerals are more particularly found asso- 
 ciated with some particular rock in preference to 
 others, the knowledge of the facts would be of great 
 value to the prospector, for when he had gained an 
 idea of the rocks of any particular district he would 
 have a general idea of the minerals which he was 
 likely to find there, and could familiarize himself with 
 their appearance, from books or otherwise, and 
 not only know what to look for, but how and to recog- 
 nize them when found. 
 
 The following imperfect table, compiled from recog- 
 nized authorities, while far from being as complete as 
 could be wished for, undeniably shows that there is 
 such an association of minerals with certain rocks, the 
 reasons for which we may not at present thoroughly 
 understand, but which is not only of interest but of 
 practical importance. 
 
 The greatest difficulty in preparing such a list is to 
 give equal prominence to all parts of the subject, be- 
 cause while a certain ore maybe found at two separate 
 localities in two different rocks, it may be of no 
 especial value in one of them and of vast importance 
 in the other. It is almost impossible to correlate such 
 differences. One might quote 20 mines in a single 
 district, all having practically the same character, 
 and only one in another district of different rock 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 12 1 
 
 structure but producing the same metal, thus giving 
 undue prominence to the former mode of occurrence; 
 and it is not always possible to estimate the "personal 
 equation" in the various published accounts, which 
 phrase is understood to include the amount of knowl- 
 edge and accuracy of the writer and preconceived 
 theories unconsciously coloring his views. 
 
 To overcome these difficulties, and yet keep the 
 table within reasonable limits, a limited selection of 
 cases where the information was full enough has been 
 made from the literature of the subject. The selec- 
 tions are for districts, not individual mines, and though 
 insufficient for a thorough scientific discussion, will 
 be sufficient for our purpose. It does not include iron 
 ore, as that is chiefly found in bedded deposits, not 
 subject to the same influences; nor the minor minerals, 
 such as nickel, cobalt, antimony, bismuth, etc., as 
 they are usually the accompaniments of other ores, 
 and do not form the prominent or controlling mineral 
 of the deposit which imparts to it its positive char- 
 acter, although these may have a preference for one 
 mineral rather than another, and occur most frequently 
 in combination with it. 
 
122 PROSPECTING AND VALUING MINES. 
 
 Remarks. 
 
 111 
 i 1 
 
 g Jg'tf o 
 
 * ;<ti i 
 
 i i a rf ! 
 
 & jtrf ii *i 
 
 > - s ^Sg -2^ 
 g-g-S ^^ 2-g 
 s fa* ^^ So 
 
 ^> > ^ QQ O 
 
 Black clay slates. 
 
 Talc and serpentine. 
 Talc and serpentine. 
 Quartzose and talcose schists 
 Chloritic, talcose and clay 
 
 schists. 
 Mica, talc, hornblende and 
 chlorite schists. 
 Mica and chlorite schists. 
 Mica schists and in sheeted 
 walls. 
 
 Quartzose schists no erup- 
 tive rocks. 
 Between laminae. 
 Schists broken through by 
 cVorite dikes. 
 
 i 
 
 I 
 
 i 
 
 : i^-d 
 
 B" 'SS 
 
 
 
 
 : : 
 
 : -o 
 
 9-, 3 
 
 
 
 
 ^ : : 
 
 Nagyag, Transylvania . . . 
 Sudbury, Ontario 
 Allison mine, Amador Co. 
 Thames district, New Zea 
 
 Telluride belt, Colo 
 Butte Co., Cal. 
 Berezovsk, Russia 
 Boulder Co., Colo 
 'ides WyonVg mine. Nevada Co 
 Soaprot mine CalaveraCo 
 Sent"nlmine,BoulderCo., 
 s Wermouth concesXHonc 
 
 . .. Keystone mine, Amador 
 Cal. 
 Siberia 
 Mariposa Co. , Cal 
 Peshaston Creek, Wash. . 
 e, galena Yavapai Co., Ariz 
 Berezovsk, Russia 
 
 i 
 
 1 
 
 c 
 a 
 C 
 
 Tomoh, Siamese Malay 'nS 
 Maryland 
 
 5 
 
 
 
 C 
 
 Tolema, South America. 
 Calaveras Co., Cal 
 
 Principal and Asso 
 Minerals. 
 
 9 
 & \\-\\ 
 
 I ! : i 
 
 M Hi ; :i 
 
 ":: : 
 
 .o.o..o. Ironpyrite 
 
 Ironpyrite 
 Ironpyrite 
 Iron pyrite,zincblend 
 
 i 
 1 
 
 I 
 
 > 
 \ \ 
 
 
 e rocks 
 
 1 
 
 II P tf 
 
 1 
 
 Trachyte 
 Diorite 
 Diorite 
 Andesite.., 
 
 Porphyry.. 
 Porphyry; 
 Porphyry... 
 Porphyry granite 
 Granite or gneiss. . 
 Granite or gneiss. . 
 Granite or gneiss. . 
 Granite line conta 
 
 Slates.... 
 
 ' 02 03 CO 
 
 05 4-S 4J -1-3 4^ 
 
 cp to co 02 a 
 
 02 CO CO 
 
 .23 .23 22 
 2 22 
 
 t> o o 
 
 O2 CC02 
 
 Schisms. . . . o . . 
 
 Schists 
 Schists and eruptiv 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 123 
 
 ks. 
 
 -S -S 
 
 a 
 
 i 
 
 & 
 2 
 
 ^ 
 Q 
 
 a 
 
 Q 
 H 
 
 O 
 
 ^ 
 
 o 
 
 III 
 
 PQ 55 
 
 ^j 
 
 3 
 
 o-o 
 O 
 
 |;i 
 
 ii 
 
 3 
 5 
 
 
 
 PH 
 
 1 
 
 - 
 
124 PROSPECTING AND VALUING MINES- 
 
 ri 
 
 Js-ss&i o| 
 Is 1*4*1 jJl 1 si 
 
 1 .S.'SS-S'alSr $0 ^ 
 
 <y 5 
 
 00 
 
 Silver sulphide 
 Galena, zinc 
 manganese. 
 
 " 
 
 6s 
 
 phid< 
 ial sil 
 
 1 -8 
 
 I ^ 
 
 sis b 
 
 S^LsL >' 
 
 .- S^ &5 ^^ - 
 
 ? ^yo a 3 pp 
 
 ^ ^^^ ^g 
 
 InO O02 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 125 
 
 
 pJie!iMJiliffll 
 
 
 9eg9Sea 
 
 o o . 
 
 i 
 
 a 
 
 02 
 X 
 
 s 
 
 .i 6? 
 
 opO 
 
 
 ii 
 
 si 
 
 c ^ 
 
 II 
 
 S 23 in 55 585 
 
 a^ 
 
 ?s 
 
 & 
 
 t t 
 
 JO! O! 
 <D o; 
 S P P P 
 
 I 3 SS .sil 
 
 a><r> 
 .-S.-S 
 
 N (S3 
 
 rr 
 
 o* 
 
126 PROSPECTING AND VALUING MINES. 
 
 Remarks. 
 
 +j 
 
 1 
 
 
 Q 
 
 Vlica slates. 
 Jlay slates. 
 
 Associated eruptive rocks. 
 Mica schists and gneiss, 
 traversed by granulite 
 dikes and capped with ba- 
 salt. Lodes cut the dikes. 
 
 1 
 
 a 
 
 I 
 
 c3 
 
 s 
 
 s"' 
 
 0" 
 
 r^ 
 
 Conglomerate foot wall, 
 n ash beds of amvedalordal 
 
 diabase, 
 n "trap. 11 
 n "trap. 11 
 Denticular beds in diorite. 
 [n fissured zones rhyolite 
 
 near, 
 n beds, 
 ^eins in gneiss and quartzite. 
 Sfear contact of graywacke 
 and diorite, or in the dio- 
 rite. 
 Various schists associated 
 
 
 
 
 
 
 
 
 
 
 
 ; 
 
 a 
 
 3 
 
 
 
 
 * ' 
 
 4* 
 
 
 02 
 
 
 
 1? 
 
 Tombstone, Ariz. 
 Salt Lake, Utah.. 
 
 Maine 
 Connecticut 
 Bohemia 
 Cornwall 
 Monte Cristo, Wa 
 Pontgiband, Fran 
 
 j 
 
 03 3 . 
 
 0^3 t- 
 
 11 
 
 S - a 
 
 '.2 
 
 ;| 
 
 '-3 tg 
 gOttM 
 
 Fahlun, Sweden.. 
 Maine 
 Sudbury, Ontario 
 
 Canelton. Quebec 
 
 ^ 
 
 
 : : : :& 
 
 
 1 
 
 
 
 W CO 
 
 i :: 
 
 % : : : 
 
 > 
 
 33 fV> 
 
 
 
 Principal and ^ 
 Minera 
 
 LEAD-SlL 
 
 . Silver, gold 
 Silver 
 
 . Zincblende and cc 
 
 . Silver, zincblende 
 . Silver 
 
 . Ziucblende and si 
 
 . Silver, zincblend 
 pyrite. 
 
 COPPEI 
 
 . Native . . 
 
 09 
 
 C 
 
 ii 
 
 02 33 
 
 ii 
 
 
 11 
 
 
 
 
 
 
 
 Jb 
 
 
 
 
 : : :S 
 
 
 1 
 
 C i^ 
 
 sa 
 
 
 "c3 
 
 & 
 
 fill 
 
 !|| | 
 
 
 ii 
 
 S'E3 
 
 
 I 
 
 I 
 
 O D 33 ^3 
 
 ^.S: ^ s 
 
 j|f i 
 
 
 11 
 
 o> ta t cc - -M 
 
 "fcib 
 
 I 
 
 -2 
 
 60 
 1 
 
 ^ aaaa 
 
 "3 '3 ft g 
 S ^ 2 E 
 cow K 
 
INFLUENCE OF HOCKS ON VEIN FILLING. 
 
 1 
 
 n or near to the Carbonifer- 
 ous limestone. Another 
 
 S S 
 
 ft c 
 
 3 I 
 
 |co 
 
 "3 ' z 
 
 *5 
 
 ; l 
 1^ 
 
 IS 
 
 gil 
 
 i i w p 
 
 i ^ in n ii 
 
 2 ii if i if si. 
 
 S . rtlllf |8^2 
 s g.3lll|: M VF 
 
 | |3Sg .5| <^-sJ 
 
 >! |1s|l|ii jiii 
 
 :S laStSrii Sifll 
 
 >! J'S^fi-a-'SS SgSSS 
 
 ) QPQ I^M PQcC 
 
 Small veins, 
 n granitic gneiss, 
 n lime at contact of dikes 
 cutting lime and granite, 
 ncluding dolomites, 
 ncluding dolomites, 
 ncluding dolomites. 
 
 
 
 
 
 
 i 
 
 tjj 
 
 I s 
 
 il 
 
 oo 
 
 i 
 1 
 
 4 
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 S 
 
 >> : .S T 
 
 ^ I 
 
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 5 j?T3 5 ft M 
 " 2 5 -^ " ^ 
 
 ^ r/^ O CC J-i 
 
 1 dj"* w.s * a ^ 
 
 2 5 o S 3 o^ o" 
 5 OS55 HP3 OJO C 
 
 .... Maryland 
 .... Ammerberg, Sweden 
 .... Southwest N. Mex 
 
 .... England and Belgium 
 Connecticut 
 .... Wis., Mo., Iowa and Ills... 
 
 Associate 
 Is. 
 
 
 
 
 
 ^ cs 
 
 T3 *-< 
 
 ll 
 
 i i WH 
 
 w '. 
 
 H : : 
 
 o w co 
 rl 9 P 
 
 
 : : : : : : S : 8 : 
 
 CO P< fcn 
 
 :fe 
 
 d : 
 
 a Ih Ml 
 
 f 
 1 
 
 ( 
 
 Oxidized or 
 o . . . Oxidized 01 
 
 
 S =S 8^3 
 
 T3 I Q CO 73 Oj 
 
 i!J ll! 
 
 o ;O t>^;o 
 
 111 
 
 1 
 
 I 
 
 
 o 
 
 
 81: : : i : : : 
 
 : :a : : 
 8 i : : 
 
 I ! : " ; 
 
 & 
 
 Granite lime 
 Limestones . . 
 
 Limestones . . 
 
 w : : : : :-g-g 
 
 :^3coco coco wSS 
 CCDO) CDCD <I>5353 
 
 ^oo oo oSS 
 
 | ^j*3 4j4j *^^^ 73 
 
 Qfl_; flfl flflP "^ 
 
 S : : : 
 
 1 $$$ 
 &* c a a 
 
 000 
 
 Jit 111 
 
 s ... 
 
 OOPn JJJ 
 
128 PROSPECTING AND VALUING MINES. 
 
INFLUENCE OF ROCKS ON VEIN FILLING, 129 
 
 il 
 
 0)^3 
 >0 
 
 *%S 
 
 ? Si's 
 
 s|SI 
 
 ;- H^a.S 
 O o *- f-> 
 
 SSrf .S< 3 
 
 I^' 3* ! 
 
 o>^? <u <v 3 
 
 WO 
 
 i ill! 
 
 Ill 11 
 
 o o .o o .2 .2 .2 .2 .2 
 
 III 
 T iu i* 
 
 ||| 
 = j| J 
 
 . . . . 
 
 OOO OO^ O^ O;g O - 0*^ 
 
 Pgs SS BsSsS^BsS 
 
130 
 
 PROSPECTING AND VALUING MINES. 
 
 In the following table the eruptive rocks have been 
 necessarily placed together, because while trachyte 
 has 4 mentions, diorite 6, andesite 5, rhyolite 7 and 
 basalt 5, there are 25 notices of simply igneous rocks 
 prophyry, trap, or other indefinite names, which 
 cannot be classified. 
 
 CONDENSED TABLE OF ROCKS AND ASSOCIATED METALS. 
 
 Metals, 
 
 Eruptive and Intrusive. 
 
 Sedimentary. 
 
 Alone. 
 
 Associated with 
 
 Alone. 
 
 Contacts. 
 
 1 Granite, Gneiss. 
 Syenite. 
 
 Eruptive. 
 
 Gneiss, Granite, 
 Syenite. 
 
 Sandstone, 
 Quartzite. 
 
 Schists. 
 
 Shales. 
 
 Limestone. 
 
 Sandstone, 
 Quartzite 
 
 a 
 
 X 
 
 Shales. 
 
 Conglomerates. 
 
 Limestones. 
 
 Serpentines. 
 
 Lime and 
 Shales. 
 
 Lime and 
 Quartzite. 
 
 j Slates and 
 M 1 Sandstones. 
 
 Gold 
 
 7 
 
 1 
 1 
 
 2 
 
 5 
 
 1 
 
 1 
 
 1 
 
 ( .) 
 
 1 
 
 2 
 
 1 
 
 
 
 
 
 
 
 
 
 
 Silver 
 
 2 
 
 s 
 
 5 
 
 2 
 
 i 
 
 1 
 
 1 
 
 2 
 5 
 
 3 
 
 
 1 
 
 
 1 
 
 
 
 
 
 Lead 
 
 2 
 
 4 
 1 
 
 *2 
 2 
 
 4 
 2 
 f> 
 
 
 1 
 
 3 
 1 
 
 .... 
 
 
 3 
 q 
 
 4 
 
 
 
 8 
 
 
 
 5 
 
 Zinc 
 
 
 
 
 
 1 
 
 
 
 Tin 
 
 5 
 
 1 
 
 
 
 
 
 
 
 2 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 7 
 
 
 
 
 
 1 
 
 
 
 
 
 
 
 
 
 
 
 2 
 
 
 
 
 
 
 
 
 
 
 6 
 
 
 
 
 tl 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 By further condensation we have the following table : 
 
 COUNTRY ROCKS BROADLY GROUPED. 
 
 Metals. 
 
 Granite, Gneiss, 
 and Syenite. 
 
 Sedimentary 
 Rocks. 
 
 Associated with 
 Eruptive Rocks. 
 
 Totals. 
 
 Gold. 
 
 3 
 
 15 
 
 16 
 
 34 
 
 Gold and silver.. 
 
 
 1 
 
 2 
 
 3 
 
 Silver 
 
 2 
 
 5 
 
 11 
 
 18 
 
 Lead 
 
 3 
 
 16 
 
 
 
 25 
 
 Copper 
 
 3 
 
 11 
 
 7 
 
 21 
 
 Zinc 
 
 2 
 
 5 
 
 1 
 
 g 
 
 Tin 
 
 5 
 
 2 
 
 1 
 
 $ 
 
 Chrome 
 
 
 7 
 
 
 7 
 
 Manganese 
 
 1 
 
 2 
 
 
 2 
 
 Mercury 
 
 
 4 
 
 6 
 
 10 
 
 
 
 
 
 
 
 19 
 
 68 
 
 50 
 
 137 
 
 * Probably remains of beds of lime, i All in belts of hot springs. 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 131 
 
 The rocks in the foregoing tables may be further 
 classified according to the amount of silica or quartz 
 which they contain, into three groups: 
 
 \. Highly silicious: Granite, gneiss, mica schists, 
 sandstones, conglomerates, quartzites, eruptive rocks, 
 and some limestones. 
 
 '2. Moderately silicious: Chlorite, talc and clay schists 
 and shales, conglomerates in part, and some lime- 
 stones. 
 
 3. Scarcely silicious: Limestones and dolomites. 
 
 Examining the metals in the foregoing list we find 
 in the case of 
 
 Gold. Twenty-six occurrences in rocks abounding 
 in quartz (silica) out of the 34 localities, and in some 
 of the remainder the same conditions probably exist, 
 as many shales and conglomerates are highly silicious. 
 Only one occurrence is noted with limestone and in 
 this case the foot wall of the deposit is granite. 
 
 Gold and Silver. All three occurrences are in rocks 
 abounding in silica. 
 
 Silver (aside from silver-lead ores which are classed 
 as lead) occurs in 13 very quartzose rocks out of 18 
 instances, and the remaining 5 are probably silicious, 
 as many limestones are highly silicious. 
 
 Copper also occurs with 18 very quartzose rocks, 
 and probably with 19 out of the 21 localities, if not 
 more, as the Clifton deposits are differently described 
 by two writers, and the other limestone locality may 
 carry much quartz. 
 
 Lead, however, occurs in the quartzose series in 
 only 10 out of 25 localities, the remaining 15 being in 
 association with limestones, while some of the former 
 may have lime to some extent as a minor constit- 
 uent. 
 
 Zinc shows 6 out of 8 times as an associate of lime- 
 stone and only twice in the quarfczose group. 
 
 Tin. All 8 of the occurrences are in quartzose 
 rocks. 
 
132 PROSPECTING AND VALUING MINES. 
 
 Chrome. All 7 localities are in serpentines, usually 
 associated with gneissic or hornblendic rocks. 
 
 Manganese is associated with both extremes of rock. 
 
 Mercury. All 10 localities are in highly metamor- 
 phosed rocks of various kinds, but nearly all are asso- 
 ciated with recent eruptive rocks and hot springs. 
 
 The relative importance of these occurrences is best 
 tested by the output commercially of the different 
 metals. Tested in this way, the highly silicious 
 rocks produce the bulk of the gold, silver, copper and 
 tin ; the non-silicious or true limestone rocks, the 
 bulk of the lead and zinc, and rocks which on decom- 
 position yield both silica and lime, give complex ores 
 of gold, silver, lead, copper, zinc, tin and manganese, 
 with many other less prominent metals. 
 
 Metals Associated With Each Other. Gold and 
 silver are so intimately associated in nature that all 
 gold may be said to contain some silver; and most 
 silver ores carry gold, from mere traces up to impor- 
 tant values. Gold containing a large proportion of 
 silver is pale in color and is sometimes called "elec- 
 trum ;" while some native gold-silver alloys are almost 
 white. 
 
 Lead and silver are also so related that lead ores as a 
 rule carry some silver, if only a trace, and from that 
 up to large amounts in value, though not in bulk, 
 without any special change in their outward appear- 
 ance. 
 
 Lead and zinc are also intimate associates, as are 
 also lead and antimony. 
 
 Copper and silver, or copper, silver and gold, often 
 go together. 
 
 Iron and manganese, or iron and chrome, are fre- 
 quently associated. 
 
 Nickel and cobalt are closely related, both chemi- 
 cally and in occurrence. 
 
 Arsenides and antimonides of other metals are 
 often found together, and either or both with sul- 
 phides. 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 133 
 
 Country Rock and Gangue. The ore minerals proper 
 usually compose only a fraction of the whole 
 vein filling, the gaiigue minerals being present in 
 larger, often very much larger quantity. The rocks 
 through which the underground waters pass must con- 
 tain material suitable to form this gangue silica for 
 the quartz, lime for the calcite, fluorine for fluorspar, 
 sulphur for the sulphate minerals, etc. The gangue 
 minerals are closely related to the metals and true ore 
 minerals (as quartz to gold, calcite to galena, etc.); 
 hence the connection is really threefold country rock, 
 gangue, ore. 
 
 Relation of Eruptives. While eruptive rocks are 
 frequent accompaniments of ore, they are not abso- 
 lutely essential to its presence either in the silicious 
 rocks of Otago, New Zealand ; or the sandstone reefs 
 of Bendigo, Australia, or the non-silicious limestones 
 of the Central States in America. In only 50 out of 
 137 cases are eruptive rocks mentioned in connection 
 with the ore deposits as being of possibly prior origin, 
 or about 36%, while in 68 cases, or about 50%, there 
 is no apparent connection of either eruptive rocks or 
 granite. Possibly eruptives existing in the neighbor- 
 hood of ore deposits, but not actually contiguous, are 
 sometimes overlooked or not reported. 
 
 There are cases in which the metal in the deposits 
 undoubtedly appears to have been derived from them. 
 But outside of these instances there are others where 
 the outbursts of eruptive rocks have simply produced 
 the necessary conditions of heat and fractured rocks, 
 furnishing waters of the requisite temperature and pro- 
 viding ample facilities for their percolation through 
 materials so crushed as to be easily soluble. 
 
 Similar results have been obtained in other places, 
 without the aid of eruptive rocks, by the enormous 
 pressure involved in the complicated folding which we 
 see in such cases as the sandstone reef at Bendigo, 
 Australia, or the abruptly folded strata in Nova Scotia, 
 
134 PROSPECTING AND VALUING MINES. 
 
 so that it would appear that any cause which will pro- 
 duce heated water and fractured rocks is sufficient to 
 furnish the conditions for vein filling, the material for 
 forming the deposit being drawn from any one or all 
 of the rocks indiscriminately through which the water 
 has been circulating, whether above, below, or along- 
 side, near to or at considerable distances from the 
 point of final deposit; and that this place of final 
 deposit is largely determined by the character of the 
 rock through which the water may be circulating at 
 the time it is compelled to part with some portion of 
 its mineral burden, and not by the character of the 
 cause which produced the fissures, or the nature of the 
 associated eruptive rock, unless the ore is deposited 
 in thi t rock itself. The following extracts strike the 
 keynote and indicate a line of examination which will 
 explain nearly all, if not quite all, the phenomena of 
 the association of minerals with each other, and the 
 rocks in which they occur. Speaking of the ore de- 
 posits in the Potsdam series of rocks in South Dakota, 
 Dr. F. B. Carpenter says: "These ores are in some 
 sections, almost exclusively gold-bearing; in others, 
 they carry partly gold and partly silver, and again in 
 other places the silver predominates." "It seems as 
 though the porphyry at Bald mountain brought 
 mainly gold ; at Buby basin, only a few miles distant, 
 gold and silver in nearly equal quantities (in value); 
 while at Galena, 12 miles distant, silver-lead predomi- 
 nated. That is, broadly speaking, gold predominates 
 in the quartzites, but gives place to silver as we ap- 
 proach the more calcareous portions forming the upper 
 parts of the Potsdam; while in the massive limestones 
 such ore bodies as are found, like the Iron Hill, carry 
 exclusively lead and silver, yet the porphyry is in all 
 instances the same." 
 
 Variations in the Mineral Solutions. But in following 
 up this line of argument we must remember that 
 all waters will not be charged with the same mineral, 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 135 
 
 or the same water always with the same mineral, as 
 their contents must vary with the nature of the rocks 
 from which they draw their supply, and consequently 
 they can only deposit what they have in solution for 
 the time being, and may carry that for long distances 
 for want of a suitable precipitating agent. They may 
 have only one or many minerals in solution, but at any 
 rate we are prepared to understand the occurrence of 
 gold in the joints of porphyry, of silver in the joints 
 of quartzite, of lead and silver in the seams of lime- 
 stone, and why the character of the ore should change 
 so suddenly when a vein passes from one series of 
 rocks to another, as for instance from a silver-bearing 
 galena with zincblende and iron pyrite in decaying 
 porphyries with lime feldspars, or a gold-bearing 
 arsenical pyrite in the underlying granite; from 
 copper in silicious slates to tin in a still more silicious 
 granite, where also the character of the mica (white 
 mica being common in tin-bearing rocks) appears to 
 have an influence, or to be, like tin, a result of the same 
 influence; or from deposits of galena in limestone to 
 barren material in the intercalated beds of " toad- 
 stone" (an ancient eruptive rock), as in the lead 
 deposits of Derbyshire, England. 
 
 Influence of the Country Eocks. The practical 
 miner, however, is not so much interested in the 
 scientific explanation of such sudden changes, but he 
 is very materially interested in the fact that they do 
 occur, as they may involve serious and costly changes 
 in the character of the reduction plant, or a loss of the 
 vein altogether, as at the Stonewall Jackson mine, 
 Arizona, where the native silver found in the surface 
 porph3 r ry disappeared altogether when the underlying 
 granite was reached; or, as on the Comstock lode, 
 when the fissure left the syenite-porphyry contact and 
 passed into the underlying syenite, where it presented 
 only occasional bunches of gold ore, instead of the 
 silver deposits of the eruptive contact levels. 
 
136 PROSPECTING AND VALUING MINES. 
 
 The lesson inculcated is the desirability, to say the 
 least, of a thorough examination of the line of outcrop 
 of the deposit under consideration, before erecting 
 reduction works, not only to avoid the necessity of 
 change, but to determine the probable extent of the 
 ore-bearing ground ; for if the ore be confined to a cer- 
 tain class of rocks in any particular district, the 
 extent to which such rocks are developed is an impor- 
 tant element in the future of a mining camp, and must 
 largely govern the amount of money which it will be 
 wise to invest in means of transportation, etc. 
 
 The views here set forth also explain why long belts 
 of country produce similar ores, while parallel belts at 
 no great distance often only a few miles may pro- 
 duce a totally different series over a like extent of 
 country ; or why the ores on one side of a mountain 
 range should present a totally different appearance 
 from those on the other, where both series have been 
 subjected to the action of the same eruptive rocks, or 
 to no such action on either side. It is simply because 
 they occur in parallel belts of rock of differing com- 
 position, the outcrops of which are presented to us on 
 the flanks of the mountain ranges in which they lie, 
 more or less parallel to the general summit of the 
 range or axis of elevation. Thus below the free gold 
 belt of the mother lode in California which, however, 
 is not a lode in the true sense of the word, but a belt 
 of gold-bearing rocks, in which many deposits occur 
 roughly parallel to the general strike there lies in the 
 foot hills a band of copper-bearing rocks of equal extent 
 north and south, while higher up in the range there is 
 a belt of limestone country with which are associated 
 ores of a more complex character, galena as might have 
 been expected making its appearance. 
 
 Again, just as the ancient schists of the Carolinas 
 and Georgia furnish ores of the same character, over a 
 distance of many miles, so do the ancient metamor- 
 phosed rocks of the Cascade range, in Washington, fur- 
 
INFLUENCE OF ROCKS ON VEIN FILLING. 137 
 
 nish for miles on the western slope complex ores of 
 very uniform character in each member of the rock 
 series, but differing entirely from those on the eastern 
 flank of the same range. 
 
 It is for such reasons as these that geological surveys 
 may be of very great utility, if they can be made be- 
 fore the districts have been exhausted and all the 
 thousand and one experiments and failures have been 
 tried and made; but of no direct and local value what- 
 ever if undertaken when the mining camp is wellnigh 
 deserted, although perhaps useful in showing a com- 
 parison with other localities. 
 
CHAPTER VIII. 
 MINERAL DEPOSITS OTHER THAN VEINS, 
 
 Succession of Formations. -As we have seen in dis- 
 cussing the filling of veins, it was not necessary in 
 their case that the filling should have been derived 
 from rocks which lay at a greater altitude than the 
 deposits which were being formed, although without 
 doubt a large portion of them may have been so situ- 
 ated, but in the formation of bedded deposits in strat- 
 ified rocks only a very insignificent portion are 
 derived from springs, thermal or otherwise. Deposits 
 are laid down on the top of rocks already formed and 
 covered up by others of a later date. While these 
 latter must of necessity lie conformably on the deposit, 
 or cover it horizontally, those on which the deposit 
 lies were not necessarily so. A mineral formation 
 may follow in orderly succession as one of numerous 
 layers, or it may be laid down on the upturned edges 
 of older strata, which have been tilted up and largely 
 worn away before they sank again beneath the water 
 and received a new covering. In pi. 2, fig. 1, the 
 strata E, G, D, lie conformably on each other, but un- 
 conformably on the tilted series A. If there be also 
 such a series as B we infer that it was laid down on A\ 
 that a gradual horizontal upraise brought B out of 
 the water and permitted the destruction of most of the 
 series; and that a subsequent depression, without tilt- 
 ing, allowed the deposition of E, C, D, which are also 
 said to be unconformable to B; but it is evident that 
 it will be much more difficult to trace the true rela- 
 
MINERAL DEPOSITS OTHER THAN VEINS. 139 
 
 tionship between E.C.D and B than between #and A, 
 or between E, C, D and A. 
 
 The most important deposits to us, outside of clays 
 and those which have formed building stones, are 
 those of coal and iron ore; salt, gypsum, carbonate of 
 soda, niter, and the allied minerals. The action of 
 water is evident in the formation of all these, as the 
 agent by which the material has been collected, except 
 in the case of coal, whether they have been made by 
 the ocean, to which the contained minerals have been 
 carried by streams from higher altitudes, or in inland 
 basins long since dried up, to the lower portions of 
 which other rivers have carried in solution the mate- 
 rials derived from the ridges bounding the basin, and 
 which are now in process of decay. 
 
 Solvent Capacity of Water, and Evaporation. We 
 have seen previously that heated waters have the power 
 of holding in solution a larger quantity of any given 
 material than those of lower temperatures, and that in 
 cooling they are compelled to deposit a portion of their 
 load, as in the case of hot springs, w r hich build up 
 masses of sinter around their orifices. The quantity of 
 mineral matter which such springs may bring to the 
 surface will be better understood by the statement of 
 Prof. Kamsay that the hot springs at Bath, England, 
 discharge annually sufficient solid matter to make a 
 column 140 ft. high by 9 ft. in diameter. But whether 
 hot or cold there is in any case a point at which waters 
 have absorbed and hold in suspension the maximum 
 quantity possible. This is called the saturation point, 
 and such a solution is said to be saturated. If more 
 solid matter is added to such a solution it falls to the 
 bottom undissolved, or if the amount of water be re- 
 duced by evaporation the same result follows; a por- 
 tion of the dissolved matter is squeezed out of the 
 solution as its particles contract on each other, and 
 falls to the bottom. The incrustation on boilers is 
 the result of just such a process, and the principle is 
 
140 PROSPECTING AND VAL UING MINES. 
 
 applied artificially in the production of salt from brine. 
 In nature we see it in the drying of the ground after 
 rain by the winds and sunshine, the ground losing 
 and the air absorbing the moisture; but few persons 
 realize that the loss from large reservoirs is equal to 
 36 in. annually over the entire surface; and is still 
 greater in shallow waters, where, in excessively hot 
 and dry climates, the loss by evaporation may rise to 
 as much as 1 in. in 24 hours, still going on even dur- 
 ing the night. So great indeed is this evaporation in 
 the deserts of the Great American basin that all the 
 rainfall is taken up in this manner, the numerous 
 lakes having no outlet, but varying in size from month 
 to month, and day to day, as the rainfall or sunshine 
 gains the mastery, shrinking in hot and dsy and ex- 
 panding in cool or wet weather, and always maintain- 
 ing an area which is just large enough to enable the 
 evaporating agencies to take up the exact amount of 
 water flowing into the lakes. The popular notion of 
 subterranean outlets for this water has no foundation 
 in fact, as evaporation is sufficient to account for all 
 the phenomena. 
 
 But in this process it is only the water which is lost; 
 whatever minerals or solid matter it brought down 
 from the mountains into the lakes is left there, accu- 
 mulating slowly but surely, no matter how small the 
 amount may be per gallon of water, until sooner or 
 later the saturation point is reached, and a deposit 
 begins to form of whatever salt may be least easily 
 held in solution, if there be more than one. For a 
 time the annual influx of water may be able to redis- 
 solve the precipitated portion, during the more rainy 
 part of the year, but in the course of time this precipi- 
 tate will exceed in quantity the amount soluble in the 
 annual inflowing water and a permanent deposit will 
 begin, the surface of which will suffer a partial re- 
 solution annually, but the mass itself steadily increas- 
 ing in bulk. In this inauner have gypsum, rock salt 
 
MINERAL DEPOSITS OTHER THAN VEIES. 141 
 
 and carbonate of soda been deposited from saline 
 waters; gypsum from sea water, saturated with the 
 sulphate of lime, but able to hold all its chloride of 
 sodium (common salt) in solution ; salt from similar 
 waters by evaporation, the salt in such cases contain- 
 ing the small amounts of sulphate of lime and other 
 minerals which may be in solution and which consti- 
 tute its impurities. Both of these substances are 
 therefore purely mechanical precipitates. Natural 
 evaporation has in this way produced enormous 
 masses of rock salt, like those of Cheshire, England, 
 and Cracow in Poland, both of which are extensively 
 opened by underground works; or that at Sperenberg, 
 near Berlin, which has been penetrated by an artesian 
 boring to a depth of 3,907 ft. without the bottom hav- 
 ing been discovered ; or those which are exposed on 
 the surface on the Bio Yirgen (or Virgin Biver) in 
 Nevada, which are described as follows: "A formation 
 exists at this point composed of rock salt resting on, 
 and to some extent intermixed with, sedimentary 
 rocks, and of such magnitude that it may be said to 
 constitute a notable portion of the hill in which it 
 occurs. More than 60% of this entire mass appears 
 to consist of hard rock salt, having the transparency 
 of clear ice, and containing over 90% sodium chloride. 
 This formation extends along the eastern bank of the 
 Yirgen, presenting a bluff face to the stream for a dis- 
 tance of 25 miles or more, and reaching in some places 
 a height of several hundred feet. " 
 
 These deposits are so enormous that we might even 
 be disposed to question the power of so simple a cause 
 to accomplish the results which are still, however, 
 being reached at Carmen island in the Gulf of Cali- 
 fornia and elsewhere, but the following description of 
 the Karaboghaz sea (from Sir A. Geikie) will show 
 them to be not only probable but possible: cc Along 
 the shallow pools which border this sea (the Caspian) 
 a constant deposition of salt is taking place, forming 
 
142 PROSPECTING AND VALUING MINES. 
 
 sometimes a pan or layer of rose-colored crystals on 
 the bottom, or gradually getting dry and covered with 
 drift sand. This concentration of the water is still 
 more marked in the great offshoot called the Kara- 
 boghaz, which is connected with the middle basin by 
 a channel 150 yds. wide and 5 ft. deep. Through 
 this narrow mouth there flows from the main sea a 
 constant current, which Yon Baer estimated to carry 
 daily into the Karaboghaz 350,000 tons of salt." 
 
 This amount if all deposited would cover 250 acres 
 to a depth of 1 ft. 
 
 Such deposits belong not only to the open sea, but 
 mostly to inland seas or lakes which have originally 
 formed a portion of it, and consequently partook of 
 the general diffusion of the salts which are discharged 
 into it by the rivers through its entire bulk. The 
 deposits which result from the concentration of min- 
 erals in isolated fresh water lakes will naturally par- 
 take somewhat more of the character of the salts fur- 
 nished by the rocks undergoing decomposition, and 
 which are gradually water-borne to the deepest depres- 
 sions or sink holes, there to be evaporated and con- 
 centrated or deposited. To such causes can we cer- 
 tainly attribute the lakes furnishing the carbonate 
 of soda and sulphate of soda so common in the desert 
 regions of Nevada, Utah and Wyoming, and the 
 salines producing borax, and the nitrates of potassium 
 (saltpeter) and of sodium (Chili saltpeter) in the same 
 regions and also in the deserts of South America; and 
 the bitterness of Mono lake and other waters due to 
 the presence of sulphate of magnesia (Epsom salt). 
 
 With such an origin it is plain that the efflorescence 
 or crusts of these easily soluble salts are to be sought 
 for mainly in arid regions, where the rainfall is not 
 sufficient to re-dissolve them after formation, and that 
 chiefly during the hottest portion of the year when 
 evaporation has done its work most thoroughly. The 
 presence of these salts in streams need not be per- 
 
MINERAL DEPOSITS OTHER THAN VEINS. 143 
 
 ceptible to the taste, for even good drinking waters 
 may carry an average of 20 grains of solid matter per 
 gallon in solution, but the constant accumulation of 
 even this small amount, if carried on for a time suffi- 
 ciently long, will produce all the phenomena we have 
 been describing. 
 
 Alternate Evaporated Deposits. It must not, how- 
 ever, be supposed that these deposits are always uni- 
 form in quality throughout. In many localities they 
 consist of alternating beds of salt, gypsum and clays; 
 or carbonate of soda, salt, gypsum, Chili saltpeter and 
 boracic materials with clay partings, laid down as one 
 or other of the materials predominated in the water 
 supply, owing to changes in the character of the rocks 
 from which the salts were drawn, and varying accord- 
 ing to relative solubilities. It can also easily be un- 
 derstood that they will thin out in every direction 
 round their boundaries, which are also apt to be mixed 
 with impurities blown into the lakes from the dry 
 sandy wastes, or forced in by the sudden rush of water 
 caused by cloudbursts. 
 
 Sediment Mineral Deposits. Besides the mineral 
 salts carried in solution by water, it is likely that 
 some bedded deposits owe a portion at least of their 
 contents to particles of mineral brought in suspension 
 by flowing water and deposited, like other finely 
 divided suspended matter which goes to form shales, 
 slates, etc., when the current was checked and no 
 longer able to carry them. 
 
 .Beds of Iron Ore. It is evident that in all these 
 cases there is not necessarily any chemical action tak- 
 ing place, after the water has once absorbed the 
 material to be deposited, but such is not always the 
 case in the formation of iron deposits. 
 
 While some iron ore is formed in lodes, or cavities 
 in limestone as a deposit from ferric waters (waters 
 carrying iron), probably the larger bulk of iron 
 deposits have heen thrown down in beds in the waters 
 
144 PROSPECTING AND VALUING MINES. 
 
 of swamps or lakes, through the absorptioD of oxygen 
 from plants and diatoms (infusoria) accompanied by 
 the liberation of hydrogen and carbon in the 
 shape of marsh gas. Bog iron forms in marshy 
 ground in such a manner at the present day, out of 
 waters which have become charged with iron, col- 
 lected from the sands and rocks through which they 
 have traveled ; and where the accumulations of nodules 
 and concretions have been removed, the formation of 
 others shows that the process is still in action. Such 
 deposits will naturally be most impure round their 
 margins, as in the case of coal and the minerals just 
 under consideration, and may range from mere mix- 
 tures of sand and iron, or ironstone and clay, up to 
 iron ores of great purity, according to the conditions 
 under which they were formed. True, heat and pres- 
 sure have modified many of them, eliminating the 
 water from the brown, and converting them into red 
 hematites, which by still further changes may have 
 been altered into magnetites. 
 
 Many of these deposits covered so large an area that 
 now that they have been uplifted along with the rocks 
 which contain them, and have lost a portion of one of 
 their edges by erosion, they present the appearance of 
 true contact veins, and can be worked as such ; but 
 from the difference of their origin they are likely to 
 maintain a uniform thickness for much greater lengths 
 and depths than true veins, and also to retain a more 
 uniform constitution. 
 
 Beds of Gold, Copper, Silver and Lead Ores. The 
 formation of beds of conglomerates containing gold, 
 as in South Africa, or copper as in the Lake Superior 
 region ; of sandstones containing copper as in Europe, 
 or silver as at Leeds in southern Utah, or shales con- 
 taining galena, has in nowise differed from the forma- 
 tion of similar deposits in which minerals of value 
 have not been found. It is only the presence of min- 
 eral in them which calls for attention. The native 
 
MINERAL DEPOSITS OTHER THAN VEINS. 145 
 
 copper in both conglomerates, sandstones and amyg- 
 daloidal traps (or ancient eruptive rocks) of Lake 
 Superior may have been subsequently introduced by 
 the infiltration of waters carrying copper in solution, 
 from which the copper was abstracted by the reducing 
 and transforming agency of the iron in the rocks, or 
 in other cases may have even been introduced at the 
 time the beds of sandstone, etc., were laid down, and 
 the same may be said of the grains of galena in shales, 
 but it must be confessed that the true origin of these 
 metallic or metalliferous grains is wrapped in some 
 obscurity as regards the question of time. The same 
 may be said of the chloride of silver associated with 
 the vegetable remains in the sandstones at Leeds, the 
 difficulty here being as in the other cases to account 
 for the presence of mineral in one bed of sandstone 
 and its absence from other similar formations. We 
 can only suggest that in the Leeds sandstone waters 
 carrying silver in solution were compelled by the 
 nature of the stratification to traverse the band of 
 sandstone, before its vegetable remains had become 
 petrified, and in that condition acted as reducing 
 agents on the argentiferous waters; or that the bed of 
 sandstone was formed under such circumstances, from 
 rocks containing silver, that the sediment was a com- 
 pound of both materials, which subsequently under- 
 went a chemical rearrangement through the action of 
 percolating waters, in which the organic remains 
 played the part just assigned to them, just as organic 
 matter like charcoal will precipitate gold from its 
 solution in chlorine. 
 
 The useful metals other than gold, iron, copper and 
 manganese (which is also precipitated from sea water 
 by organic remains such as bones), are, however, 
 derived to so small an extent from ancient beds that 
 their occurrence in them is more of a mineralogical 
 curiosity than an important problem for the miner, 
 who is chiefly interested in being able to distinguish 
 
146 PROSPECTING AND VALUING MINES. 
 
 between a bed and a true vein, on account of the 
 greater certainty of permanence in the former and 
 the probabilities of its position underground. 
 
 Dip of Mineral Beds As a bed belongs to a series 
 of strata which may have been uplifted, so that a por- 
 tion of them has become visible on the surface as 
 parallel outcrops, there is no certainty that the appar- 
 ent dip of the strata (that is, what can be seen at any 
 one point of exposure) will be the permanent dip of 
 the entire deposit. The probabilities are altogether 
 against such a supposition, and in favor of a flattening 
 out as the dip is followed downward toward what must 
 be the center of the basin, of which we see portions of 
 the rim only as in the case of the strata seen on the 
 left half of pi. 3, fig. 5, or the right hand halves of pi. 
 4, figs. 2 and 3. It does not, however, follow that all 
 the strata exposed will reappear when the other edge 
 of the basin is found and explored, because some of 
 them may have thinned out and disappeared in the 
 intermediate space, and their place be occupied by 
 others, or the other edge of the basin may not be seen 
 on the surface at any point, being covered up by rocks 
 belonging to later epochs. 
 
 When strata thus dip together toward each other, 
 forming a trough or basin, they are said to be "syn- 
 clinal;" when they dip away from each other, as in 
 the left hand side of pi. 4, figs. 2 and 3, or like the 
 two sloping sides of a roof, they are said to be "anti- 
 clinal;" In the former case they may rapidly pass 
 out of the limits of a surface claim and enter adjacent 
 ground, in which they may be reached by shafts. In 
 the latter case, they may pass out just as rapidly if 
 only a small portion of the top of the anticlinal fold 
 has disappeared and the location be based on an out- 
 crop of the flat top of the arch or fold; but as more of 
 the fold has been removed the dip will apparently be 
 steeper, reaching its maximum half way between the 
 top of the fold and the bottom of the adjacent trough 
 
MINERAL DEPOSITS OTHER THAN VEINS. 14? 
 
 if the folding be perfectly regular; such, however, is 
 scarcely ever the case, but the principle involved is 
 the same, as can be seen by a study of pi. 3, fig. 5. 
 
 Outcrops of Folded Mineral Beds. The peculiarities 
 of the outcrops of bedded deposits, when there has been 
 folding of the strata, are well illustrated in pi. 4, figs. 
 1, 2, 3 (after Geikie), and should be carefully studied 
 by those making locations of iron or coal deposits, as 
 they may lead to wild conclusions as to the amount of 
 ore or coal in the surface exposures. Figs. 2 and 3 
 show how, by lateral pressure, the beds laid down 
 horizontally have been squeezed until any one of them 
 presents the appearance of a piece of corrugated iron, 
 or the troughs and crests of a series of waves. By the 
 wearing away of the surface of such a folded mass the 
 edges or outcrops of the different strata would be 
 exposed as in fig. 1, of which fig. 2 is a cross section 
 on the line O H, and fig. 3 on the line C D B. B 
 forms the synclinal and A, A, the anticlinal fold of the 
 exposure, the different beds of which are numbered so 
 as to be recognizable in each of the figures. The dotted 
 lines in figs. 2 and 3 indicate the position of that por- 
 tion of the folds which has been worn away. Now, if 
 we suppose the heavy black line between 12 and 13 to 
 be a deposit of iron ore, it is morally certain that the 
 majority of prospectors would report two veins forking 
 at B y pi. 13, fig. 1, when instead of two veins, presum- 
 ably dipping into the ground to unknown depths, 
 there is merely a trough lying between the two out- 
 crops, the boundaries of which can be absolutely 
 measured and the area calculated similarly at A 4, fig. 
 1, two veins would be reported forking in a similar 
 manner, whereas it is merely the same sinuous dipping 
 away in all directions to unknown depths, and conse- 
 quently more extensive than the beds B,B, but more 
 difficult of access, and to be found below B, B if not 
 buried too deeply under the strata 5 to 12 inclusive, 
 to be reached by shafts. These remarks are intended 
 
148 PROSPECTING AND VALUING MINES. 
 
 to direct the attention of the prospector to the neces- 
 sity of ascertaining the dip of such discoveries at the 
 earliest possible moment, as a simple matter of self- 
 protection, so that he may locate the requisite adja- 
 cent ground and prevent others from gathering the 
 larger share of the fruits of his labors. Even the 
 simplest tilting of a series of strata, combined with 
 exposure of the outcrop by one stream running with 
 the dip and another across it, may present the appear- 
 ance of cross veins, particularly if some portions of 
 the outcrop are covered with debris in such a way that 
 it is not visible for its full length. 
 
 Caves, etc. Where ore is found outside of fissure 
 veins or contacts, the influence of the rock on the form 
 of the deposit is yet more strongly marked. We have 
 noted the influence which slates exert on lodes, con- 
 verting them rather into metalliferous bands of rock. 
 Limestones stamp their character upon the ore bodies 
 by the formation of chambers connected together by 
 thin seams or pipes. However irregular the series of 
 chambers may be, they must have been formed by cir- 
 culating waters (descending in the example shown by 
 the arrowheads in pi. 6, fig. 8) which followed the bed- 
 ding planes or joints, and we must consequently take 
 these as our guides when searching for the continua- 
 tion of an exhausted chamber. 
 
 In this connection it is instructive to note the great 
 similarity between a map of the workings of the lime- 
 stone contact lodes of Leadville and one of tortuous 
 chambers of the Mammoth Cave in Kentucky, carved 
 out of limestone by the action of water, the only 
 apparent difference between them being that one set 
 of chambers has been filled with ore and the other has 
 remained open. The latter fact is further of interest 
 as showing that it is possible for underground open- 
 ings of large size to exist, as opposed to the theory 
 advanced by some w ? riters that such caves are impos- 
 sible along the lines of a fissure on account of the 
 
MINERAL DEPOSITS OTHER THAN VEINS. 149 
 
 enormous pressure of the surrounding earth mass, and 
 that consequently all veins must be formed by gradual 
 substitution of one mineral for another, at the time of 
 removal. Many deposits are, however, undoubtedly 
 formed by the substitution process. 
 
 Coal and Auriferous Gravel Beds. Discussion of 
 these deposits is reserved for Chaps. XY and XVI, 
 respectively. " Masses" are noticed in Chap. IV., p. 
 81; "gash veins" and "segregations" in Chapter 
 V , p. 95. 
 
CHAPTEB IX. 
 
 PROSPECTING. 
 
 Discretion in Taking up Ground. Fortunate is the 
 man who has the instinctive ability to recognize a 
 "mine" when he sees it, and the courage to forbear 
 locating every little seam of ore he may encounter. 
 Nearly every prospector is "location poor;" loaded up 
 with so-called mines, the bulk of which should never 
 have been located; which he is confessedly unable to 
 work, and many of which were simply considered 
 "good enough to sell" when the notice of location was 
 pasted. As a general thing, nothing is worth locat- 
 ing, and it is only in exceptional cases that anything 
 is worth working, which has not a first-class surface 
 showing either in quantity or quality of ore. "Ex- 
 tensions" of good and proved mines may be excep- 
 tions. 
 
 Accurate Observation and Description. It is a com- 
 mon remark among prospectors, when the surface 
 showing is not particularly promising, that it is only 
 necessary to gain depth to make a mine. We shall 
 soon see that there is no foundation for such a state- 
 ment, when we come to consider the lesson of the out- 
 crop. But first let us look at the points which a pros- 
 pector should note about each of his locations as they 
 are made, so that he may be able to intelligently 
 explain their condition to those whose aid he may 
 desire to develop them, remembering that all ques- 
 tions which can be answered positively should be so 
 answered, and that on all other points an underesti- 
 mate is infinitely better than an overstatement. If a 
 
PROSPECTING. 151 
 
 man examining a mine for investment finds the repre- 
 sentations honestly and accurately made, the first im- 
 pression (always an important one) is favorable and 
 likely to remain ; but if first one discrepancy and then 
 another is encountered, a feeling of distrust is created 
 which may break off pending negotiations, while at 
 the same time there has been no intention on the part 
 of the owners to make a rnisstatement of facts. The 
 trouble frequently arises from the use of terms in a 
 loose way, so that they convey to the hearer a totally 
 different impression from that intended by the speaker ; 
 or it may be altogether from a want of knowledge or 
 misapprehension of the meaning of certain facts. 
 
 POINTS TO BE DETERMINED. 
 
 1. DISTANCE FOE WHICH THE VEIN on DEPOSIT CAN BE 
 TRACED. Not infrequently we are told that the vein 
 can be traced a mile, when in reality there are only a 
 series of isolated outcrops in a more or less straight 
 line, with intermediate barren or apparently barren 
 spaces, often of considerable extent. Strictly speak- 
 ing, the distance for which the outcrop can be followed 
 without a break is all that should be called traced, but 
 if the vein lie at the contact of two different kinds of 
 rock, and on following this line of junction, even 
 when no vein matter is visible, a second outcrop be 
 found on the contact, both outcrops may fairly be con- 
 sidered as on the same lode. The same will be the 
 case if the vein is formed on the wall of a dike, in 
 which case all ore bodies lying on the same side of the 
 dike may be called parts of the same vein. But as it 
 seldom if ever happens that the vein for its whole 
 length is ore-bearing, the distance the vein itself can be 
 traced is of vastly less importance (except as indicat- 
 ing its strength and probable continuance in depth) 
 than the distance the ore body, the really essential part 
 of the vein, can be followed unbroken. This length 
 should be determined even if it takes some trouble. 
 
152 PROSPECTING AND VALUING MINES 
 
 Following Dikes and Contacts. In tracing an out- 
 crop, or rather a vein, nature offers many indications. 
 If following a dike, the latter is generally much larger 
 than the vein and not infrequently harder than the 
 rocks which it traverses, standing up above them, and 
 can be taken as a guide. If the vein is on the contact 
 of two rocks, and covered in places with earth or 
 debris, it is only necessary to locate outcrops of the 
 rocks on each side of the contact, and the search may 
 safely be confined to the space between them. Nar- 
 row trenches through the surface dirt, run across the 
 general line of the lode, will easily locate the contact 
 and disclose the ore if it exists. The process is called 
 "costeaning" by the Cornish miners. 
 
 Vegetation as a Guide. Sometimes the vegetation 
 on the two different rocks, especially when decidedly 
 unlike in composition, is so different that the line of 
 contact may be traced by it alone. In open countries 
 free from heavy timber, like Arizona, this is strikingly 
 the case. Probably the most distinctive vegetation 
 in those localities is the various forms of "yucca, " of 
 which the "Spanish bayonet" is a sample; and the 
 "ocotilla" (o-ko-te-ya). The yucca is confined to the 
 granite or quartzite rocks, evidently liking a soil 
 abounding in silica (quartz); the ocotilla is as de- 
 cidedly confined to the clay-slate regions, the line of 
 contact being often drawn on a hillside by these two 
 plants as if defined by a fence; while the cactus fre- 
 quents the limestone outcrops and the areas of erup- 
 tive rocks. In other words, for successful growth, the 
 yuccas require quartz, the ocotilla clay, and the cactus 
 lime. In the broad washes or beds of summer tor- 
 rents, called "arroyos, " where the rocks are mixed, 
 all three may be found growing if the debris is of a 
 suitable character. 
 
 A fissure may also be defined by the vegetation 
 growing on it being different in character, or a line of 
 contact may be traced by the same means, as in Cali- 
 
PROSPECTING. 153 
 
 fornia, where the rim rock of the gravel channels, 
 even where covered and obscured by dense brush 
 (chaparral) can be followed along the mountain side 
 by the elderberry bushes, the white flowers of which 
 are very conspicuous in the gray brush in spring. 
 These bushes require permanent water and have 
 located themselves along the bed rock rim where 
 the water in the gravel flows over it or on the top of 
 the pipe-clay just below the lava cap. 
 
 Springs. -A lost vein may not infrequently be 
 picked up again by examining the springs along the 
 line of its general direction, as the extent of the fis- 
 sure converts it into the most available underground 
 water-course, which gives up its supply as a spring, 
 if a ravine has cut down across it, to the permanent 
 water level of the lode. 
 
 2. THICKNESS OF THE VEIN. Here again there is 
 often a confusion of the vein and the ore body. It is 
 the thickness of the latter which is the important item 
 to the intending investor; the total width of the fis- 
 sure is only of interest as suggesting a possibility that 
 at some point or other it may be completely filled with 
 ore. 
 
 How Measured. While the thickness of the ore 
 body may be accurately measured at as many points 
 as may be deemed desirable to get a fair average, the 
 width of the vein (by which is meant the distance be- 
 tween the walls at right angles to them, not horizon- 
 tally) may be very difficult to ascertain, and many 
 statements are made on this score with the best inten- 
 tions, which are misleading, because the parties have 
 no true idea as to what really constitutes the vein. 
 
 Total Width and Ore Thickness. On the Comstock 
 lode the distance between the east and west walls on 
 the surface in the Savage mine was fully 1,000 ft., of 
 which only a small part was quartz and of that only a 
 portion was available ore. The width was about the 
 same at the Chollar-Potasi mine, some 1,600 ft. to the 
 
154 PROSPECTING AND VALUING MINES. 
 
 south, with several quartz bodies cropping parallel to 
 each other, of which pi. 2, fig. 2, will give a fair idea 
 in cross section. These were at first supposed to be 
 separate veins, but at about 330 ft. below the croppings 
 the Savage mine was reduced to a width of 800 ft., 
 nearly all waste matter; and the Chollar-Potasi mine 
 to a width of 150 ft., all quartz, of which about one- 
 quarter was ore. 
 
 Veins on Dikes. In cases where the ore forms on 
 the walls of a porphyry dike (as in many of the mines 
 of the Monte Cristo district, in Washington), the 
 prospector generally calls the entire dike the vein, 
 giving it a width of from 20 to SO ft. or over, because 
 he may be able to find traces of iron pyrite in the 
 more decomposed portions of the dike, the bulk of 
 which is, however, unaltered rock. Obviously the 
 vein is only that portion of the decomposed dike 
 which has been replaced by ore. To give the entire 
 width of the dike as the vein, will create a very seri- 
 ous misunderstanding,as it is scarcely probable that it 
 will have been converted to an ore body for its full 
 thickness, at any point of its length. 
 
 False and Indistinct Walls. In other cases, where 
 there has been much motion in the fissure, its walls 
 may have become much shattered and rotten, forming a 
 series of slabs, each of which may present the smooth 
 face of a true wall, even to the slickensides, but which 
 will peel off one after the other, after a short exposure 
 to the air, making it difficult to state positively when 
 the true wall is reached 
 
 In slatey rocks there may be one wall well defined (if 
 the vein is a contact) while parallel bodies of ore or 
 barren ganglia may lie in the slates for several hun- 
 dred feet from the contact (pi. 6, fig. 1), as in the 
 mother lode of California. Under these circumstances 
 it is better to give the width of the ore, and if there is 
 a decided difference in its appearance, the width of 
 each portion, taking samples as described in Chapter 
 II. 
 
PROSPECTING, 155 
 
 If the length and width of the ore bodies as they 
 show on the surface were ascertained in this manner, a 
 large number of locations would be abandoned, having 
 failed to stand the test of working value; and while 
 the prospector would have fewer locations on his 
 hands, he would be saved the burden of the annual 
 assessment work on worthless properties, and he could 
 .honestly ask capital to aid the development of those 
 so carefully selected. 
 
 3. SAMPLES or THE COUNTRY EOCK. While a study 
 of the chapter on rocks will have enabled even a 
 beginner to speak of them with something like accu- 
 racy, it would be well to take a small hand sample of 
 the rock on each side of the vein. We have seen what 
 important differences there are in the shape of deposits 
 in different rocks, and one of the first questions an 
 expert will ask is on this subject, as it affects also the 
 cost of working most seriously, a drift or shaft in soft 
 slate costing very much less than one in hard granite. 
 Should there be a doubt as to the judgment or knowl- 
 edge of the prospector the specimens will speak for 
 themselves, and are nearly as important as the ore 
 samples. These samples need not be taken immedi- 
 ately from the walls themselves, as in such places the 
 rocks are usually greatly decayed and unrecognizable in 
 small pieces. It is better to take them a little dis- 
 tance from the vein (say from the nearest outcrop in 
 place), as these are likely to be solid, being harder 
 than their neighbors, and while taking these samples 
 to note whether the outcrop of the vein occurs in a 
 country which is badly broken up, or whether the 
 hills are large and smooth. The latter appearance 
 promises better than the former for a solid continuous 
 vein without displacements. In selecting specimens 
 the prospector should also ascertain whether the vein 
 runs parallel to the general direction of the rocks, or 
 whether it cuts across the formation features which 
 have an important influence on the probable perma- 
 
156 PROSPECTING AND VALUING MINES. 
 
 nence of the lode in depth, the latter structure almost 
 necessarily involving a deep fissure of considerable 
 length as well as depth. 
 
 The names of even the common rocks seem to be a 
 continual stumbling block to most prospectors, appar- 
 ently for no other reason than a failure to realize the 
 fact that each kind is made up of a definite combina- 
 tion of a few minerals. It would seem as though the 
 trouble of learning to distinguish from ten to twenty 
 kinds, which is about all that is necessary, ought not 
 to be such a serious matter. Every business has its 
 own language, and those who wish to excel must 
 necessarily learn to speak in a language which will 
 convey the same idea to all hearers, and each word of 
 which will convey a positive idea, instead of a hazy 
 nothing. The writer recently met a prospector who 
 had some fair-looking specimens of ore, but when 
 questioned about the mode of occurrence and the lay 
 of the country, in an effort to get an idea of the facili- 
 ties for working, in reply to a question as to whether 
 it was a granite country he answered "Yes." When 
 asked if there was slate, "yes" was the reply. And 
 to fully satisfj 7 any further inquiries which might be 
 made for other rocks he added, "There is a regular 
 jumble of them!" If this was really the case he had 
 condemned his property, as such a condition neces- 
 sarily involved a badly broken country, but it was 
 evident that he knew nothing about the subject under 
 discussion, while he simply cast a doubt upon every 
 other statement he had made, showing that he was 
 not a good observer. To make things worse he subse- 
 quently inquired what basalt was worth, and when in- 
 formed that it was merely a black volcanic rock with- 
 out value for any of the precious metals, he gently 
 intimated that his informant might know what he was 
 talking about, but that he had his own opinion on the 
 subject. His basalt proved to be orpiment, a yellow 
 compound of arsenic and sulphur. 
 
PROSPECTING. 157 
 
 4. FACILITIES FOE WORKING. The faculty of locality, 
 which must be well developed in a prospector to 
 enable him to find his waj r through the wilderness, 
 will usually also enable him to describe the best 
 routes of access to his property and what can be done 
 or has been done in the way of trails and roads. It 
 will also enable him to answer questions as to the 
 supply of timber for mining purposes (a most impor- 
 tant item) and for fuel, if coal is not accessible, so 
 that the water supply and the chances for economical 
 development are the only questions to which we need 
 allude in detail under this heading. If fuel is scarce 
 and water abundant, the latter may furnish the motive 
 power if the supply can be used under pressure, either 
 directly or through the use of electricity, and to enable 
 the prospector to readily estimate this power, a short 
 chapter has been devoted to the measurement of 
 water, and the method of calculating the horse power 
 which a given quantity will develop. This depends 
 on the quantity and the fall which can be secured, 
 modified slightly by the distance it has to be taken to 
 secure the fall, so that the prospector should be able 
 to answer these questions approximately. A measure- 
 ment of the supply taken in the dry season is most 
 desirable as giving the supply which can be depended 
 on all through the year without the use of reservoirs, 
 which are costly and often impracticable. 
 
 In not a few mining camps water is scarce during 
 the early stages of development, but while this 
 scarcity may increase the cost of the earlier work, the 
 defect is one that usually remedies itself before any 
 considerable depth has been attained, an abundant 
 supply being generally secured from the shafts and 
 tunnels, even if the quantity does not prove excessive 
 as in Tombstone, Ariz., which in early days was a 
 notoriously dry camp. 
 
 The manner in which the vein can be opened to the 
 best advantage will depend on the shape of the coun- 
 
158 PROSPECTING AND VALUING MINES. 
 
 try and the way the vein crosses it. If flat, shafts 
 must bo resorted to; if hilly, it may be better to adopt 
 tunnels if they can be run on the vein, and the pros- 
 pector should inform himself thoroughly whether this 
 can be done to advantage, which will depend on the 
 position of the outcrop. This question is more fully 
 treated in Chapter XII., on early development, and 
 attention is merely called to it here, as one of the 
 things on which all possible information should be 
 acquired. 
 
 5. LESSON OF THE OUTCROP. All the foregoing 
 remarks apply only to the surface observations, but in 
 studying the outcrop we may gain some insight into 
 the probabilities of depth. 
 
 Present Appearance not the Original The first 
 necessity is to disabuse the mind of the idea that the 
 veins were all formed after the country had assumed 
 very much its present shape and appearance. The 
 remark so commonly made, that a vein which shows 
 poorly on the surface will improve with depth, is 
 based on this fallacy, the underlying idea evidently 
 being, although probably not even thought out in the 
 mind of the speaker, that the ore at that particular spot 
 had not been able to reach the surface, a notion as- 
 sisted by the other false idea that all the filling of the 
 veins had been squeezed into them from below. 
 
 As a matter of fact there has been an immense 
 change in the surface since the majority of the min- 
 eral deposits were formed. In the case of coal fields 
 originally laid down horizontally and subsequently 
 tilted to steep angles, whole sections of these fields 
 have been worn away along with the inclosing rocks, 
 or we should have no outcrop of them. In California 
 we have absolute proof that the rocks which carry the 
 gold veins have been worn away in places, even since 
 the eruption of the basalt lavas which filled and cov- 
 ered up the old river channels to a depth of fully 
 2,000 ft., as in the canons of Slate Creek, Canon Creek 
 
PHOSPECTING. 159 
 
 and others in Sierra and Plumas counties. As these 
 old river channels carr.y gold, in fully as great a quan- 
 tity as the modern placers, which must have been 
 derived from the wear and tear of the hills which 
 formed their flanks, there must have been extensive 
 erosion before the flow of the lava, to carve out these 
 immense valleys, so that we may add an unknown 
 quantity to the known 2,000 ft., and probably be 
 within limits if we estimate the degradation of the 
 mountains carrying the gold veins at 4, 000 ft. or over. 
 Writers on Abyssinia state that in the approach to 
 Magdala gorges 4,000 ft. deep have been cut down 
 through the basalt into the underlying rocks, leaving 
 the basalt as table lands, much as in California, and 
 if gold veins traversed the rocks of the Grand Canon 
 of the Colorado we should have their secrets exposed 
 3,000 ft. below the top of the plateau, through which 
 the river has carved its stupendous gorge. It is there- 
 fore evident that in the great majority of cases the 
 outcrops of veins may be called purely accidental ex- 
 posures, which have been constantly changing in their 
 appearance for thousands of years. 
 
 Increase or Decrease in Depth. The erosion or 
 wear and tear by air and water may have proceeded 
 just far enough to uncover the top of the ore body, or 
 it may have progressed so far that nearly all of it may 
 have been removed. Are there any evidences in the 
 outcrops themselves as to which stage has been 
 reached? Before entering on this question, however, 
 let us look at the probable increase or decrease in the 
 value of the ore in depth. 
 
 In the case of veins which carry large quantities of 
 sulphuretted ores which are easily decomposed, such 
 as iron and copper pyrites, we may expect a decrease 
 in value on reaching the permanent water level of the 
 mine, below which the decomposition will not have 
 extended. If these iron pyrites carry gold, the gold 
 will have been liberated by their decomposition, and 
 
160 PROSPECTING AND VALUING MINES. 
 
 will accumulate in the cavities of the rusty quartz; 
 and as the ore after the removal of its sulphur and 
 part of the iron is lighter, bulk for bulk, than the 
 uudecomposed sulphides below, we have a greater 
 bulk to the ton and also an enriched material, so that 
 assays of the croppings are likely to be better than 
 can be had after the water level is reached. 
 
 In copper veins the decomposition of the copper 
 pyrite results in the formation of the red and black 
 oxides of copper (just as in the former case the product 
 of decomposition was oxide of iron) both of which are 
 richer in copper per ton than the sulphide; and as 
 they are practically concentrated surface deposits, not 
 extending below the water line, and may result from 
 the decay and leaching of very poor ores, we have 
 another instance in which the vein would be poorer in 
 depth. 
 
 But where no decomposition has taken place there 
 is little or no proof of continuous improvement in 
 depth, and more probability of impoverishment of the 
 vein. If the former were the case the improvement 
 ought to be continuous and there would be no limit to 
 the increase of the deposit, which we know not to be 
 the case ; and it is more than likely that the quality of 
 ore varies greatly in nearly all instances, sometimes 
 improving and sometimes growing poorer as the earth 
 is penetrated, being governed very largely by changes 
 in the character of the rocks traversed by the vein, and 
 accidental conditions which we have not yet learned 
 to realize and understand. 
 
 But the prospector need be in no doubt on this 
 point, as in most cases he can satisfy himself from 
 personal examination as to the facts. If, as has been 
 stated, the deposits were formed when the country was 
 more elevated than at present, any ravine cutting 
 across a vein or deposit explores it naturally as we do 
 artificially by sinking a shaft, and if improvement fol- 
 lows with increased depth, the outcrop at the bottom 
 
PROSPECTING. 161 
 
 of the ravine ought to be richer than one on the sum- 
 mit, as a descent of 100 ft. vertically below the top of 
 the ridge would be equal to the 100 ft. level of a shaft 
 sunk on the outcrop 200 ft. would equal the 200 ft. 
 level,and so on. How little this accords with experi- 
 ence every prospector knows. 
 
 Nothing but actual work can positively determine 
 the question whether we have merely the top or the 
 tail end of an ore body, as if we look upon the ore 
 body as a roughly shaped lens, two parallel lines 
 drawn through it, one just below the top and the 
 other just above the bottom, would each cut off. a por- 
 tion showing the same width and length; but if the 
 ore is softer than the inclosing rock, and the vein 
 crops in the bottom of a deep gorge, there is every 
 probability that the gorge has been formed by the 
 wearing down and removal of the ore body, that the 
 outcrop found, if of small dimensions, is merely the 
 lower end where the increased portion of country rock 
 resisted the action of the stream to a larger extent and 
 stopped further erosion. In a similar way, if the out- 
 crop is on a steep hillside and of only limited length, 
 it may in many cases indicate the termination of the 
 ore body, as the erosion of the ravine which has ex- 
 posed it has also disclosed some of the secrets of its 
 penetration in depth, as just described in discussing 
 the quality. But if the outcrop is of considerable 
 length and thickness, this question need not trouble 
 us, as there is sufficient justification for the expendi- 
 ture of considerable money in development. 
 
 The condition of the mineral in the outcrop may 
 also furnish a slight guide as to probable permanence 
 in depth. Some of the common minerals in ore, 
 especially the several varieties of pyrite, are easily de- 
 composed under exposure to air and water, and where 
 there is evidence in the rustiness of the outcrop, or 
 the presence of a spongy looking mass from which the 
 crystals have been perfectly removed, we may cer- 
 
162 PROSPECTING AND VALUING MINES. 
 
 tainly infer that the drainage of the vein extends to 
 some depth and involves a continuous fissure, as it is 
 only by the presence of such conditions that the de- 
 composition could have been effected. But if the 
 pyrites remain in the croppings entirely undecom- 
 posed, we may infer that the walls of the fissure are so 
 tightly in contact below as to prevent the percolation 
 or seepage of water downward, and this may be taken 
 as an unfavorable sign. 
 
 In soft and easily decomposed ore bodies the 
 removal of the outcrop running along the face of a 
 hill, instead of across it may result in shallow depres- 
 sions, instead of a conspicuous ridge, in which the 
 ore can only be found by digging; and when the ore 
 is of this character, the search for it becomes a very 
 laborious task, especially in moist and wooded coun- 
 tries, where the vegetation may be exceedingly rank 
 and tangled. 
 
 Float. From what has been said of the origin of 
 veins and the subsequent carving out of the ravines 
 and valleys as they exist to-day, it is evident that there 
 must be on the hillsides and in the ravines of a coun- 
 try rich in minerals, many fragments of mineral 
 detached from the ore bodies. These are called 
 "float," and it is equally evident that the harder the 
 material forming the gangue of the ore, the larger 
 should be the number of fragments which have escaped 
 the destructive action of air, frost, water and sun- 
 shine. Such minerals as decompose very readily, or 
 are excessively brittle, may disappear altogether, or 
 nearly so, as coal or some forms of galena; but quartz- 
 ose varieties may survive a long journey and be found 
 at considerable distances from their original source. 
 Large fragments indicate this source to be much 
 nearer than small ones. Gravity has constantly car- 
 ried these fragments to a level lower than their source, 
 so that when tracing float, as so often done, we look 
 for this source above the place at which the float has 
 
PROSPECTING. 163 
 
 been found. It may have reached this place either by 
 rolling down the hillside in the immediate neighbor- 
 hood, or it may have been carried down the bed of the 
 ravine by water. The position of the float will gen- 
 erally indicate which has been the method of trans- 
 port, but in either case we must trace it upward, and 
 if we find the fragments increasing both in number 
 and in size, we may conclude that we are nearing the 
 source of supply. Sometimes these may lead to the 
 discovery of well-defined lodes, and again, in the case 
 of quartz, we may finally lose all trace of it, without 
 encountering anything of value. This is especially 
 apt to be the case in slate countries, which have been 
 crushed and crumpled and subsequently filled with 
 innumerable thin- quartz seams. All the float may 
 have been derived from these seams, and the float 
 ceases because we have reached the limit of the slate 
 formation, and enter a new series of rocks without 
 quartz. This structure explains numbers of cases of 
 "lost leads," but while there may be no well-defined 
 vein or lode at the point where the ravine cuts the 
 formation, if metal has been found in the float it 
 shows that the region is worth prospecting and the 
 search should be continued along the line of contact 
 of the rock which has cut out the metal-bearing series. 
 Topography and Water System. The reverse is 
 just as likely to be the case where the ore body is soft, 
 as nature always carves out a country on the lines of 
 least resistance, which may be lines of faulting, or 
 contact of a soft and a hard rock, or through soft ore 
 bodies or between consolidated hard ones. For this 
 reason the study of the water system of any particular 
 mountain region affords a good insight into its phys- 
 ical structure. If all rocks were of uniform and equal 
 hardness, the face of a country would be planed down 
 to uniform smooth slopes. It is the varying resist- 
 ance of rocks which diversifies the mountain regions, 
 in combination with the dislocations they have under- 
 gone. 
 
164 PROSPECTING AND VALUING MINES. 
 
 GENERAL HINTS. 
 
 What to Look for. The importance to the prospec- 
 tor of knowing something about rocks becomes appar- 
 ent. In a granite country it is evident that he may 
 expect tin as well as a variety of other minerals, and 
 should consequently know the ores of tin (and they 
 often do not look like metallic ores) so as to be able to 
 recognize them. In a limestone belt, galena, iron and 
 zinc are specialities. In a country made up of vol- 
 canic and eruptive rocks, it is useless to look for coal; 
 but in such a country, where a belt of hot springs 
 follow the junction of eruptive rocks, especially basalt, 
 with a group of sedimentary strata, the ores of quick- 
 silver should be in his mind. In a belt of hornblende 
 rocks he may devote his energies to asbestos, soap- 
 stone and chrome iron, as well as to the precious 
 metals, and in sandstone and shale regions the out- 
 look should be kept for coal, fire clays, iron, rock salt 
 and gypsum. In a coal belt it is almost useless to 
 expect mineral veins, for apparently no fissures made 
 through a coal bed carry ore in the rocks above the 
 coal, whatever they may do below. Any one who will 
 take the trouble to put down the mineraroccurrences 
 in any extended region will soon discover that they 
 resolve themselves into a series of belts corresponding 
 with the rock formation of the country, indicating 
 most unmistakably the little understood relation be- 
 tween them. In the large basaltic areas but little of 
 interest or value need be expected, except such min- 
 erals as opal, etc. ; nor is it any use to search for the 
 soluble minerals, such as saltpeter, in any but exces- 
 sively hot regions of depression, without drainage out- 
 lets, and surrounded by volcanic or eruptive rocks. 
 
 Where to Search. Above all things the prospec- 
 tor's search should first be through all the accessible 
 regions of a mineral country, for in such districts a 
 much smaller ore body and a much lower grade of ore 
 may be more valuable financially than greater size 
 
PROSPECTING. 165 
 
 and richness in less accessible localities amid moun- 
 tain fastnesses and eternal snows. It is time to enter 
 these when all others are exhausted, though their fas- 
 cination is so extreme that it is to them that the hope- 
 ful adventurer first directs his footsteps. 
 
 Prime Requisites. What is wanted by the capi- 
 talist is a large ore body, fair average quality, good 
 working facilities and reasonably easy access. Given 
 these, there is usually no difficulty in securing all the 
 capital necessary. The want of any of these qualities 
 in the mine renders the task more difficult. 
 
 Outfit. The extent of equipment will vary accord- 
 ing to the character of the country to be traversed, 
 the distance from supply points, and whether the 
 prospector has any means of conveyance, such as a 
 pack horse or burro, or has to carry everything him- 
 self. It is unnecessary to speak here of clothing, 
 blankets, food, etc., further than to say that the lined 
 and riveted canvas suits are perhaps the most service- 
 able, and that comfortable as well as strong boots are 
 an important item. 
 
 Among the details of equipment the following may 
 be mentioned. The horn spoon is preferable to the 
 gold pan or. batea for prospecting, as being more con- 
 venient to carry (it can go in a pocket) and in use 
 requires very little water, and does not fatigue the 
 user by causing prolonged stooping. A small bottle 
 of quicksilver will be found useful when testing for 
 gold in a very fine state. A compass with folding 
 sights and a3-in. needle will help in laying off ground 
 and connecting a location with other monuments or 
 landmarks. A tape is not necessary, as one can be 
 improvised from well stretched linen cord, standard- 
 ized by some measure before starting and knotted at 1 
 ft., 1 yd., 10 yds. and 50 ft. long. If a regular tape 
 is taken that with steel wire interwoven is preferable to 
 a heavy steel tape, or a small self-winding narrow 
 steel tape can be had, which occupies less than the 
 space of a watch. A small bar magnet is useful in 
 
166 PROSPECTING- AND VALUING MINES. 
 
 cleaning up pannings. In this connection it may be 
 noted that in the absence of a regular gold pan very 
 good results can be obtained with almost any sort of a 
 receptacle, such as a frying pan, tin dish, etc. For 
 testing sulphurets and dark minerals generally a white 
 surface is preferable, such as that of a sancer or small 
 bowl, in using which when taking samples from a wet- 
 crushing battery care must be taken to avoid overflow 
 and consequent concentration if quantitative results 
 are wanted. When sampling placer ground two 
 buckets are very handy, to be used by washing from 
 one to the other. To examine ores, float, pan or horn 
 residues and rock minerals a lens is almost indispens- 
 able, and the small powerful Coddington style is per- 
 haps best. It can be hung to the watch guard. 
 
 Every prospector ought to have some knowledge of 
 the use of the blowpipe in determining ores and min- 
 erals and making rough quantitative assays. The 
 whole blowpipe kit necessary can go in the smallest 
 size cigar box. The cheap black blowpipe answers as 
 well as an expensive platinum-tipped one, and a tallow 
 candle is for most purposes better than the alcohol or 
 oil lamp. The half-dozen reagents suggest themselves. 
 A small streak plate should be included in the kit. 
 
 As to tools, the selection will depend upon means 
 of carriage and whether any real opening work is 
 intended. In prospecting in a bare, rocky counti'3 r 
 where no digging is required, a light poll pick, with 
 say a 3-lb. head or even lighter, is generally suffi- 
 cient, as this tool combines pick with hammer. 
 Regular geological hammers of peculiar shape and 
 special steel can be bought or made by any good 
 blacksmith, but are rather ornamental than necessary. 
 Of course if there are two or more in the party each 
 should take a different tool. If there is a pack 
 animal, then a light working pick and small short- 
 handled shovel will be taken. 
 
 However, as to all these matters prospectors of any 
 experience do not need to be told what is necessary, 
 
CHAPTER X. 
 MAKING LOCATIONS, 
 
 The object of making a location on a piece of min- 
 eral ground is, in the first place, to give notice to all 
 other persons that the locator has found mineral 
 therein, and has made a claim to a definite portion of 
 the deposit and a definite amount of ground to work 
 it to the best advantage. To secure this object he 
 posts on the mineral deposit a notice of his claim, to 
 be filed for record with the proper authorities at a 
 later date; and erects such monuments as will define 
 the limits of the ground claimed. This notice and 
 the monuments secure to the locator a possessory title, 
 which is good so long as the requirements of the 
 United States government, and the local laws of the 
 particular mining district in which the claim is 
 located, in regard to the amount of work to be done on 
 the claim annually and other conditions, are complied 
 with. The ultimate object of making a location is to 
 secure a patent to the ground from the United States, 
 if the property prove to be worth the expense. 
 
 What is said here applied to the public domain of 
 the United States, in the far West. In the Eastern 
 States and in foreign countries the practice is differ- 
 ent, and local regulations must be studied. 
 
 The basis of all proceedings to acquire patent to 
 mineral ground (see Chap. XI) is a duly certified copy 
 of the notice of location and the monuments which it 
 describes. 
 
168 PROSPECTING AND VALUING MINES. 
 
 Government Requirements. The instructions is- 
 sued to the deputy mineral surveyors, to whom the 
 work of making surveys for patent is intrusted, are of 
 the most stringent character. "Under these instruc- 
 tions, the surveyor has to report the true position of 
 all the original monuments, or give good reason for 
 their absence, which will be acceptable to the exami- 
 ners of the United States land office at Washington; 
 he must make the end lines of the claim parallel (if it 
 be a lode claim); and he must not include within the 
 exterior lines of the survey any ground outside the 
 corner monuments. Whether this always does justice 
 to the locator is not the question; it is the ruling of 
 the department and must be respected. Neglect to 
 restore monuments in the spring which may have been 
 destroyed by winter storms, may result in litigation 
 and endless delay in securing title, as their presence is 
 the only thing which will debar a second party from 
 coming on the ground and making an adverse loca- 
 tion. It is taken for granted that a person making a 
 location will look for monuments as a sign of previous 
 appropriation of the ground, and their absence justi- 
 fies the supposition that the ground is vacant and 
 locatable, or if previously located has been abandoned 
 by the earlier claimants. A locator cannot plead igno- 
 rance of the absence of his monuments, because as 
 they are the sole witnesses of the limits of his claim, 
 and the essential means by which he holds possession, 
 it is his duty as well as his interest to see that they 
 are maintained in good order. 
 
 Imperfect Locations. -- The number of locations 
 which satisfactorily fill the requirements that is, 
 which have all the monuments standing and so located 
 that upon survey they will not exclude some portion of 
 ground to which the claimant feels that he is honestly 
 entitled, because the location was made and held in 
 good faith is exceedingly small. The majority of 
 original locations are very imperfectly made; not from 
 
MAKING LOCATIONS. 169 
 
 lack of good intentions on the part of the locator, but 
 from want of knowledge as to what is required, or 
 how to do it, or the lack of proper instruments. As at 
 present interpreted, the instructions issued to the 
 deputy surveyors really call for nearly as great accu- 
 racy on the part of the prospector when making his 
 location as they do from the deputy when making the 
 final survey. 
 
 Theoretically the regulations are based on the idea 
 that in parting with the absolute title to the mineral 
 lands (which until a comparatively recent period were 
 regarded as the inalienable property of the crown) the 
 government is doing so on such extraordinarily low 
 and favorable terms that it has the right to demand 
 from the recipient of its bounty what it considers to 
 be nothing more than a very moderate expenditure of 
 time and money in return for its liberality. If the 
 original location has been carefully made, and the 
 monuments equally carefully maintained, the appli- 
 cant for patent will have no difficulties or delay in the 
 land office proceedings, as 90% or over of all such 
 troubles arise from defective locations or the absence 
 of monuments which the government claims should be 
 in existence. A large proportion of the remainder are 
 dela3 r ed by the imperfect character of the work on 
 which the right to patent is based. 
 
 There seems to be a popular idea that it is within 
 the scope of the authority of the deputy surveyor to 
 restore such monuments as are missing, at the distance 
 called for by the notice of location instead of in their 
 original position, and not infrequently an implied 
 feeling that he ought to do so because he had been 
 favored by selection to do the work, and most deputy 
 surveyors can testify to the difficulties which arise 
 from this source, between the applicant for survey and 
 the officers of the government, in which the deputy 
 receives no support from the government and is very 
 likely to secure the displeasure, if nothing more of 
 the applicant. 
 
170 PROSPECTING AND VALUING MINES. 
 
 WHAT CAN BE LOCATED AND IN WHAT MANNER. - 
 Knowing then what is required by the government, let 
 us proceed to make a good valid location, or rather 
 see what is necessary to make it good, first stating that 
 the extra time necessary to convert a defective loca- 
 tion into a good one is so small as to be of no conse- 
 quence when compared with the subsequent saving of 
 time, money, and annoyance; remembering that if the 
 ground is worth locating at all it is worth while to 
 make the location absolutely secure. 
 
 Mineral Must be Found. No valid location can be 
 made until mineral has been found within the limits 
 of the claim in the condition required by the charac- 
 ter of the location made. 
 
 Placer locations may be made on ground in which 
 valuable minerals, such as gold, tin, platinum, iridos- 
 mine, etc., are mixed with sand, gravel, clay or bowl- 
 ders, the minerals having been removed by natural 
 causes from their original position in the rock in 
 place. Placer ground on unsurveyed land may be 
 taken in any shape which the locator desires, provided 
 the ground contains mineral as described, and pro- 
 vided the area does not exceed 20 acres to each locator 
 or 160 acres to an incorporation. But if the land has 
 been surveyed by the government, the claims must be 
 made to conform to the smallest legal subdivisions 
 (which in this case is 10 acres), the limits of the placer 
 ground being first determined, and then so adjusted 
 on the margins of the location that 10-acre tracts hav- 
 ing less than five acres of placer ground are excluded, 
 and those having more than five acres of available 
 ground are included. When the final survey for 
 patent is made on unsurveyed land, it will be made to 
 conform to the original takes or monuments, no matter 
 how irregular the shape of the track may be, regard- 
 less of anything except area, and this, if in excess, 
 must be cut down to the limit allowed by law. When 
 the ordinary land surveys are extended over such 
 
MAKING LOCATIONS. 171 
 
 areas the section lines are adjusted to such surveys, 
 just as in the case of lode claims. 
 
 Lode Locations. In the location of mineral veins 
 or lodes, whether they be of gold, silver, copper, lead, 
 iron, tin, quicksilver or -other minerals found in lodes, 
 the United States laws grant to each locator the right 
 to take in one location not more than 1,500 ft. in 
 length on the lode, and not more than 300 ft. on each 
 side of the center of the lode. A location cannot be 
 made with 200 ft. on one side and 400 ft. on the other. 
 There is nothing compelling the locator to mats his 
 location 600 ft. wide, the law simply says he may so 
 make it. 
 
 Local Regulations. Within these limits the width 
 is optional with the locator, and by the action of a 
 duly organized meeting of the miners in any district, 
 may be limited to any quantity not less than 25 ft. on 
 each side of the center of the lode, making a total 
 width of only 50, instead of 600 ft. In Bodie, Cal., 
 for instance, the width was fixed at 100 ft. on each 
 side of the center line. 
 
 The local laws of a mining district may impose any 
 other conditions which the miners may see fit, pro- 
 vided they do not grant better terms than are offered 
 by the government. These may be just as much more 
 stringent as the miners may think desirable for the 
 welfare of the district, as, for instance, while the United 
 States laws have been construed to grant the locator 
 one year from the first day of January succeeding the 
 date of his location in which to do the $100 worth of 
 work by which he holds his title, the district laws may 
 decide that work shall be commenced inside of 60 or 
 any other number of days, or stipulate for other evi- 
 dences of good faith on the part of the locator; but 
 they cannot legally declare, as is sometimes attempted 
 to be done, that a shaft 10 ft. deep, which only cost 
 $50, shall be considered full value for the required 
 annual expenditure of $100. Such a proposition is 
 
172 PROSPECTING AND VALUING MINES. 
 
 always open to contest. As the want of roads often 
 greatly retards the opening of otherwise promising 
 mining camps, a clause might very suitably be added 
 to many local laws, stipulating that each location pay 
 annually a definite sum to some authorized agent to 
 accumulate as a road fund, in addition to the $100 
 work required by the government, but such payment 
 could not be made to constitute a portion of the 
 annual assessment work. 
 
 Mineral "in Place." As previously stated, no loca- 
 tion can be made which will be of any value until 
 mineral has actually been found, and for a lode loca- 
 tion it must be in the undisturbed rock, or "rc-^k in 
 place." Monuments or no monuments, any outsider 
 can prospect over such a lode location, and if h** suc- 
 ceeds in finding mineral in place before the earlier 
 claimant, he can make an adverse location ana will 
 surely hold the ground. In Leadville, for instance, 
 where the ore did not crop on the surface (u r ing 
 nearly horizontally), the ground was covered with 
 overlapping locations, but the shaft which first got 
 down to and struck the deposit took the ground as 
 against the other claimants. 
 
 Agricultural and Timber Eights. No mining loca- 
 tion, either lode or placer, or for iron or for coa-, can 
 be made on any ground for which a patent has been 
 issued, unless it can be conclusively proved thffc the 
 party obtaining such patent was aware of the existence 
 of mineral on his claim at the time of " proving up" 
 and falsely swore to the contrary. This applies to 
 patents to agricultural and timber lands. A lode claim 
 can be filed over a placer claim, as lodes are expressly 
 exempted from placer patents, but across such placer 
 claim, the lode camp has surface ground only 25 ft. on 
 each side of the center of the lode. 
 
 Locations can be made on all other classes of land, 
 provided mineral has been found thereon ; but when 
 made on land valuable for timber or agricultural pur- 
 
MA KING LOG A TIONS. 173 
 
 poses, are liable to contests before the land office to 
 determine whether the ground is more valuable for 
 mineral or for other purposes. 
 
 Monuments. A monument should be conspicuous 
 enough to be readily found. According to the char- 
 acter of the region, it may be either a tree with the 
 side blazed; a small sapling cut off about 4 ft. from 
 the ground with the top squared ; a simple stake about 
 4 ft. long squared at the top, and driven not less than 
 12 in. in the ground, if there are no rocks convenient; 
 or such a stake with a rock mound at its base; or even 
 a simple pile of rocks where there are no trees. 
 
 Tree or Stake Marks. In all cases where a tree or 
 stake is used a sufficient space should be smoothed on 
 which to write the designation of the corner intended 
 to be represented. If a tree is used, it is not suffi- 
 cient to simply bark it, because trees in falling often 
 skin the bark off each other in patches, and such a 
 "blaze" is easily overlooked; but the blaze should be 
 made as in pi. 15, figs. 1 and 2, with a straight notch 
 at the bottom, cut well into the wood and dressed 
 smooth to wrrte on with a soft pencil. Fig. 1 shows 
 the front view of a proper blaze and fig. 2 the side ap- 
 pearance. Such a mark is unmistakable and immedi- 
 ately suggests the prior presence of men, which the 
 other method does not. 
 
 Stone and stake monuments are easily overturned 
 and destroyed, especially in snowy altitudes and on 
 steep hillsides, but there would not be half as much 
 trouble in keeping them in good shape if a little more 
 care were exercised in building them. They are 
 usually a heap of rocks, instead of a monument. It 
 takes no more rocks to build a good than a bad one, 
 and but little if any more time all depends on the 
 manner of placing the stones. If the monument is to 
 contain a stake, this should be driven solid, with a 
 rock for a hammer if necessary, and the ground 
 roughly leveled off with the pick, which the prospector 
 
174 PROSPECTING AND VALUING MINES, 
 
 always carries, so as to get a good foundation. This 
 is all important on a hillside. The necessary supply 
 of rocks should then be got together, before starting 
 the structure. The biggest and flattest should be laid 
 in a circle round the stake, at a little distance from it, 
 in such a way that their upper surfaces slope inward 
 toward the stake. By taking this precaution with the 
 bottom layer, the next layer will have a tendency to 
 slide in toward the stake, thus making it almost im- 
 possible for the monument to tumble down, while the 
 stake will be wedged tightly in place by the pressure ; 
 and if this principle is applied until the monument is 
 completed, say three courses, with the inner space 
 filled up solid with small rocks and dirt, there need be 
 no fear of its destruction, except willfully or by snow- 
 slides sweeping everything before them. If the latter 
 are feared it is best not to have the central post too 
 high, as it will then offer less resistance to the over- 
 turning action of the snow. PI. 15, figs. 3 and 4, 
 show a properly and an improperlj r built monument in 
 cross section. In the latter there is every chance for 
 the monument to fall apart and release the stake from 
 its position. Every stone in a monument should be 
 moved about until it has a perfectly solid bearing, and 
 does not wobble. 
 
 Simple Eock Monuments. In building a monument 
 of rocks alone, the importance of a good foundation is 
 even greater, for the absence of the central stake in- 
 creases the liability to destruction. A moderately 
 large base tapering somewhat rapidly will give the 
 greatest stability. 
 
 Inspection of Monuments. To emphasize the im- 
 portance of building well, it will not be out of place 
 to repeat that the owner of an unpatented claim should 
 at least annually examine the corner monuments, and 
 see that they are standing, for as they are often the 
 only means by which a stranger can have knowledge 
 of the existence of a location or its extent, and their 
 
MAKING LOCATIONS. 175 
 
 object, is to give notice to the world of an existing 
 claim, their absence gives the stranger a perfect right 
 to locate the ground as vacant lands of the United 
 States. 
 
 Notices of Location. These should accurately de- 
 scribe the monuments as actually set. Prospectors 
 frequently take out a set of printed blanks in which a 
 "mound of stones" is usually called for, and then 
 simply fill in the blank spaces with the number of feet 
 located, when it often happens that no mound of stones 
 was made, but a tree blazed, or a small sapling cut 
 off, in places where there is a scarcity of rocks suita- 
 ble for a monument. Frequently the stake called for 
 does not exist, and the writer has seen cases where the 
 monument, so called, was nothing more than a small 
 piece of a broken limb stuck in the ground, without 
 any notice of what it was intended to represent, and 
 absolutely not recognizable as a monument, and this 
 in the midst of dense timber. Such negligence is 
 inexcusable, and if trouble arises the locator has no 
 one but himself to blame. It is, of course, allowable 
 to use one of these printed blanks to make and post 
 the original notice at the point of discovery, to hold 
 the claim while the discoverer may be putting up his 
 end and corner monuments, but the final notice, of 
 which a copy is filed for record, should call for a 
 blazed tree, describing its markings, if such were 
 used, a sapling squared, a post without mound, a post 
 with rock mound, or a rock mound only, as the case 
 may be. t Occasionally the notice of location calls for 
 a monument of some kind, in a position which is inac- 
 cessible, and where none was actually set, so that 
 when the deputy surveyor comes along and reports 
 that he cannot reach the point called for, there imme- 
 diately arises a question of veracity between the loca- 
 tor and the deputy, which may seriously delay the 
 proceedings in the land office. If the point where the 
 monument should be set is inaccessible, the location 
 
176 PROSPECTING AND VALUING MINES. 
 
 notice should say so, and give the reason for not set- 
 ting the corner, and if set as a witness post to show 
 the direction of the end line, the supposed distance to 
 the corner should be written thereon. The absence of 
 a post at any of the corners, if such cannot be set, 
 does not invalidate a location, if the fact be so stated, 
 as the law does not ask impossibilities, but the state- 
 ment that a corner was set in an inaccessible place, 
 when it was not so set, is sure to result in trouble. 
 
 Posting Notices. In addition to fully describing 
 the monuments in the notice of location, they should 
 be so marked as to indicate what position they occupy 
 with reference to the claim, as "north end center of 
 Deadwood lode," "northwest corner of Dead wood 
 lode" etc. ; but if a stone monument be used the 
 notice may be folded up and placed between two flat 
 stones or in a tin can, with the mouth downward to 
 keep it dry. Such a tin can is also very useful even 
 when a post is used, as it can be tacked to the same 
 (pi. 15, fig. 5) in a similar manner and forms a very 
 noticeable and conspicuous object. If there are trees 
 near the monuments, they should also be blazed and 
 marked as witness trees. 
 
 The notice should distinctly state the name of the 
 state, county and mining district in which it is made, 
 the name of the miner, the name of the adjacent 
 claims if they are known, the date of discovery, the 
 date of location, with witnesses if possible, and refer- 
 ence should be made to prominent natural objects, so 
 as to make the position of the claim ascertainable, if, 
 after all precautions have been taken, the monuments 
 should be accidentally destroyed, as by floods or 
 snowslides. Such references may be, for instance, 
 "on south side of Index Mountain," "on the north 
 side of Crab Creek, 2 miles above its junction with 
 Pole Creek," "2 miles northeast of Minersville," etc. 
 
 The exact wording of the notice of location is of but 
 little consequence, so long as it gives the information 
 
MAKING LOCATIONS. 177 
 
 previously stated, as a location of lode claim neces- 
 sarily carries with it all the dips, spurs and angles, 
 and all the privileges granted by the various acts of 
 Congress, without a recital of such claims. All that is 
 required is such a document that no one can misun- 
 derstand the intention of the locator. If this is 
 clearly done, the shorter the notice the better. 
 
 It has taken some time to describe the requisites of 
 a first-class notice of location, whereas it only takes a 
 few minutes to write it out and secure the satisfaction 
 which always goes with a job well done, but it is not 
 intended to imply that a notice not so complete as 
 here sketched would be invalid. But very few con- 
 tain every item in detail, yet the nearer it approaches 
 to the correct thing the more safely can the prospector 
 leave his claim to the tender mercies of the elements. 
 
 How TO MAKE A LOCATION. Placer and Coal. In 
 making a location of placer or coal ground on surveyed 
 land the location notice should describe the ground 
 by the usual legal subdivisions, and this will consti- 
 tute a valid description because it can be immediately 
 filed in the United States land office and become the 
 best public notice obtainable; but if the placer claim 
 is on unsurveyed land, a monument must be set at 
 every change in the direction of the exterior bound- 
 aries and mentioned in the location notice. Coal 
 lands can only be taken in legal subdivisions as platted 
 on the ordinary land surveys, and cannot be pur- 
 chased before survey of the township has been made. 
 
 Lodes. In the case of lode claims it is customary 
 to set the ends of the lode line and the four corners of 
 the claim, but there have been decisions by the gen- 
 eral land office in which, with only the end center 
 stakes established, the locations were sustained. If 
 this method be employed the discovery stake, as well 
 as the monuments at the ends of the claim, should be 
 most thoroughly established, and all of them should 
 plainly show that the locator claims a definitely speci- 
 
178 PROSPECTING AND VALUING MINES. 
 
 fied distance on each side of his lode line. Such de- 
 cisions are based on the theory that the surface 
 ground is granted only to enable the miner to work 
 his claim to the best advantage, and on the further 
 idea that a person finding a lode will naturally follow 
 the outcrop in the course of his examination, and 
 must consequently find any monuments already 
 erected on the vein, thus gaining knowledge of the 
 claims of any prior locators. But this would not 
 occur if the locator were following a lode parallel to 
 one previously located and say, therefrom, so that it is 
 very much safer to establish all the corner monuments, 
 this method having the additional advantage of defin- 
 ing the direction of the end lines, which is left open 
 to interpretation in the other case, unless it is plainly 
 stated that they are to be at right angles to the lode 
 line. The following remarks will therefore apply only 
 to claims having all corners established, except where 
 they are evidently applicable to other locations also. 
 
 It may seem a very simple matter to make a lode 
 location after finding ore just measure off 1,500 ft. 
 and set the corner posts but there are many points 
 to be considered, if we want to secure the full privi- 
 leges granted by the mining laws. Should there be 
 any mistake in the form or direction of the original 
 location, and adjacent claims be taken either endwise 
 or laterally before the mistake is discovered, it will be 
 too late to remedy the defect by a new location; as, 
 for instance; if the direction of the lode line as 
 located does not follow the lode, which may be found 
 to run diagonally across the location, and pass out of 
 the side instead of the end lines. In such a case the 
 side lines become the end lines, making the. location on 
 the lode much shorter than if the lode ran lengthwise 
 of the claim. To avoid such errors, which may ruin 
 an otherwise valuable mine, time enough should be 
 taken to ascertain the true direction of the vein before 
 measuring off the location, After establishing the 
 
MAKING LOCATIONS. 1?9 
 
 initial monument or discovery stake on the ore body, 
 and posting a notice of location thereon, so that there 
 can be no doubt as to what vein is intended to be 
 located, the prospector is entitled to a reasonable time 
 in which to perfect his location. 
 
 Very often the notice of location is posted at one 
 end of the claim (see A 9 pi. 15, fig. 10) and calls for 
 " 1,500 ft. on this vein, beginning at the post on 
 which this notice is posted," or similar language, 
 when there is no vein in sight at that particular point, 
 leaving the intention of the locator uncertain, or to be 
 interpreted only by finding the monument at the other 
 end of the location, and ascertaining what outcrop 
 may fall on a line drawn between the two monuments, 
 which may or may not be the vein intended. As in 
 pi. 15, fig. 11, if the notice be posted at either end of 
 the lode line 1 or 2, a line connecting these points 
 may show the outcrop of ore to be say 150 ft. from the 
 line, in which case, in strict compliance with the law, 
 in final survey for patent, the line from 5 to 6 should 
 be run through the point 7, making the distance from 
 7 to the center of the outcrop not more than 300 ft. 
 By establishing a discovery monument all doubt is 
 ended. 
 
 Lode Line and Outcrop. It is not absolutely neces- 
 sary that the location should be made in a straight 
 line, but the lode line should follow the outcrop with 
 reasonable accuracy. This is often a very crooked 
 line if the vein has a flat dip. If the vein is largely 
 quartz and therefore generally harder than the sur- 
 rounding country rock, it will probably crop boldly 
 and can be traced without difficulty. If softer than 
 the inclosing rocks, it may only crop on the steep 
 sides of ravines, and be covered on the gentler slopes 
 by earth and debris, in which case it may be necessary 
 to dig a few cross trenches at short intervals apart, so 
 as to disclose its course. (See Chap. IX., for method 
 of tracing outcrop.) "When all other signs fail it will 
 
180 PROSPECTING AND VAL UIN9 MINES. 
 
 probably be found to run parallel to the general direc- 
 tion of other veins in the district, or else nearly at 
 right angles thereto. Jn the latter case it may prove 
 to be only a spur of a larger vein, as shown on pi. 3, 
 fig. 4, E. At any rate a notice at the point of discov- 
 ery will hold a claim for a few days, while the true 
 position of the end lines is being established, and with 
 ordinary diligence and a little woodcraft the direction 
 of the lode may generally be determined with a rea- 
 sonable amount of accuracy, if the principles govern- 
 ing the outcrop of a vein have been mastered, and the 
 vein is strong enough to be worth locating. 
 
 In cases where the vein does not crop distinctly for 
 1,500 ft., it will be good policy to make two locations, 
 establishing one of the end lines of each location 
 through the discovery stake on the outcrop as in p). 
 15, fig. 9, which leaves a portion of the cropping on 
 each location, A and B. This plan has the advantage 
 also of lessening the chance of the rake of the ore body 
 in depth carrying it beyond the end lines of the claim, 
 and offers a better chance to develop both locations 
 through the same tunnel or shaft. This plan is much 
 preferable to the common one (pi. 15, fig. 10) of cov- 
 ering all the outcrop by the location A and making 
 extension locations B and C, in which no outcrop is 
 visible, as the latter locations are invalid until ore has 
 been found in them. In the one case the locator has 
 a good title to 3,000 ft. in the other to only 1,500. 
 
 Length and Extensions. Having determined the 
 direction of the lode line, and the manner in which he 
 will make his locations, the locator can measure out 
 any number of feet in either direction for his claim or 
 claims, provided the total length of each one does not 
 exceed the statutory limit of 1,500 ft., and the end 
 monuments may be established. From the same point 
 he can take one claim with say 500ft. in one direction 
 and 1,000 ft. in the other, or two claims of 1,500 ft. 
 each, one in each direction from the discovery. If 
 
MAKING LOCATIONS. 181 
 
 only one claim is laid off, it is good policy to be sure 
 that the location is fully 1,500 ft. long; if a little 
 more it will not matter, as on final survey the claim 
 can be cut down to its proper length if in excess, but 
 it cannot be lengthened beyond the original stakes, if 
 they have been established too close together, and the 
 claimant may lose a portion of ground to which he 
 might have been legally entitled. If on the other 
 hand, a series of locations are made on the same vein, 
 it will always be policy to make the locations a trifle 
 less than 1,500 ft. each in length (unless measured 
 with the accuracy of a final survey), so as to avoid 
 awkward gaps between them, as will be seen must 
 occur in such a series as shown in pi. 15, fig. 6, where 
 it is evident that the end lines of location A must be 
 finally established at 1 and 2. If 2 has been taken as 
 one end of B, the other must be set 20 ft. short of the 
 original post at 3, or at 4. The ends of D can be set 
 at 5 and 6, but if 5 be taken as one end of G there will 
 be a gap of 60 ft. between 3 and 7, making a total of 
 80 ft. at this point to be relocated, and secured only 
 by an expenditure of $500 for labor, in addition to the 
 cost of survey and land office proceedings. Under 
 other circumstances the gap of 20 ft. may occur near 
 2 and 60 ft. near 5. It is better to make the locations 
 safe from this defect by making each of them a trifle 
 short and making an additional one, if necessary to 
 cover all the ground desired. 
 
 Even in the case of four claims of rather irregular 
 length, but aggregating just 6,000 ft., all owned by 
 the same corporation, the laud office would not permit 
 the adjustment cff the dividing end lines to make four 
 even surveys of 1,500 ft. each, but requires strict 
 adherence to the original monuments. 
 
 Setting Corner Monuments. -In setting the corner 
 monuments, be sure that they are> if anything, a little 
 farther from the lode line than the distance called for 
 in the notice of location, as the distance allowed on 
 
182 PROSPECTING AND VALUING 
 
 final survey cannot be greater than the position of the 
 corner monuments calls for; in other words, the 
 monuments govern and not the words of the location 
 notice. No ground can be included in the final sur- 
 vey for patent which lies outside straight lines con- 
 necting the monuments as they exist on the ground^ 
 and the end lines must be parallel. 
 
 Having taken the precaution to keep the corner 
 monuments far enough away from the lode line so that 
 the finally established side lines shall fall within 
 them, it is next necessary to see that they are so 
 located that the end lines can be drawn parallel to 
 each other, and yet pass through the end monuments 
 on the lode line. It is here that the deputy surveyor 
 usually encounters the greatest difficult}'. The situa- 
 tion can best be explained by such a diagram as pi. 
 15, fig. 7, in which Z shows a defective location, be- 
 cause if AB represents the lode line, and CJ),E,F, the 
 four corner monuments; the surveyor, to make the end 
 lines parallel, must prolong EB m toward F as in the 
 dotted line, and then from C lay off a parallel line 
 toward D thus cutting the lode line short by the dis- 
 tance A H. He cannot draw the end line SS through 
 A, because it would include ground outside the posts 
 or monuments, namely the triangles S,D,A and S,C,A 
 not included in the original location. In the same 
 figure W shows a well-made location, so far as the 
 prospector's interests are concerned, as it is evident 
 that the end lines SS and 00 can be drawn through 
 the lode line posts A and J", without shortening the 
 length of the lode line, and can have a variety of di- 
 rections given to them, while remaining parallel, a 
 point of great importance, as will be seen shortly. 
 
 It follows almost inevitably that one satisfactory loca- 
 tion must in common practice necessitate an adjacent 
 location in bad shape, so that whatever may be said of 
 the policy of making the lode line monuments of one 
 location common to its extensions, the ordinary prac- 
 
MAKING LOCATIONS. 183 
 
 tice of making the corner monuments also common to 
 adjacent claims should be abandoned by those who 
 wish to avoid trouble on final survey. Independent 
 posts should be established as shown on pi. 15, fig. 8. 
 In this figure the corner monuments of location A are 
 marked a 3 a*a 5 a 6 , while its corners of location B are 
 numbered 6 3 ,6*,fr 5 , and 6 6 . The diagram explains 
 itself, being only two locations like W in fig. 7, placed 
 end to end. By adopting this system, the parallel end 
 lines can be located anywhere in the ground covered 
 by the overlapping corners, as shown by the heavy 
 parallel cross lines. 
 
 End Lines. The acts of Congress grant to the 
 locator 1,500 linear feet on the vein, and call for par- 
 allel end lines, so that a uniform length on the vein 
 shall be maintained at all depths, as the miners follow 
 the vein downward on its dip, the end lines being ex- 
 tended downward vertically and prolonged indefinitely 
 in the direction of the dip. If any other policy were 
 allowed, the ownership on the vein in depth would 
 be a variable quantity, diminishing in length if the 
 end lines of the claim converged toward each other in 
 the direction of the dip, and increasing if they 
 diverged from each other, as can bo seen by reference 
 to pi. 15, fig. 12, which shows tw r o locations on the lode 
 a b, the dip being indicated by the arrow. The 
 dotted lines show the non-parallel end lines prolonged 
 in the direction of the dip, and it is plain that the 
 location G would constantly be gaining, while D 
 would be losing ground in depth. For this reason 
 the end lines of a claim must be kept parallel in justice 
 to both locators. It is not, however, always an eas.y 
 matter to do this, the first locator usually getting in 
 practice an advantage over his later located neighbor. 
 
 Surface Length and Actual Lode Length. While the 
 grant says "1,500 ft. on the vein"it is in reality 1,500 
 ft. on the line of the outcrop of the vein measured 
 horizontally, and by varying the angle between the 
 
184 PROSPECTING AND VALUING MINES. 
 
 end lines and the lode line, the locator may acquire 
 either less than 1,500 ft. measured horizontally on the 
 real vein or a great deal more. Take for instance the 
 case presented in pi. 14, fig. 1, in which AB shows a 
 location of 1,500 ft. on the outcrop of the vein AC, a 
 tunnel on the vein starting on the outcrop at A and 
 terminating at C, on the prolongation of the end line 
 of the location DE, which is made at right angles to 
 the lode line. The dip of the vein in the direction of 
 the arrow is 60 from the horizontal, and the rise 
 of the mountain side on which the outcrop is located 
 from A to B is 500 ft. Fig. 2 shows a cross section 
 of the lode on the line CDE in fig. 1, and the dimen- 
 sions just given make the horizontal distance from 
 BB, which is vertically under the point B on the out- 
 crop on the end line, to the tunnel at C 287 ft. (ignor- 
 ing fractions). Returning to fig. 1, the line AC, or 
 the actual distance owned by the locator on the lode 
 horizontal^, will therefore be longer than the length 
 on the outcrop; viz., the square root of 1,500 squared 
 plus 287 squared, or 1,527 ft. approximately. 
 
 If the rise of the outcrop is 33, as is not infre- 
 quent, the height of B above BBom C will be 817 ft. 
 and the distance BC 408.5 ft. ; and AC will be 
 1,546.7 ft. 
 
 But if the dip of the vein be 45 and the slope of 
 the outcrop is 33, B will be 817 ft. above C; BC will 
 be 817 ft. long, and AC 1,708.2 ft., or 208.2 ft. longer 
 than the grant on the outcrop. 
 
 Hence it can readily be seen that the apparently un- 
 important question of the position of the end lines in 
 really one of great importance to the owner, when the 
 lode has a flat dip and crops on steep hillsides, cut- 
 ting a smaller and smaller figure as the country be- 
 comes flatter or the lode more vertical. "When per- 
 fectly vertical both lines would be the same length; as 
 also in a level plain. (PI. 14, fig. 1, is distorted to 
 give better room for display.) 
 
MAKING LOCATIONS. 185 
 
 When making a single location on a vein, rect- 
 angular end lines may be undoubtedly the best; but 
 the reverse may be true where a series of such loca- 
 tions are made, unless the outcrop of the vein follows 
 a verj' straight line, which is only the case when it is 
 nearly vertical. If sinuous or crooked, as in pi. 14, 
 fig. 3, where a,aa"a" is the outcrop and the arrow 
 shows the dip, a single location like ^will be satis- 
 factory; but if we add another, as W, at a later date, 
 ^will take everything in depth between the dotted 
 lines ab and ab, while W will only be able to follow 
 the vein downward till it encounters the line a'b, and 
 stops the shaded triangle between the lines a'b and 
 a"c. If a third location X be made as shown, no one 
 will own the gore between the lines a'c and a"e, nor 
 can title be acquired thereto, because there is no 
 vacant ground on the outcrop at a" on which to base a 
 location. This is, of course, an extreme case, but if 
 all the locations are made in the interest of the same 
 parties, it is evidently better that the end lines should 
 be made as in pi. 14, fig. 4, because the distance on a 
 horizontal line between the end lines ab and hh would 
 always remain the same, at any depth; whereas in fig. 
 3 the end lines ab and a'"h converge, and would ulti- 
 mately intersect each other and cut out the ownership 
 of the lode completely. 
 
 Puzzling Locations. It may be well to call atten- 
 tion to some other defective forms which result from a 
 vein with a dip, traversing a hilly country cut up with 
 deep ravines, producing the results discussed in the 
 subject of outcrops and illustrated in pi. 9, figs. 3 and 
 5, and from the frequent want of a continuous out- 
 crop. If the ore chutes are as shown in pi. 9, fig. 7, 
 the outcrops would be conspicuous on one side of the 
 ravines as at cc, but would be scarcely visible on the 
 other, as at dd. In a plan these outcrops would be seen 
 as at aa in pi. 14, tig. 5, which shows two ravines with 
 intervening hills. For want of knowledge how to 
 
186 PROSPECTING AND VALUING MINES. 
 
 trace a vein, a great number of locations are made by 
 continuing the line of the visible outcrop as in the 
 locations ZZ in a straight line, but if the dotted lines 
 show the connecting portion of the vein, not exposed, 
 it is evident that it will pass out of the side lines of 
 the locations at bb. The complications which could 
 arise from such a condition of things, on working the 
 lodes, are almost endless, varying according; to the 
 priority of location and the direction of the dip of the 
 vein. 
 
 Another form of trouble arising from the same 
 causes is shown in pi. 14, fig. 6, in which aa are the 
 outcrops of the same vein, on two sides of a ravine, 
 the connection between the two not being visible on 
 account of accumulated debris in the stream bottom. 
 Instead of two locations crossing each other, a single 
 location should have been made following the solid 
 lines, but modifying the direction of the end lines as 
 shown. Such a location, while having 1,500 ft. on 
 the outcrop, would have a shorter length on the vein, 
 but whatever this might be, it would remain uniform. 
 
 In granite countries, especially, the ore bodies may 
 be short, lying in the vein somewhat as shown in pi. 
 
 6, fig. 5, where the peculiarity is exaggerated for 
 illustration, and may present themselves as a series of 
 short, more or less parallel outcrops, as in pi. 14, fig. 
 
 7, aaa. These are often made the basis of a series of 
 locations as XXX, when the true line of the vein is 
 shown by the dotted line, and two locations, as ZZ, 
 might have covered the property at a saving of several 
 hundred dollars. 
 
CHAPTEE XL 
 PATENTS TO MINING GROUND. 
 
 IN the States and Territories where the United 
 States mining law is operative the acquisition of title 
 in fee simple to mineral land is somewhat more com- 
 plicated than to agricultural lands, as special surveys 
 must be made in most cases to separate it from the 
 latter, except in the case of coal and stone lands, which 
 are sold by subdivisions of the ordinary land surveys; 
 or in the case of placer ground where the government 
 surveys have already been extended over the placer 
 area, in which latter case the land can only be taken 
 iii the usual legal subdivisions, except that the selec- 
 tion can be made in as small quantities as 10-acre 
 tracts. But in all cases of application for patent to 
 mineral land a full description by exterior boundaries, 
 or by legal subdivisions, must be published, so as to 
 allow an opportunity for agricultural claimants or 
 others to contest the application, if so inclined. 
 
 Except where special surveys have to be made to 
 segregate the mineral land from the surrounding 
 agricultural area, the proceedings originate in the 
 "United States land office for the district in which the 
 land may be situated ; but where surveys have to be 
 made they originate in the office of the United States 
 surveyor-general for the State in which the locations 
 lies. Thus the United States surveyor-general deals 
 only with those claims which require special surveys; 
 and to these w ? e will first give attention, as they 
 include the much larger proportion of mineral loca- 
 tions. 
 
188 PROSPECTING AND VALUING MINES. 
 
 Before going further it will be well to note the dif- 
 ference between a "location" and a "claim," as the 
 words are often used indiscriminately, although in land 
 office proceedings they have distinct and very differ- 
 ent meanings. A lode location must not exceed 1,500 
 ft. in length by 600 ft. in width; and a placer loca- 
 tion must not contain more than 20 acres, but may be 
 of any shape necessary to cover the ground sought to 
 be purchased. On the other hand a claim may include 
 as many locations as the owner or claimant may have 
 been able to purchase, provided they are adjacent to 
 each other, and a patent for a single claim may con- 
 tain many locations. In such a consolidated survey 
 and patent the aggregate of say eight placer locations 
 must not exceed 160 acres, and no one of the individ- 
 ual locations must exceed 20 acres; if any of the loca- 
 tions fall short of 20 acres, the loss cannot be made 
 good by allowing an excess in some other location. 
 
 Procedure on all Lode Locations, and such Placer 
 Locations as Lie on Unsurveyed Land.' In these 
 matters a uniform process must be gone through 
 and a rigid adherence to the routine of the surveyor- 
 general's office, as well as that of the local land office, 
 will greatly facilitate progress. 
 
 Duties of the Surveyor. All mineral surveys in- 
 tended to form the basis of an application for a United 
 States patent must be made by a deputy mineral sur- 
 veyor. These deputies are appointed by the United 
 States surveyor-general for the State, and are placed 
 under bonds for $10,000, with two sureties, qualifying 
 in double the amount, for the faithful performance of 
 their duties, which are carefully defined in the gov- 
 ernment instructions, and from which there can be no 
 diviation without the risk of serious trouble both to 
 the surveyor and the applicant. 
 
 Deputy Surveyor's Fees. The deputy is paid for 
 his services by the applicant, who has the right to 
 select whomever he may prefer, and the compensation 
 
PATENTS TO MINING GROUND. 189 
 
 for the work is a matter of agreement between the 
 applicant and the deputy, as there is no recognized 
 scale of fees; such an arrangement being impossible 
 on account of the widely different conditions under 
 which the surveys are made as to accessibility of the 
 locality, roughness of the ground and number of sur- 
 veys to be made in any one locality. It is evident that 
 the incidental traveling expenses will be just as great 
 for the survey of one location as for ten, if they are 
 in the same vicinity. 
 
 The following extracts from the instructions issued 
 to the deputy mineral surveyors by the surveyor- 
 general for the State of "Washington will show 
 the limit of their authority and furnish a guide to 
 applicants for survey in preparing their case : 
 
 Field Work (7). The survey made and reported must, in every case, be an 
 actual survey of the ground in full detail, made by you in person after the 
 receipt of the order, and without reference to any knowledge you may have 
 previously acquired by reason of having made the location, survey or other- 
 wise, and must show the actual facts existing at the time. If the season of 
 the year, or any other cause, render such personal examination impossible, 
 you will postpone the survey, and under no circumstances rely upon the 
 statements or surveys of other parties, or upon a former examination by 
 yourself. 
 
 The term " survey " in these instructions applies not only to the usual field 
 work, but also to the examinations required in the preparation of your affi- 
 davits of $500 expenditure, descriptive reports on placer claims, and all other 
 reports. 
 
 (4) No return by you will be recognized as official unless made in pursuance 
 of a special order from this office. 
 
 Not to Act as Attorney (6). You are precluded from acting either directly 
 or indirectly as attorney in mineral claims. Your duty in any particular 
 case ceases when you have executed the survey and returned the field notes 
 and preliminary plat with your report to the surveyor-general. You will 
 not be allowed to prepare for the mining claimant the papers in support of his 
 application for patent, or otherwise perform the duties of an attorney before 
 the land office in connection with a mineral claim. You are not permitted to 
 combine the duties of surveyor and notary public in the same case by ad- 
 ministering oaths to parties in interest. In short, you must have absolutely 
 nothing to do with the case except in your official capacity as surveyor. 
 You will make no survey of a mineral claim in which you hold an interest. 
 
 Survey and Location (8). The survey must be made in strict conformity 
 with, or be embraced within, the lines of the recorded location upon which 
 the order is based. If the surrey and location are identical, that fact must 
 be clearly and distinctly stated in your field notes. If not identical, a bear- 
 ing and distance must be given from each established corner of the survey to 
 the corresponding corner of the location. The lines of the location as found 
 upon the ground, must be laid down upon the preliminary plat in such a 
 manner as to contrast and show their relation to the lines of the survey. 
 
 (11) In accordance with the principle that courses and distances must give 
 way when in conflict with fixed objects and monuments, you will not, under 
 any circumstances, change the corners of the location for the purpose of 
 
190 PROSPECTING AND VALUING MINES. 
 
 making them conform to the description in the record. If the difference 
 from the location be slight, it may be explained in the field notes, out if there 
 should be a wide discrepancy, you will report the facts to this office and 
 await further instructions. 
 
 From the foregoing it will be seen how important it 
 is that everything should be in good order on the 
 ground before the surveyor is sent on to it. There is 
 a widely prevalent idea that the surveyor can rectify 
 any irregularities which he may discover, and reestab- 
 lish corners which may be missing, without any prob- 
 ability of future trouble, but this is not the case. It 
 is true he can take testimony to ascertain the former 
 position of missing corners, but this involves delay and 
 extra expense for which, in the very large majority of 
 cases, the applicants are unwilling to pay; and as the 
 entire theory of the mining laws is based on the sup- 
 position that a party places no value on a neglected 
 article the applicant should not be surprised if the 
 authorities who have to pass on the legality of his loca- 
 tion take that view, and make no excuses for things 
 which ought to have been, and might have been, in 
 better shape. 
 
 The duty of the surveyor is simply to report the 
 facts as he finds them on the ground; if a stake or 
 monument is missing he must so state, giving such 
 reasons as may apparently account for its absence, at 
 the same time leaving the examining authorities to 
 judge whether such reasons are satisfactory; if the 
 monument is in existence he must so report, and if 
 not identical with the corner of a survey he must ex- 
 plain why it is not; he cannot increase the length of a 
 claim if it has been made less than 1,500 ft. originally ; 
 and he must make the end lines parallel, though the 
 side lines need not necessarily be so. In fact he is 
 not allowed to be in any sense a judge of the equities 
 of the case; he is simply employed to collect the in- 
 formation by which others can adjust them. 
 
 Duties of the Applicant. The following extract is 
 from the official instructions; 
 
PATENTS TO MINING GROUND. 191 
 
 (4) ... You are therefore advised, before filing your application, to sec 
 that your location has been made in compliance with law and regulations, 
 and that it properly describes the claim for which patent is sought. 
 
 Office Charges. There are certain charges for work 
 in the office of the surveyor-general which are indepen- 
 dent of the contract with the surveyor, and are 
 intended to cover the cost of examining the filed notes 
 of the survey and the preparation in quadruplicate of 
 the maps and field-notes, one copy of which is sent to 
 Washington to the general land office, two to the ap- 
 plicant, and the other is retained on file in the office 
 of the local surveyor-general.- 
 
 (5) With regard to the platting of the claim and other office work in the 
 surveyor-general's office, that officer will make an estimate of the cost 
 thereof, which amount the claimant will deposit with any assistant United 
 States treasurer, or designated depository, in favor of the United States 
 treasurer, to be passed to the credit of the fund created by individual depos- 
 tors for surveys of the public lands, and file with the surveyor-general the 
 duplicate certificate of such deposit in the usual manner. 
 
 (6) The following is the estimated cost of platting and other office work in 
 connection with the survey of mineral claims :* 
 
 Lode claim $35 00 
 
 Placer claim 35 00 
 
 Mill site claim 35 00 
 
 Mill site included in one survey with a lode claim 25 00 
 
 Each lode claim inc uded in the survey of a placer claim 25 00 
 
 Several lode or placer claims in one survey, each location , 35 00 
 
 Descriptive report on placer claim taken by legal subdivisions 10 00 
 
 (7) Should the office work, in any case, amount to more than the above 
 estimate, an additional deposit will be required. 
 
 (8) In districts where there is no United States depository, you should de- 
 
 Eosit with the nearest assistant United States treasurer, or depository, and 
 i all cases immediately forward the original certificate (of deposit) to the 
 secretary of the treasury (at Washington, D. C.) and the duplicate to the 
 surveyor-general, retaining the triplicate for your own use and security. 
 Under no circumstances will the deposit be made w th the surveyor -general. 
 The deposits for office work are not to be made until the applications for 
 survey are received, and the parties notified by the survey or- general. 
 
 The order of procedure is therefore as follows: 
 1. Application Blanks. As applications for survey 
 must be made on the blank forms adopted by the sur- 
 veyor-general's office, the applicant, unless he can 
 secure one from the deputy surveyor, should write to 
 the surveyor-general for a blank form. 
 
 Particulars. This application contains the name of 
 the deputy who has been selected to make the survey, 
 
 *This is the scale issued by the State of Washington, and is only given tc 
 convey a general idea of the cost. 
 
192 PROSPECTING AND VALUING MINES. 
 
 and a request for an estimate of the office fees. It 
 should also be filled out with the name of the claimant 
 in full, as it is desired to appear in the application to 
 the land office for patent; the name of the mining 
 claim in full, stating whether it is a lode or placer 
 claim ; the name of the mining district, and the land 
 office district in which the claim is located, and if the 
 claim is made up of several locations, they should all 
 be enumerated in detail. 
 
 With this application, there must be forwarded <f a 
 copy of the record of location of the claim, properly 
 certified by the recorder having charge of the records 
 of the mining locations in the county where the claim 
 is situated/' This may be either the recorder of the 
 mining district, if one has been regularly organized, 
 or the county recorder if no district has been formed, 
 or the organization has been abandoned or fallen into 
 disuse. When securing this certified copy of the 
 notice of location, a second one should be secured and 
 delivered to the deputy who is to make the survey, as 
 he has to make the survey in conformity with the 
 notice and return it to the surveyor-general as a por- 
 tion of his field-notes. The deputy has also to file 
 with his returns a copy of the laws of the mining dis- 
 trict, if such be organized, and it is important that 
 the location should conform to these laws and regula- 
 tions. A local miners' organization may impose any 
 conditions they see fit on a locator, provided they do 
 not conflict with the general mining laws of the United 
 States, and as long as such local rules are in force in 
 a district, any application which takes an amount in 
 excess of the local regulations is liable to be returned 
 for correction. 
 
 2. Deposit; Receipt; Order for Survey. When ap- 
 plication for survey has been filed with the ^surveyor- 
 general, he will notify the applicant of the cost of the 
 office work, and this sum must be deposited as previ- 
 ously explained. On the receipt of the duplicate 
 
PATENTS TO MINING GROUND. 193 
 
 receipt, showing that the charges have been deposited 
 to his credit, the surveyor-general issues his order of 
 survey to the deputy mineral surveyor, who can make 
 no official move until he is in receipt of this authoriz- 
 ation. The applicant has nothing further to do until 
 the survey is completed, and has been examined and 
 platted by the proper authorities. 
 
 As the surveyor has to make with his returns a 
 statement of the value of the work done on the loca- 
 tion, supported by the affidavit of two disinterested 
 persons, the applicants should be careful that fully 
 $500 has been expended in actual mining improve- 
 ments, as if this has not been done, the papers are 
 likely to be returned, involving loss of time and ex- 
 pense. The common notion that $5 should be allowed 
 for each day's work on the location is erroneous; 
 labor should be counted at its current rate, whatever 
 it may be, and to estimate a man's labor at $5 per 
 diem for the purpose of securing patent to the ground 
 and only at $2 per diem for other purposes suggests a 
 fraudulent intent, and may lead to trouble, as it is not 
 carrying out either the letter or the spirit of the law. 
 It is evident that if the location is worth patenting at 
 all, it is worth honest returns as to the value of the 
 improvement, by which is meant the actual amount of 
 money spent upon the ground, in which estimate 
 traveling expenses and such other items are not 
 allowed. 
 
 3. Publication. When the returns of the surveyor 
 have been examined and approved by the surveyor- 
 general, he forwards to the applicant two copies of the 
 field-notes and two copies of the official plat. The 
 applicant must then make an agreement with the 
 nearest local newspaper for the publication of the notice 
 of intention to apply for a patent, which notice must 
 contain such a description of the ground, made up from 
 the field-notes sent by the surveyor-general, as will 
 fully identify the ground and give notice to all adjacent 
 
194 PliOSPymXNQ AND VALUING MINES. 
 
 owners and others of what ground is claimed. This 
 notice must be published 60 days, or if in a weekly 
 paper it must appear in nine consecutive issues. When 
 this publication is decided on, the applicant must post 
 one copy of the map and field-notes upon the claim.. 
 in some conspicuous place, in the presence of two 
 witnesses, who must be disinterested parties, and 
 this notice must remain on the ground during the 
 entire period of publication. 
 
 During this period of publication, any one has the 
 right to file an adverse claim to the ground, but if 
 such claim is not filed during this period the adverse 
 claimant is debarred from further proceedings. Such 
 adverse claim when filed must be accompanied with a 
 plat of the ground showing the conflict of interest, for 
 the information of the prior claimant, and suit must 
 be commenced within 30 clays in the proper court, to 
 determine the respective rights of the parties, and 
 such suit must be prosecuted with diligence to a termi- 
 nation. Evident negligence to do this justifies the 
 land office in taking steps to force it, or dismiss the 
 adverse claim. 
 
 Documents to be Filed; Final Proof. If there be 
 no adverse claim filed, the applicant is then ready to 
 proceed with his final proof before the United States 
 land office for the district in which the claim is situ- 
 ated, and will be required to file the following papers 
 in the case : 
 
 1. Application for patent, on the usual blank forms, which must be in the 
 name of the party or parties, or incorporation, making the application for 
 survey. 
 
 2. The copy of the surveyor-general's official plat, with the accompanying 
 field notes. 
 
 8. A complete abstract of title, properly certified by the proper authori- 
 ties. 
 
 4. Affidavit of citizenship, or in the case of an incorporated company, of 
 such incorporation, as no patent can issue to an alien. 
 
 5. Affidavit by two disinterested parties of the posting on the ground of the 
 notice to apply for a patent, giving date of posting and locality at which it 
 was posted. 
 
 6. Affidavit by two disinterested parties that such documents remained 
 continuously posted during the entire period of the publication of the notice 
 to apply for patent in the newspaper. 
 
 7. Agreement with the publisher as to cost. 
 
PATENTS TO MINING GROUND, 195 
 
 8. A copy of the notice of publication, cut from the paper. 
 
 9. Affidavit of the publisher that such notice was published the requisite 
 number of times, giving the dates, name of paper, and place of publication. 
 
 30. Certificate of the clerk of the Superior Court that there is no suit pend- 
 ing affecting the ownership of a title to the ground. 
 
 11. Affidavit of two disinterested parties as to the value of the work done 
 and its character. (These must be actual mining improvements. Houses, 
 roads and trails are not considered necessarily mining works, unless they are 
 connected with tunnels, shafts, or other mining excavations). 
 
 12. Affidavit by the applicant of the costs which have been incurred in 
 securing the patent, including such items as monies paid the surveyor, pub- 
 lisher, attorney, etc. (The object of this is twofold : (1) To protect the ap- 
 plicant against exorbitant charges; and (2) to protect the government by 
 disclosing whether prices have been paid which might be inferred to have 
 influenced the judgment of the person receiving them. 
 
 13. Application to purchase. 
 
 Payment need not be made on the day on which the 
 "final proof " is made in the land office, by the pres- 
 entation and approval of all the papers in the case, 
 but good policy involves prompt attention to this, as 
 the payment of the money due the government is ac- 
 knowledged by the issuance of a "duplicate receipt" 
 which stands in the place of a patent, and answers 
 every purpose of such a document, until the patent is 
 issued, which is a matter of routine in Washington 
 and may not be reached for a year. 
 
 Government Land Prices. The price for lode loca- 
 tions and mill sites is $5 per acre; for placer ground 
 $2.50 per acre; and for coal lands $20 per acre. 
 
 Contests. The foregoing proceedings in the land 
 office are practically applicable to all mineral lands, 
 and apply to all simple uncontested cases. The United 
 States land office is also the referee where there may be 
 a difference of opinion as to the character of the land, 
 as between mineral and agricultural claimants, the 
 contestants presenting their individual views by testi- 
 mony, but all questions of ownership are decided by 
 the courts. These may include priority of location, 
 overlapping of locations, intersecting or cross veins 
 and so many other contingencies that in all cases of 
 conflict the services of an attorney must be called in. 
 This chapter is intended only as a guide in those cases 
 where all is plain sailing. In all others a good special 
 land lawyer should be consulted. 
 
196 PROSPECTING AND VALUING MINES. 
 
 Further Instructions. The following extracts from 
 the circulars issued for the guidance of deputy sur- 
 veyors may be of interest: 
 
 13. The order of approval of surveys of mineral claims is prescribed by 
 general land office circular, dated March 3, 1881, as follows: 
 
 " The mining survey first applied for shall have priority of action in all its 
 stages in the office of the surveyor-general, including the delivery thereof, 
 over any other survey of the same ground or any portion thereof. 11 
 
 "When the survey first authorized is not returned within a reasonable 
 period, and the applicant for a conflicting survey makes affidavit that he be- 
 lieves (stating the reasons for his belief), that such first applicant has aban- 
 doned his purpose of having a survey made, or is deferring it for vexatious 
 purposes, to wit, to postpone the subsequent applicant, the surveyor-general 
 shall give notice of such charges to such first applicant, and call upon him 
 for an explanation under oath of the delay. He shall also require the deputy 
 mineral surveyor to make a full statement in writing, explanatory of the 
 delay; and if the surveyor-general shall conclude that good and sufficient 
 reasons for such delay do not exist, he shall authorize the applicant for the 
 conflicting survey to proceed with the same; otherwise, the order of proceed- 
 ing shall not be changed. 11 
 
 " Whenever an applicant for a survey shall have reason to suppose that a 
 conflicting claimant will also apply for a survey for patent, he may give a 
 notice in writing to the surveyor-general, particularly describing such claim, 
 and file a copy of the notice of location of such conflicting claim. In such 
 case the surveyor-general will not order or authorize any survey of such 
 conflicting claim until the survey first applied for has been examined, com- 
 pleted, approved and platted, and the plats delivered. 11 
 
 13. Your attention is directed to the first . . paragraphs of general land 
 office circular dated December 4, 1884, viz : 
 
 "1. The rights granted to locators under section 2322, Revised Statutes, 
 are restricted to such locations on veins, lodes or ledgos as may be * situated 
 on the public domain.' 1 In applications for lode claims where the survey 
 conflicts with a prior valid lode claim or entry, and the ground in conflict is 
 excluded, the applicant not only has no right to the excluded ground, but he 
 has no right to that portion of any vein or lode the top or apex of which lies 
 within such excluded ground, unless his location was prior to May 10, 1872. 
 His right to the lode claimed terminates where the lode, in its onward course 
 or strike intersects the exterior boundary of such excluded ground and 
 passes within it. 11 
 
 "2. The end-line of his survey should not, therefore, be established beyond 
 such intersection, unless it should be necessary so to do for the purpose of 
 including ground held and claimed under a location which was made upon 
 public land and valid at the time it was made. To include such ground 
 (which may possibly include other lodes) the end-line of the survey may be 
 established within the conflicting survey, but the line must be so run as not 
 to extend any further into the conflicting survey than may be necessary to 
 make such end-line parallel to the other end-line." 
 
CHAPTER XIL 
 
 EARLY DEVELOPMENT OF MINES. 
 
 WHEN satisfied from thorough examination of the 
 surface indications that a deposit of mineral is worthy 
 of further exploration, the question arises as to what 
 the character of these explorations shall be, to accom- 
 plish the best results in the shortest time and at the 
 least expense. 
 
 "Follow the Ore." There is one rule from which 
 there should be no variation, whatever plan may be 
 adopted, in all preliminary works, and that is, to fol- 
 low the ore wherever it may go, no matter how crooked 
 the shape of the developments may be; as it is only 
 by determining the shape and character of the deposit 
 that later works can be laid out intelligently and eco- 
 nomically. This plan has also the advantage of to 
 some extent paying for the work of development; as, 
 if the ore is rich enough to ship, it will furnish a cer- 
 tain amount of cash to continue the work, while at the 
 same time such shipments will attract the attention of 
 mining men, and go far toward effecting a sale if this 
 is contemplated, or securing aid to prosecute the work 
 on a larger scale. Even if the ore be too poor to ship, 
 the dump may yet be a valuable asset, and the number 
 of tons it contains will be evidence of the faith of the 
 owners in their property, and will furnish a better evi- 
 de'nce of the producing capacity of the property than 
 any series of mere measurements. 
 
 Cross-cut Tunnels. How often this rule is disre- 
 garded may be seen by the frequent newspaper notices 
 
198 PROSPECTING AND VALUING MINES, 
 
 that ''so-and-so have started a tunnel to tap the vein 
 200 ft. deep/' or some other attractive figure, when in 
 all probability the deepest hole on the property may 
 not be 10 ft. deep. Such schemes are usually based 
 on the mistaken idea so often heard repeated, that the 
 mine will "show up" in depth. Deep cross-cut tun- 
 nels are admissible for working purposes when the 
 mine is proved to be worth the cost of driving them, 
 but thev are unadvisable at the beginning of opera- 
 tions, unless it is impossible to approach the ore body 
 in any other way; and in such cases the surface show- 
 ing must be more than ordinarily good to justify such 
 a procedure. Such early works have two fatal defects : 
 (1) A shaft must be sunk ultimately, connecting the 
 surface and tunnel to give ventilation, and good policy 
 would indicate the propriety of sinking the shaft first, 
 and running the tunnel afterward to meet it, if the 
 showing in the shaft justified it; and (2) such a cross- 
 cut tunnel through the rocks which inclose the vein 
 may cut the vein where it is barren or in a " pinch," 
 and cause the abandonment of the property ; and at the 
 best, after months of work, it tells us the character of 
 the ore and the thickness of the vein or deposit at the 
 single point where it is encountered, when we ought 
 to be learning something daily for every dollar ex- 
 pended. The point where the vein is cut may be 
 much poorer than the ore on either side at compar- 
 atively short distances away, causing an underestimate 
 of the value of the property; or the ore encountered 
 may be a rich bunch, giving exaggerated ideas of value ; 
 or the ore may have thinned out and disappeared alto- 
 gether, which fact would have been demonstrated 
 much earlier in a shaft. Such a tunnel, unless fol- 
 lowed up by explorations of the vein laterally, adds 
 little to the value of a property which may be offered 
 for sale, because it does not prove continuous ore from 
 the surface to the depth at which it cuts the lode it 
 only renders it probable; while the same money spent 
 
EARL Y DEVELOPMENT OF MINES. 199 
 
 in sinking on the vein might have produced a market- 
 able proposition, or proved the smallness of the ore 
 body at much less cost. A tunnel to tap ihe vein, 200 
 ft. deep, is not likely to be less than 300 ft. long, and 
 when completed and without drifts, only exposes an 
 area of the vein some 5 by 7 ft. in extent, while a 
 shaft 80 ft. deep, and 220 ft. of drifts and cross-cuts 
 (300 ft. of work in all) would demand the attention of 
 anybody looking through a mining camp with a view 
 to purchase. Sinking even small shafts or inclines is 
 of course rather more expensive than tunneling, es- 
 pecially if the mine is at all wet; on the other hand, 
 it is quite possible that the ore followed down and 
 taken out as sinking progresses may make up the dif- 
 ference. 
 
 Depth of Tunnel Connections. Many erroneous esti- 
 mates are made of the depth at which a tunnel of a 
 given length will tap a vein, unless actual survey 
 has been made instrumentally, the tendency being 
 almost always to overestimate the depth. The best 
 guide is to note the condition of the surface. Long 
 rock slides and mining dumps usually stand at angles 
 varying from 30 to 35, which figures give respec- 
 tively a rise or fall of from 58 to 67 ft., or an average 
 of about 63 ft. in 100. To get 200 ft. of depth in a 
 distance of 200 ft., the angle will be 45, a very steep 
 climb, and this occurs only in very precipitous 
 regions. 
 
 Tunnels in Foot or Hanging Wall. Disappoint- 
 ment also results from running the tunnel in the foot 
 wall of the vein, because in addition to the distance 
 necessary to reach a vertical shaft sunk on the out- 
 crop, if such existed, there must be added the addi- 
 tional distance caused by the lode dipping away from 
 the mouth of the tunnel, which is often forgotten. 
 Such tunnels, if they must be run in early develop- 
 ment, should be run if possible in the hanging wall, 
 so as to take advantage of the vein approaching the 
 tunnel on its dip in depth. 
 
200 PROSPECTING AND VALUING MINES. 
 
 Drift Tunnels. Two other methods of early develop- 
 ment are possible one by sinking on the vein, the 
 other by tunneling, or rather drifting on it, starting 
 on the outcrop and following in on the lode. This 
 last method is by far the most satisfactory, as ifc proves 
 both length and depth, for if the ore is continuous in 
 the tunnel and in the outcrop overhead, we are justi- 
 fied in considering that it is continuous to the depth 
 of the tunnel, and below, if it shows in the floor of the 
 drift, and the mine has then what is known as "re- 
 serves," or ore proved and merely waiting extraction. 
 This method of development also possesses the advan- 
 tage (which may often be an inducement to run the 
 cross-cut tunnels just discussed) of one man being 
 able to work alone, using alternately the pick or 
 single-hand drill and wheelbarrow; and upraises 
 can be made from time to time to the surface with 
 ease, as the material mined falls of its own weight to 
 the floor of the drift, and can be removed without ad- 
 ditional labor. If timbering is to be done two men 
 are almost essential, and it may not be advisable 
 under any circumstances to work alone in a tunnel in 
 loose ground, on account of the risk of accidents, but 
 it can be done in an emergency. 
 
 Sinking on the Deposit. There are, however, many 
 cases where we cannot at once drift on the lode, as the 
 desirable localities maybe covered by heavy debris, 
 and the exact location of the vein unascertainable, and 
 we must then resort to sinking on the deposit. Here 
 again we must follow the ore, whether it makes the 
 shaft vertical or converts it into an incline. At first 
 one man at the windlass will do, and two men can 
 manage for a depth of 80 to 100 ft. When this depth 
 is attained it may be profitable to drift on the lode 
 toward daylight, through the accumulated surface 
 debris, and having reached daylight, to continue 
 operations by drifting on the vein ; or if it is desired 
 to sink deeper, a horse whim will be able to hoist 
 from a depth of 200 ft.^ or somewhat more. 
 
EARL Y DE VELOPMENT OF MINKS. 201 
 
 In sinking by hand regard should be had to the size 
 of the barrel or spindle of the windlass on which the 
 rope is wound, as it requires less power to raise a 
 heavy bucket slowly than rapidly. The size of the 
 spindle should therefore be smaller (say Gin.) for deep 
 work than for shallow pits, not only because a small 
 spindle raises the bucket a shorter distance at each 
 revolution of the crank and so relieves the strain, but 
 because its diameter is rapidly increased by the wind- 
 ing of the rope upon it, making the strain greater and 
 greater as the load approaches the top. 
 
 Water. The appearance of water in a shaft may, 
 however, modify all the conditions, and compel a 
 resort to cross-cut tunnels, but- if present in large 
 quantities, and artificial drainage is possible, its pres- 
 ence may be considered a favorable indication, as it is 
 evidence that the fissure on which work is being pros- 
 ecuted is extensive and drains a large area, and may 
 consequently contain larger bodies. Such a condition 
 is certainly more promising than a dry hole in which 
 the ore shows little sign of decomposition, or of the 
 former circulation of water. 
 
 Position of Main Working Shafts. Usually, from 
 the nature of the explorations and the surrounding 
 physical conditions, especially where the mine must 
 be worked on a large scale by deep shafts, the loca- 
 tion of such. shafts in suitable relationship to the lode 
 is a matter of much importance. When the dip of the 
 vein or deposit is comparatively flat we may be com- 
 pelled to adopt an inclined in preference to a vertical 
 shaft, unless it be so flat that it can be worked like a 
 coal mine, on an almost horizontal floor. But when 
 the vein stands nearly vertical the greater facilities for 
 operating a vertical shaft may make such a plan desir- 
 able. We must then remember that all mining ex- 
 penses increase with depth, and if dead work has to 
 be done to reach the ore in the lode it is better to do 
 ji'uch work near the surface, while expenses are, IQYY or 
 
202 PROSPECTING AND VALUING M1NEK. 
 
 moderate, than at greater depths where they are high 
 and constantly increasing. PL 9, fig. 2, illustrates 
 this, showing a vein and two shafts A and B, in cross 
 section across the lode. B is evidently better located 
 for economical working than A, because in the latter 
 the length of the crosscuts from the shaft steadily in- 
 creases with depth, while in B the longest crosscuts 
 are near the surface, and, for the depth shown, the 
 total amount of dead work is much smaller than in A 9 
 with increasing advantage for greater depth. 
 
 The same principle is illustrated in pi. 9, fig. 4, as 
 regards the position of the shaft lengthwise of the 
 vein, C being the ore shoot, with a decided rake to 
 the left. (The rake usually diminishes with the in- 
 crease of dip, being least in vertical lodes; and is usu- 
 ally similar in all the veins of a district having the same 
 general stri'ke and dip.) Here B located near the 
 center of the outcrop, would not be in as good a posi- 
 tion as A, for the reasons just given. 
 
 Cross- Cutting : In all explorations on the vein un- 
 derground, the importance of intelligent cross-cutting 
 is obvious. No ore bodies are fitted into a clean-cut 
 fissure with mathematical accuracy. The crushing of 
 the rocks which make the formation of a mineral vein 
 possible also had a tendency to scatter the ore bodies 
 when formed, and because one body of ore gives out 
 in a drift it by no means follows that all- the ore has 
 given out in the mine. It may simply be shifted 
 laterally to another plane of the "sheeting. " The 
 Keystone mine, Amador County, Cal., is cross-cut to 
 a width of several hundred feet with profit; and it does 
 not even do to assume a perfectly smooth, continuous 
 rock face to be either the foot or hanging wall, as a 
 case in Colorado shows, where such a wall was followed 
 by a drift for several hundred feet, and when broken 
 into under a change of management, proved to be only 
 one side of a more valuable body of ore than had been 
 extracted by the drift. 
 
EARLY DEVELOPMENT OF MINKS. 203 
 
 Usually the distance to which the cross-cut may be 
 carried is indicated by the condition of the rock 
 through which it is driven. As long as this shows 
 evident signs of decay or change, or traces of mineral, 
 so long it may be desirable to continue the cross-cut; 
 but it should be stopped as soon as the rock assumes 
 the character of the main body of the wall rock visible 
 on the surface, and not in contact with the vein. If 
 working in limestone where the ore occurs in pockets 
 and chambers the little stringers of ore should receive 
 especial attention. 
 
 System in Development. In all these operations the 
 watch word should be utility and economy. Unintel- 
 ligent management may easily swamp an enterprise 
 which in proper hands would have proved a success. 
 Every bit of w<ork done on a location should be the 
 result of a carefully planned scheme, the portions of 
 which will fit together when completed. Especially 
 should this be the case with the annual assessment 
 work. Too often the owner looks upon this work as a 
 burden, and desires to do just as small an amount of 
 it as will legally hold the claim until he can sell it. 
 Such skimped work will seldom sell a claim. Few 
 realize that only by putting work on a mining loca- 
 tion can it> in most instances, be made a salable or 
 valuable proposition; and in a large proportion of 
 cases, for want of judgment, the work done leaves the 
 property looking worse than if nothing had been done 
 upon it. 
 
 Prospect Pits.- If only small sums of money are to 
 be spent annually, these will be best expended in 
 tracing the ore body by a series of shallow pits, 
 rather than by starting short tunnels one after the 
 other in places where work is easy, only to leave 
 them in barren ground. As at present expended, 
 most of the money spent on assessment work is prac- 
 tically thrown away, for want of system. 
 
 Large surface excavations, except such as are neces- 
 
204 PROSPECTING AND VALUING MINES. 
 
 sary to trace the ore, are not desirable, in wet or 
 snowy countries especially, as they only serve to divert 
 the rain and snow into the mine, from which it may 
 later on have to be pumped at heavy cost. 
 
 Common Terms Used in Mining.* Definitions of a few 
 of these may be in place here: A "shaft" is a vertical 
 opening, either on or alongside of the vein if that is 
 vertical, or outside of it (preferably in the hanging 
 country) if the lode has a dip, but intersecting it in 
 depth. An "incline" is a sloping shaft, usually made 
 to follow the vein or ore bed. It may not be so con- 
 venient as a vertical shaft for working, but involves 
 less dead work in opening a mine. A "winze" in a 
 shaft connecting the interior workings, but not com- 
 ing to daylight. It may be either vertical or an 
 inclined winze. A "chute" (shoot) is a winze suitably 
 lined to pass ore and waste from the workings to the 
 cars on a lower level. ("Chute" is also applied to 
 a pitching ore body.) The drain tunnel, or lowest 
 horizontal opening by which water can be discharged 
 from the mine, is the "adit." "Drifts" or "levels" 
 run from the shaft from time to time as it is deepened; 
 and are distinguished from "tunnels," which have one 
 end open at the surface the distinction between a 
 tunnel and a drift being the same as between a shaft 
 and a winze. The face of the drift is called the 
 "head" or "heading ;" ground from which ore is being 
 taken between the different levels is called a "stope," 
 and the ore may be removed either by digging down- 
 ward, when the process is called "underhand sto- 
 ping," or by working upward, in which case the 
 operation is said to be "overhand" or "overhead." 
 It is evident that by the latter method the material 
 when broken down drops away from the workman more 
 readily than by the former, and is usually the one em- 
 ployed, unless circumstances absolutely prevent its 
 economical adoption. The timbers which are put in 
 to keep the walls apart after the extraction of the ore, 
 
EA RL Y DE VEL OP MEN T OF MINES. 205 
 
 and also to form working floors for the miners, are 
 called "stulls," and the filling done with the waste 
 material (in Cornwall Battle"), which is never taken 
 from the mine, if possible to utilize it, is called the 
 "gob. " When taken to the surface it forms the 
 " waste dump." An excessively large dump of waste 
 material indicates an excess of dead work in the mine; 
 a small one on the other hand is by no means a bad 
 gage of prosperity. The bottom of shafts, inclines 
 and winzes into which the water of the mine drains, 
 and in which the pumps are located, is known as the 
 "smnp, " and is necessarily below the lowest working 
 level, its depth being gaged according to the amount 
 o^ water to be removed daily. 
 
CHAPTER XIII. 
 
 ORES. 
 
 DEFINITIONS. An "ore," strictly speaking, isasingle 
 mineral which is a chemical compound of a useful 
 metal and some other element or acid. In common 
 usage, however, complex mixtures of pure minerals are 
 considered arj single ores; while free gold, native 
 silver and native copper, together with their accom- 
 panying gangue minerals, are also classed as ore. 
 Among miners whatever will pay to treat or ship and 
 sell is considered ore, as also low-grade mineral which 
 might be utilized by concentration or improved facili- 
 ties; but there is an indefinite shading off into mate- 
 rial containing traces of ore minerals but hopelessly 
 unavailable, and this is not considered ore; neither are 
 gold gravel or platinum sands called ore. To avoid 
 misunderstanding, it is best to distinguish between the 
 "ore" (meaning thereby the whole bulk of the available 
 product) and the "ore mineral" (usually very much 
 smaller in quantity in all ores except those of iron, 
 manganese, and some lead and zinc ores). In this 
 connection will be mentioned only those minerals 
 which produce the bulk of the useful metals. Min- 
 eralogists describe some 850 different mineral species, 
 of which a considerable proportion might possibly be 
 called ores; but only a comparatively few are of prac- 
 tical importance the remainder are of interest only 
 to the collector and scientist. It is believed thao 
 those here described will be sufficient to enable the 
 
ORES. 207 
 
 prospector to recognize nearly all which are commer- 
 cially valuable. 
 
 The descriptions are based on those in Dana's "Min- 
 eralogy," and are supposed to apply to the minerals 
 in their pure, crystallized forms, but such items as 
 hardness, weight, color and streak are common also 
 to the massive forms. To make the descriptions short 
 and compact a few terms and contractions are em- 
 ployed, which need explanation : 
 
 Adamantine, resembling a diamond. 
 
 Amorphous, not crystallized; without any special 
 form. 
 
 Arborescent, resembling the growth of the branches 
 of a tree. 
 
 Botryoidal, made up of masses of varying size with 
 smooth rounded surfaces, like grapes. 
 
 Brilliant, applied to surfaces which are perfect 
 reflectors of lighto 
 
 Brittle, breaking easily. 
 
 Compact, very close-grained, not showing special 
 crystals. 
 
 Conchoidal, as applied to surfaces of fracture, 
 means resembling the inside of a clam' shell in shape. 
 
 Concretionary, made up of particles which have 
 apparently grown together into a solid mass. 
 
 Ductile, capable of being drawn out into wire, or 
 elongated. 
 
 Flat, as applied to fracture, means smooth, like a 
 board. 
 
 Fibrous, like a bundle of threads laid side by side. 
 
 Filiform, thread-like, not massed together as when 
 fibrous. 
 
 Foliated, made up of thin leaves like a book. 
 
 Granular, made up of distinct grains like coarse 
 sandstone. 
 
 Iridescent, exhibiting a play of changeable rainbow 
 colors. 
 
 Malleable, flattening under the hammer without 
 breaking. 
 
208 PROSPECTING AND VALUING MINES. 
 
 Mammillary, made up of many small rounded sur- 
 faces like miniature breasts; usually applied to some 
 forms of incrustations on rocks. 
 
 Massive, not crystallized. 
 
 Metallic, when descriptive of luster, means resem- 
 bling polished steel, silver or other metals, as opposed 
 to "earthy." 
 
 Micaceous, made up of thin plates, resembling flakes 
 of mica. 
 
 Oolitic (o-o-litic), made up of rounded particles, like 
 fish eggs. 
 
 Opaque, will not permit the passage of light. 
 
 Pisolitic, made up of rounded particles like peas. 
 
 Eeniform, kidney-shaped. 
 
 Resinous, resembling resin. 
 
 Sectile, can be cut with a knife, like lead or easier. 
 
 Shining, opposed to "earthy," when describing the 
 "streak." 
 
 Stalactitic, resembling the cylindrical masses found 
 hanging from the roof of limestone caves, formed by 
 dripping water. 
 
 Subconchoidal, resembling conch oidal, but flatter, 
 more like the inside of an oyster shell in form. 
 
 Submetallic, with only a slight metallic luster, as a 
 tarnished silver surface. 
 
 Translucent, not perfectly clear, but resembling an 
 egg when held up before a strong light. 
 
 Transparent, permitting the perfect passage of 
 light, like glass. 
 
 Uneven, breaking into a rough face, like a broken 
 brick. 
 
 Vitreous, glassy. 
 
 Waxy, as applied to luster, not quite so bright as 
 resinous, resembling the surface of clean beeswax. 
 
 It would not be possible to give a good idea of the 
 forms assumed by the crystallized minerals without 
 numerous diagrams, so that only occasional references 
 are made to crystallization, The physical properties 
 
ORES. 209 
 
 used are the luster, color, streak, hardness, weight, 
 and manner of breaking. By the "streak/' is meant 
 the color of the scratch made by a penknife or the 
 color of the powdered mineral. The weight is the 
 specific gravity (in ratio to weight of equal bulk of 
 water), indicated by the letter G, and is an important 
 item in all concentrating operations or the sorting of 
 ores. The hardness, indicated by the letter H, refers 
 to a scale of hardness, in common use, in which crys- 
 tallized varieties of the minerals mentioned are meant: 
 1, talc; 2, gypsum; 3, calcite or limespar; 4, fluor- 
 spar; 5, apatite; 6, feldspar; 7, quartz; 8, topaz; 9, 
 corundum; 10, diamond; so that if a mineral is said 
 to have a hardness of 4 it would scratch 3, but would 
 not scratch 5. 
 
 GOLD Native. H. 2.53. G. 15.619.5. Yel- 
 low, malleable, sectile. The depth of the yellow color 
 varies with the amount of silver present in the metal, 
 being deepest in the purest gold. When the value in 
 silver becomes equal to the value of the gold, the 
 native alloy is white. Distinguished from all minerals 
 which it resembles, by flattening under the hammer, 
 instead of breaking. The minerals for which it is 
 most frequently mistaken are iron and copper pyrites, 
 but it may be distinguished from these, when in such 
 a position that it cannot be tested by the knife or 
 hammer, by turning the specimen completely round in 
 the sunlight, when it will be found to maintain the 
 same color and appearance in every position. This is 
 not the case with the other minerals mentioned, which 
 will also float on the top of quicksilver, while gold 
 will sink. Insoluble in simple acids. Distinguished 
 from yellow mica by not splitting. 
 
 Tellurides of Gold. These minerals are not found 
 in large quantities, but are associated with other ores, 
 and from their want of resemblance to gold often 
 puzzle the prospector, who will get very large assays 
 from samples which show no free gold. The four 
 
210 PROSPECTING AND VALUING MINES. 
 
 forms may be distinguished by the following char- 
 acters. Three of them greatly resemble lead, and none 
 of them are common enough to have local names. The 
 important tellurides carrying gold are: 
 
 Sylvanite.H. 1.52. G. 7.98.3. Luster me- 
 tallic. Streak and color steel-gray to silver-white, 
 sometimes brass-yellow. Fracture uneven. Approxi- 
 mate composition: gold 30, silver 10, tellurium 60%. 
 
 Nagyagite.H. 11.5. G. 6.87.2, Luster me- 
 tallic, brilliant. Streak and color blackish lead-gray. 
 Opaque. Sectile. Composition: 6 to 12% of gold 
 with lead and tellurium. 
 
 Petzite.R. 2.5. G. 8.89.4. Color between 
 steel-gray and iron-black, sometimes tarnished with 
 peacock tints. Streak iron-black. Brittle. Approxi- 
 mate composition : gold 25, silver 41, tellurium 34%. 
 
 Calaverite. Massive, without crystalline structure; 
 color bronze-yellow; streak yellowish gray; brittle. 
 Fracture uneven. Approximate composition: gold 
 41, silver 3, and tellurium 56%. 
 
 SILVER Native. H. 2.53. G. 10.5. Luster 
 metallic. Color and streak silver-white. Ductile. 
 Tarnishes easily to grayish black. Malleable. Occurs 
 as wire silver, crystallized (arborescent) or massive, 
 up to 800 Ib. in weight. 
 
 Argenlite, Silver Sulphide, Vitreous Silver, or Silver 
 Glance. H. 22.5. G. 7.27.4. Luster metallic. 
 Streak and color blackish lead-gray; streak shining. 
 Opaque. Perfectly sectile. Occuis crystallized, 
 amorphous, arborescent and filiform. Approximate 
 composition; silver 85, sulphur 15%. Gives silver 
 when heated on charcoal before the blowpipe. 
 
 Pyrargyrite, Dark Ruby or Antimonial Ruby Silver. 
 H. 22.5. G. 5.8. Luster metallic. Color 
 black, sometimes approaching dark or purplish red. 
 Streak cochineal-red. Translucent to opaque. Frac- 
 ture conchoidal. Powder purplish red. Approxi- 
 mate composition : silver 60, antimony 22, sulphur 
 18%. Decomposed by nitric acid. 
 
ORES. 211 
 
 Proustite, Light Red or Arsenical Ruby Silver.* H. 
 2 2.5. G. 5.5. Luster adamantine. Color cochi- 
 neal-red. Streak cochineal-red sometimes brighter. 
 Subtranslucent. Fracture conchoidal, uneven. Pow- 
 der bright red. Approximate composition ; silver 65, 
 arsenic 15, sulphur 20%. Decomposed by nitric acid. 
 
 Freieslebenite or Gray Silver Ore. H. 2 2.5. G. 
 6 6.4. Luster metallic. Color and streak light 
 steel-gray, inclining to silver-white, also blackish 
 lead-gray. Yields easily to the knife, and is rather 
 brittle. Fracture uneven. Powder steel-gray Ap- 
 proximate composition ; silver 22, lead 30, antimony 
 28, sulphur 18, iron and copper 2%. 
 
 Stephanite, Brittle or Black Silver. H. 22.5. G. 
 6.3. Luster metallic. Color, streak and powder 
 iron-black. Fracture uneven. Approximate composi- 
 tion; silver 68.5, antimony 15, sulphur 16.5%o Solu- 
 ble in heated dilute nitric acid. 
 
 Cerargyrite, Horn Silver or Chloride of Silver. H. 
 1 1.5. G. 5.5. When nearly pure, looks like wax. 
 Luster resinous. Color pearl-gray, grayish green, 
 whitish, rarely violet-blue, sometimes colorless when 
 perfectly pure; brown, or violet-brown after exposure. 
 Streak shining. Translucent. Sectile, cuts like wax. 
 Not soluble in nitric acid. A fragment placed on a 
 strip of zinc, and moistened with a drop of water, 
 swells up, turns black and finally is entirely reduced 
 to metallic silver, which shows the metallic luster on 
 being pressed with the point of a knife. Composition : 
 silver 75.3, chlorine 24.7%. 
 
 Embolite or Bromide of Silver. H. 1 1.5. G. 5.5. 
 Eesembles horn silver. Luster resinous. Color 
 usually greener than horn silver, often dark, becom- 
 ing darker on exposure. Composition : silver 67, 
 chlorine 13, bromine 20%. 
 
 (Besides the above, there are some 20 other silver 
 minerals of small importance commercially.) 
 
 PLATINUM Native. H. 44.5. G. 1619. Luster 
 
212 PROSPECTING AND VALUING MINES. 
 
 metallic, not very bright; color and streak -whitish 
 steel-gray; shining. Opaque. Ductile. Malleable. 
 Occurs usually in small grains; occasionally in masses 
 of several pounds weight. Infusible. Soluble only 
 in heated nitro-muriatic acid. 
 
 IRIDOSMINE Native.' H. 6 7. G. 19 21. Lus- 
 ter metallic. Color tin-white and light steel-gray. 
 Opaque. Malleable with difficulty. Composition : 
 the metals iridium and osmium in varying propor- 
 tions, in combination with small amounts of rhodium, 
 platinum and ruthenium. Occurs as small flattened 
 grains in gold washings. 
 
 QUICKSILVER OR MERCURY Native. G. 13.56. Fluid. 
 Luster metallic. Color tin-white. Opaque. 
 
 Cinnabar or Sulphide of Mercury. H. 2. G. 9.0. 
 Luster adamantine, inclining to metallic when dark 
 colored, and to dull in friable varieties. Color cochi- 
 neal-red to brownish red and lead-gray. Streak 
 scarlet; subtransparent to opaque. Fracture uneven. 
 Powder bright scarlet, being the article known as ver- 
 milion. Composition: quicksilver 86.2, sulphur 
 13.8%. 
 
 Metacinnabarite. A dark to blackish variety of 
 cinnabar. H. 2.5. G. 8.19. Luster metallic to dull. 
 Color steel-gray or blackish lead-gray. Streak nearly 
 black. Opaque. 
 
 There are a number of combinations of mercury 
 with selenium, chlorine and iodine which are of small 
 commercial value. 
 
 COPPER. All the following minerals marked with 
 an asterisk (*) are dissolved in nitric acid, and will 
 deposit red metallic copper on polished iron dipped 
 into the solution. 
 
 * Native. H. 2.53. G. 8.84. Luster metallic. 
 Color copper-red. Streak metallic and shining. 
 Ductile and malleable. 
 
 * Chalcopyrite or Copper Pyrite. H. 3.5 4. G. 
 4.2. Luster metallic. Color brass-yellow; subject to 
 
ORES. 213 
 
 tarnish and often iridescent. Streak greenish black 
 a little shining. Opaque. Fracture conchoidal, un- 
 even. Powder greenish-black. Varies in the inten- 
 sity of the yellow color, when massive, according to 
 the amount of iron pyrite in the ore, becoming paler 
 in proportion. It may be distinguished from iron 
 pyrite also by being much softer and easily scratched 
 with a knife. Composition when pure: copper 34, 
 iron 30, sulphur 36%. 
 
 *Cubanite, a Copper Pyrite. Similar to chalcopyrite. 
 H. 4.0. G. 4.0. Cleavage rather more distinct than 
 in ordinary pyrite. Massive. Color between bronze 
 and brass-yellow. Streak dark reddish bronze to 
 black. Composition; copper 21, iron 39, sulphur 39% 
 with a little silica. 
 
 *Barnhardite > a Copper Pyrite. Similar to chalco- 
 pyrite. H. 3.5. G. 4.5. Compact, massive. Luster 
 metallic. Color bronze-yellow. Streak grayish 
 black, slightly shining. Fracture conchoidal, uneven. 
 Brittle. Tarnishes easily to peacock tints, or becom- 
 ing brown. Composition : copper 48, iron 22, sulphur 
 30%. 
 
 *Bornite, Purple, Variegated, Horseflesh or Peacock 
 Copper. H. 3.0. G. 4.5 5.5. Massive, structure 
 granular or compact. Luster metallic. Color between 
 copper-red and pinchbeck-brown; tarnishes easily to 
 red, blue and purple tints. Streak and powder pale 
 grayish black. Brittle. Easily scratched with a 
 knife. Approximate composition : copper 58, iron 15 5 
 sulphur 27%. 
 
 *Chalcocite or Vitreous Copper. H. 2.5 3.0. Go 
 5.6. Luster metallic. Color, streak and powder 
 dark lead-gray ; often tarnishes blue or green. Streak 
 sometimes shining. Resembles some silver ores, but 
 gives copper instead of silver when heated on char- 
 coal. Approximate composition : copper 78, iron 2, 
 sulphur 20%. 
 
 * Tetrahedrite or Gray Copper. H. 3,0- 4.5. G. 
 
PROSPECTING AND VALUING MINES. 
 
 4o5 5.L Luster metallic. Color between light 
 flint-gray and iron-black. Streak and powder gen- 
 erally the same, sometimes inclining to brown and 
 cherry-red. Opaque. Bather brittle. Fracture sub- 
 conchoidal, uneven. This is a very complex ore, 
 carrying not infrequently a valuable amount of silver. 
 Ordinary composition: copper 30 to 40; antimony 15 
 to 25; sulphur 20 to 25%; with iron, arsenic, zinc, 
 silver, and sometimes mercury. In forty-seven 
 analyses given by Dana, the silver contents range from 
 a trace to 17%, and in one instance 31%, replacing 
 copper or iron. 
 
 * Cuprite or Red Oxide of Copper. H. 3.5 4.0. G. 
 5.8 6.0. Luster adamantine or submetallic to earthy. 
 Color red of various shades, particularly cochineal- 
 red ; occasionally crimson red by transmitted light. 
 Streak and powder several shades of brownish red. 
 Streak shining. Subtransparent to subtranslucent. 
 Brittle. Fracture subconchoidal, uneven. Compo- 
 sition when pure: copper 88.8, oxygen 11.2%. 
 
 *Melaconite or Black Oxide of Copper. H. 3.0. G. 
 6 6.2. Usually massive or as an earthy powder. 
 Luster metallic, and color steel or iron-gray when in 
 thin scales; dull and earthy, with a black or grayish 
 black color, and ordinarily soiling the fingers when 
 massive or powdery. Composition: copper 79.85, 
 oxygen 20.15%. 
 
 * Malachite or Green Carbonate of Copper. H. 3.5 
 4. G. 3.74. Luster of crystals adamantine, inclin- 
 ing to vitreous; of fibrous varieties, silky; often dull 
 and earthy. Color bright green. Streak paler green. 
 From translucent to opaque. Fracture subconchoidal, 
 uneven. About 62% copper; remainder carbonic 
 acid, oxygen and water. 
 
 *Azurite or Blue Carbonate o f Copper. H. 3.5 4.2. 
 G. 3.5 3.8. Crystallized or massive, also dull and 
 earthy. Luster vitreous. Color various shades of 
 azure blue passing into dark blue. Streak blue, 
 
ORES. . 215 
 
 lighter than the color. Fracture conchoidal. Brittle. 
 Partially translucent when crystallized. About 61% 
 copper, remainder carbonic acid, oxygen and water. 
 
 Chrysocolla or Copper Silicate. H. 2.0 4.0. G. 
 2.1. Slightly crystalline; often opal-like or enamel- 
 like in texture ; earthy. In seams or crusts. Some- 
 times botryoidal. Luster vitreous, shining, earthy, 
 Color green, bluish green passing into sky and tur- 
 quoise-blue; brown to black when impure. Streak 
 when pure, white. Translucent to opaque. Rather 
 sectile; translucent varieties brittle. Eesembles the 
 green carbonate, but is paler green, usually has a 
 coarser texture (is never fibrous), a smoother surface, 
 somewhat waxy luster, and is usually an incrustation 
 upon other ores. About 35% copper; remainder 
 silica, oxygen, water and small amount of iron oxide. 
 
 Ata':amite or Chloride of Copper. H. 3.0 3.5. G. 
 3.7 4.3. Luster adamantine to vitreous. Color vari- 
 ous shades of bright green, rather darker than emerald, 
 sometimes blackish green. Streak apple-green. 
 Somewhat translucent. Composition: about 58% 
 copper; remainder oxygen, chlorine and water. 
 
 Chalcocite, Sulphate of Copper, Bluestone. H. 2.5. 
 G. 2.2. Crystallized. Luster vitreous. Color shades 
 of blue from sky to darker; sometimes greenish blue. 
 Streak uncolored. Taste metallic. Brittle. Sub- 
 translucent. About 38% copper; remainder oxygen, 
 sulphuric acid and water. Soluble in water. 
 
 (In addition to the foregoing, there are of the 
 rarer copper minerals some 21 combinations with sulr 
 phur and arsenic; two with silica; 26 with phosphoric, 
 arsenious or sulphuric acids; and tw 7 o other carbon- 
 ates. They are, however, only mineral curiosities. 
 The total number of copper-bearing minerals is about 
 65.) 
 
 LEAD Native. H. 1.5. G. 11.44 when pure. Lus- 
 ter metallic. Color lead-gray. Malleable and ductile. 
 
 Galenite, Galena or Lead Sulphide. H. 2. 5, G, 
 
216 PROSPECTING AND VALUING MINES. 
 
 7.2 7.7. Luster metallic. Color and streak lead- 
 gray. Surface of crystals occasionally with bluish 
 tarnisho Fracture flat, subconchoidal or even. Very 
 brittle. Soluble in nitric acid. Yields lead or char- 
 coal. Crystallizes in cubes. Composition : lead 86.6, 
 sulphur 13.4%. The chief ore of lead; usually carries 
 some silver, often some antimony. 
 
 Cerussite or Lead Carbonate. H. 3.0 3.5. G. 5.4 
 6.4. Crystallized or earthy. Luster adamantine, 
 inclining to vitreous or resinous; sometimes pearly; 
 sometimes submetallic if the colors are dark or from 
 superficial change. Color white, gray, grayish black, 
 sometimes tinged blue or green by traces of copper. 
 Streak uncolored. Fracture conchoidal; very brittle. 
 Subtranslucent; usually opaque when massive. Be- 
 sults from the alteration of galena, which often forms 
 the core of massive varieties. Composition : lead 
 about 70%, remainder oxygen, carbonic acid and 
 impurities. 
 
 Pyromorphite or Lead Phosphate. H. 3.5 4.0. G. 
 6.5 7.1; when containing lime 5.0 6.5. Luster 
 resinous. Color green/yellow and brown, of differ- 
 ent shades; sometimes wax-yellow and fine orange- 
 yellow; also grayish white to milk-white. Streak 
 white, sometimes yellowish. Subtranslucent. Brit- 
 tle. Fracture subconchoidal, uneven. Occurs only 
 with other ores. Composition : very variable, con- 
 taining phosphates of lead and lime, chloride of lead, 
 fluoride of lime and arsenic. 
 
 Anglesite or Lead Sulphate. H. 2.753. G. 6.2, 
 Luster highly adamantine, sometimes inclining to 
 resinous and vitreous. Color white, tinged yellow, 
 gray, green and sometimes blue. Streak uncolored. 
 Transparent to opaque. Fracture conchoidal. Very 
 brittle. Occurs massive, crystallized or stalactitic. 
 Composition: lead, about 64%; remainder oxygen 
 and sulphuric acid. Easily fusible. 
 
 Massicot or Lead Oxide, H. 2.0* GK 8,09,0, 
 
ORES. 217 
 
 Luster dull. Color between sulphur and orange- 
 yellow, sometimes reddish. Opaque. Massive or 
 earthy. Composition: lead 92.83, oxygen 7.17. 
 
 Minium or Red Oxide of Lead. H. 2.0 3.0. G. 
 4.6. Powdery. Luster dull or slightly greasy. 
 Color bright red, mixed with yellow ; streak orange- 
 yellow, Opaque. Composition: lead 90.66, oxygen 
 9.34%. 
 
 These oxides do not yield much commercial lead, 
 but are given as they often occur as powdery matter 
 in the so-called "chloride" ores of the miners. 
 
 (Besides the above there are some 40 non-cornmer- 
 cial lead minerals, in which lead is combined with 
 sulphur, antimony, chlorine and oxygen ; or with ar- 
 senious, antirnonious, phosphoric, tungstic, molybdic, 
 vanadic, sulphuric, chromic, selenious and carbonic 
 acids. Several of these, such as the molybdate of 
 lead (wult'enite) and the vanadate of lead, are beau- 
 tiful waxy minerals of various shades of color from 
 lemon-yellow to red, occurring usuall3 r in crystallized 
 forms, making beautiful cabinet specimens but not 
 otherwise specially valuable). 
 
 ZINC Smithsonite, Drybone or Zinc Carbonate. H. 
 5.0. G. 4 4.4. Occurs crystallized, reniform, botry- 
 oidal or stalactitic and as incrustations; also granular 
 and sometimes earthy and powdery. Luster vitreous, 
 inclining to pearly. Color white, often grayish, 
 greenish, brownish white, sometimes green and brown. 
 Streak white. Brittle, Fracture uneven. Approxi- 
 mate composition : zinc 52%, remainder oxygen and 
 carbonic acid. Usually carries small quantities of 
 lead and iron. 
 
 Calamine or Zinc Silicate. H. 4.5 5.0. G. 3.5. 
 Occurs crystallized, stalactitic, botryoidal and 
 fibrous; also massive and granular. Luster vitreous. 
 Color white, sometimes with -a delicate blueish or 
 greenish shade; also yellowish to brown. Streak 
 white. Fracture uneven. Brittle. Contains 67.5% 
 oxide of zinc. 
 
218 PROSPECTING AND VALUING MINES. 
 
 (The last two minerals are very much alike in their 
 general appearance, but smithsonite is soluble in 
 muriatic acid, while calami tie forms a gelatinous mass 
 under the same conditions, and is soluble in strong 
 caustic potash.) 
 
 Zincite or Red Zinc Oxide. R. 4.04.5. G. 5.6 
 Usually in foliated grains, or coarse particles and 
 masses; also granular. Luster subadamantiue. Color 
 orange-yellow to deep red. Streak orange-yellow. 
 Brittle. Fracture uneven. Subtransluceut. Com- 
 position: zinc 80.26, oxygen 19.74%, usually contain- 
 ing small quantities of manganese. 
 
 Blende, Zincblende, Zinc Sulphide or Blackjack. 
 H. 3.54.0. G. 3.94.2. Luster resinous to 
 adamantine. Color brown, yellow, black, red, green; 
 wlaite or yellow when pure. Streak white to reddish 
 brown. Powder nearly white, even in dark varieties. 
 Fracture conchoidal. Brittle. Translucent to 
 opaque. Crystallized or massive. Composition: zinc 
 67, sulphur 33%. Distinctly clearable. 
 
 Franklinite.lA. 5.56.5. G. 5.60. Crystallized 
 and massive, either granular or compact. Luster 
 metallic. Color iron-black. Streak dark reddish 
 brown e Opaque. Brittle. Fracture conchoidal. 
 Acts slightly on the magnet. Soluble in muriatic 
 acid. Approximate composition : zinc oxide 18, 
 manganese oxide 16, iron oxide 66%, the proportions 
 of zinc and manganese varying considerably. 
 
 Willemite, a Zinc Silicate. H. 5.5. G. 4.0. Crys- 
 tallized massive or in grains; sometimes fibrous. 
 Luster resinous. Color whitish or greenish yellow 
 when purest; apple-green, flesh-red, grayish white, 
 yellowish brown ; often dark brown when impure. 
 Streak uncolored. Transparent to opaque. Brittle. 
 About 58% zinc; remainder oxygen and silica. Car- 
 ries small quantities of iron and manganese. 
 
 (Besides the above there are some 15 other zinc- 
 bearing minerals of minor importance.) 
 
ORES. 
 
 IRON Magnetite or Magnetic Iron Ore. H. 5.5 
 6.5, G. 5.18. Luster metallic to subrnetallic. Color 
 and streak iron-black. Opaque. Fracture subcon.- 
 choidal, shining. Brittle. Strongly magnetic, 
 sometimes possessing polarity, like the needle of a 
 compass. Composition: iron 72.4, oxygen 27.6%. 
 
 Hematite or lied Oxide of Iron, or Specular Iron 
 Ore. H. 5.5 6.5. G. 4.2 5.3. Crystallized, colum- 
 nar, granular, botryoidal and stalactitic, as well as 
 micaceous and compact. Luster of crystals me- 
 tallic, sometimes brilliantly so; sometimes earthy. 
 Color dark steel-gray or iron-black ; when earthy 
 inclined to red. Streak cherry-red or reddish brown. 
 Opaque. Fracture subconchoidal, uneven; some- 
 times slaty. Sometimes attractable by the magnet. 
 Composition : iron 70, oxygen 30%. Varies consid- 
 erably in its mode of occurrence and outward appear- 
 ance. When excessively lustrous and brilliant it is 
 known as "specular iron ore;" when in .thin flakes 
 and foliated, "micaceous iron ore;" when compact 
 or fibrous with a reddish brown or iron-black color, 
 "red hematite;" or "clay iron ore" when mixed with 
 earthy impurities, and possessing an earthy appear- 
 ance and no luster, with not infrequently a deep dull 
 red color. 
 
 Limonite, Brown Hematite or Bog Iron Ore. H, 5.0 
 5.5. G. 3.6 4.0. Usually in stalactitic and 
 botryoidal forms, having a more or less fibrous struc- 
 ture; also concretionary, massive and occasionally 
 earthy. Luster silky, often submetallic; sometimes 
 dull and earthy. Color of surface of fracture various 
 shades of brown, commonly dark, and none bright; 
 sometimes with a nearly black varnish-like exterior; 
 when earthy, brownish yellow to yellow ocher. 
 Streak yellowish brown. Composition : differs from 
 hematite in carrying about 16% of water. The term 
 "bog" ore is applied to the modern formations found 
 in marshy places, which usually conteJu manganese as 
 an impurity. 
 
220 PROSPECTING AND VALUING MINE8. 
 
 (The three foregoing minerals produce the bulk of 
 the iron of commerce. They can readily be distin- 
 guished from each other by the streak, which is 
 respectively black, red or yellowish brown. The 
 following minerals, while strictly iron ores, are valu- 
 able chiefly for their other constituents such as zinc, 
 chrome, sulphur, arsenic, etc., and the precious metals 
 found in their company.) 
 
 Franklinite. Described with the zinc minerals. 
 
 Sidemte, Spathic Iron or Iron Carbonate. H. 3.5 
 4.5. G. 3.8. Occurs crystallized; also in botryoidal 
 and globular forms, somewhat fibrous within, occa- 
 sionally silky. Often massive. Luster vitreous, more 
 or less pearly. Color ash-gray, greenish gray, also 
 brown and reddish brown, rarely green; sometimes 
 white. Fracture uneven. Brittle. Streak white. 
 Composition: oxide of iron 62.1, carbonic acid 
 37.9%. 'Usually carries manganese, magnesia and 
 lime as impurities. A sparry looking ore, distinctly 
 cleavable, turning brown to black on exposure. A 
 good ore of iron when abundant. 
 
 Pyrite, Iron Pyrite or Iron Sulphide. H. 6.0 
 6.5. G. 4.8 5.2. Crystallized or massive. Luster 
 metallic, splendent to glistening. Color a pale 
 brass-yellow nearly uniform. Streak greenish or 
 brownish black. Opaque. Fracture conchoidal, 
 uneven. Brittle. Strikes fire with steel. Composi- 
 tion (omitting impurities): iron 46.7, sulphur 53.3%. 
 Crystallizes in cubes. The pyrites of gold regions 
 usually carry gold, which may be occasionally seen 
 projecting from the faces of the crystals. Other 
 varieties carry small quantities of nickel, cobalt, silver 
 or tin. Pyrite is one of the commonest of minerals, 
 and aside from the precious metals it contains, is 
 chiefly used in the manufacture of sulphuric acid, the 
 acid being produced more cheaply by this method than 
 from sulphur direct. 
 
 -' Similar to ordinary pyrite in composi- 
 
ORES, 221 
 
 tion, but differs in the form of the crystals, which are 
 often flat and crested. H. 6.06.5. G. 4.8. Crys- 
 tallized, globular or reniform ; often massive or gran- 
 ular. Luster metallic. Color pale bronze-yellow, 
 sometimes inclined to green or gray. Streak grayish 
 or brownish black. Fracture uneven. Brittle. Often 
 carries gold. 
 
 Pyrrhotite or Magnetic Iron Pyrite. H. 3.5 4.5. 
 G. 4.6. Commonly massive or granular. Luster 
 metallic. Color between bronze-yellow and copper- 
 red, and tarnishing easily. Streak dark grayish 
 black. Brittle. Magnetic, being attracted in fine 
 powder by a magnet, when not affecting a magnetic 
 needle. This ore is valuable chiefly for the nickel it 
 contains, which in some cases ranges from 3 to 5%, 
 and furnishes the bulk of the nickel of commerce. 
 Composition: iron 60.5, sulphur 39. 5%. 
 
 Mispickel or Arsenical Parties. H. 5.5 6.0. G. 
 6.0 6.4. Luster metallic. Color silver-white, in- 
 clining to steel-gray. Streak dark grayish black. 
 Fracture uneven. Brittle. Composition: iron 34.4, 
 sulphur 19.6, arsenic 46.0%. This mineral is the 
 source of the bulk of the arsenic of commerce, as well 
 as cobalt, and is associated with and frequently carries 
 silver and gold in small quantities. 
 
 llmentie or Titanic Iron. H. 5.06.0. G. 4.5- 
 5.0. Massive or as loose grains in sand. Luster 
 submetallic. Color iron-black. Streak submetallic, 
 powder black to brownish red. Opaque. Fracture 
 conchoidal. Slightly influencing the magnetic 
 needle. Composition : oxide of iron with varying 
 amounts of titanium, 3 to 30%. Not a true iron ore. 
 
 (Besides the above there are nearly 40 other non- 
 commercial iron minerals, consisting of silicates, sul- 
 phates, phosphates, arsenates, carbonates, etc.) 
 
 MANGANESE Manganite. H. 4.0. G. 4.3. Occurs 
 crystallized, stalactitic, seldom granular. Luster sub- 
 metallic. Color dark steel-gray to iron-black. Streak 
 
222 PROSPECTING AND VALUING MINES. 
 
 and powder reddish brown, sometimes nearly black. 
 Opaque. Fracture uneven. Composition: manganese 
 62.5, oxygen 27.3, water 10.2%. 
 
 Pyrolusite, Manganese Dioxide. H. 2.0 2.5. G. 
 4.8, Luster metallic. Color iron-black, dark steel- 
 gray, sometimes bluish. Streak black or bluish 
 black, sometimes submetallic. Opaque. Bather brit- 
 tle. Composition: manganese 63.3, oxygen 36.7%. 
 One of the most important ores of manganese; it is 
 easily distinguished from psilomelane by its inferior 
 hardness, and being usually crystalline; from rnan- 
 ganite, by the color of the streak and powder. Often 
 soils the hands. 
 
 Psilomelane or Black Manganese Oxide. H. 5.0 6.0. 
 G. 3.7 4.7. Occurs massive and botryoidal s reniform 
 and stalactitic. Luster submetallic. Color iron- 
 black, passing into dark steel-gray. Streak brownish 
 black, shining. Opaque. Composition : an oxide of 
 manganese (variable in quantity) with oxide of bar- 
 ium, and several other impurities in minor quantities. 
 Not being found crystallized the exact nature of the 
 species is yet doubtful. 
 
 Wad or Bog Manganese. The ores included under 
 this name occur in amorphous and reniform masses, 
 either earthy or compact, and sometimes incrusting. 
 They are mixtures of different oxides and cannot be 
 considered a distinct species. H. 0.5 6.0. G. 3.0 
 4.2, often loosely aggregated and feeling very light 
 to the hand. Color dull black, bluish or brownish 
 black. Composition: manganese oxide, with iron, 
 barium, cobalt and copper oxides in varying propor- 
 tions. 
 
 (There are, in addition to the above, some 20 other 
 unimportant manganese minerals.) 
 
 TixCassiterite or Tin Oxide. H. 6.07.0. G. 
 6.4 7.1. Occurs crystallized and massive. Luster 
 adamantine, and crystals usually splendent. Brown 
 or black; sometimes rod, gray, white or yellow. 
 
ORES.. 223 
 
 Streak white, grayish, brownish. Crystals nearlj r 
 transparent, sometimes opaque when massive. Frac- 
 ture subconchoidal, uneven. Brittle. Composition : 
 tin 78.67, oxygen 21.33%'. Furnishes the tin of com- 
 merce. Does not look much like a metallic ore and is 
 often confounded with the valueless mineral epidote. 
 Only slightly acted on by acids. Detected usually by 
 its weight. 
 
 Stream tin is nothing but the ore in the state of 
 sand, as it occurs in the gravel derived from the 
 decomposition of the rocks carrying the ore. 
 
 Wood tin is an irony-looking mineral, a variety of 
 cassiterite, very heavy, occurring in rounded, botry- 
 oidal or reniform shapes, concentric in structure, and 
 radiated fibrous internally, although very compact, 
 with the color brownish, and the rings of mixed shades, 
 looking somewhat like dry wood. Occurs in the 
 gravel of streams. 
 
 Stannite or Tin Sulphide. H. 4. G. 4.4. Com- 
 monly massive, granulated, or disseminated through 
 the rock in small grains. Luster metallic. Color 
 steel-gray to iron-black, the former when pure. Streak 
 blackish. When copper pyrite is present in the ore 
 the color is often yellowish. Opaque. Brittle. Frac- 
 ture uneven. Composition: tin 27.2, copper 29.3, 
 sulphur 29.6, iron 6.5, zinc 7.5%. It frequently has 
 the appearance of bronze or bell metal, and is hence 
 called "bell metal" ore. 
 
 (Tin is found in small quantities as a component of 
 several other ores.) 
 
 CHROMIUM (Jhromite or Chrome Iron. H. 5.5. 
 G. 4.4. Usually occurs massive; structure fine gran- 
 ular or compact. Luster submetallic. Streak brown. 
 Color between iron-black and brownish black. Opaque. 
 Brittle. Fracture uneven. Sometimes magnetic. 
 Composition: oxide of chromium 68, oxide of iron 
 32%. Usually with alumina and silica as impurities 
 when massive. The ore has usually green incrusta- 
 
PROSPECTING AND VALUING MINES. 
 
 tions in the seams which distinguish it readily from 
 the other iron ores. Affords the chrome of commerce, 
 not being used as an iron ore. 
 
 (Several other ores contain chromium, but not in 
 available quantities.) 
 
 NICKEL Pyrrhotite or Magnetic Iron Pyrite. (See 
 iron ores). The chief source of nickel. 
 
 Niccolite, Copper-nickel or Arsenical Nickel. - 
 Usually massive, no visible structure; also reniform 
 and arborescent. H. 5.0 5.5. G. 7.5. Luster me- 
 tallic. Color pale copper-red, with a gray to blackish 
 tarnish. Streak pale brownish black. Opaque. 
 Brittle. Composition: nickel 44.1, arsenic 55.9%; 
 sometimes part of the arsenic is replaced by antimony, 
 with small quantities of lead, cobalt and sulphur. 
 Kesembles pyrrhotite or magnetic iron pyrite, but 
 is not magnetic. 
 
 Gersdorffite or Nickel Glance C rystallization 
 cubic; also lamellar and granular massive, H. 5.5. 
 G. 5.6 6.9. Luster metallic. Color silver-white to 
 steel-gray, often tarnished gray or grayish black. 
 Streak grayish black. Fracture uneven. Composi- 
 tion : nickel 35.1, arsenic 45.5, sulphur 19.4%, with 
 part of the nickel often replaced with iron or cobalt. 
 Out of 18 analyses the nickel ranges from 19 to 40%. 
 
 Gent/lite or Silicate of Nickel. Not crystallized, 
 occurring usually as incrustations. H. 3.4. G. 2.4. 
 Luster resinous. Color pale apple-green or yellowish* 
 Streak greenish white. Translucent to opaque. An 
 unimportant compound of nickel and silica, often 
 associated with chrome iron. 
 
 Annabergite or Nickel Ocher. In slender crystals; 
 also massive and disseminated through the gangue. 
 Soft. Color fine apple-green. Streak greenish white. 
 Fracture uneven or earthy. A compound of nickel 
 and arsenic. Unimportant. 
 
 Zaratite or Emerald Nickel. Incrusting, also mas- 
 sive and coraDact. H. 3,0 3.2. G, 2.6. Lustfv: 
 
ORES. 225 
 
 vitreous. Colo* 1 emerald-green. Streak pale green. 
 Translucent. Brittle. A carbonate of nickel. Unim- 
 portant. 
 
 (The last three minerals, with several others of 
 similar green color, include the green minerals found 
 in nickel ores, and which usually attract the attention 
 of the prospector from their bright color, resembling 
 the green carbonate of copper.) 
 
 COBALT Mispickel or Arsenical Pyrite. (Described 
 under iron ores). 
 
 ISmaltite, Smaltine or Cobalt Arsenide. Crystallized 
 and massive. H. 5.56.0. G. 6.4 7.2. Luster 
 metallic. Color tin-white, inclining when massive to 
 steel-gray, sometimes iridescent or tarnished. Streak 
 grayish black. .Fracture granular and uneven. 
 Brittle. Composition: cobalt 9.4, nickel 9.5, iron 
 9, and arsenic 72.1%. In some varieties the nickel is 
 absent and the cobalt runs up to 23% or over, replac- 
 ing the nickel and part of the iron. 
 
 Gobaiiite, Cobaltine or Cobalt Glance. Crystallized, 
 massive, granular and compact. H. 5.5. G. 6.0 
 6.3. Luster metallic. Color silver-white, inclined to 
 red; also steel-gray with a violet tinge, or grayish 
 black when containing much iron. Streak grayish 
 black. Fracture uneven and lamellar. Brittle. Com- 
 position : cobalt 35.5, arsenic 45.2, sulphur 19.3%. 
 The cobalt is sometimes largely replaced by the iron, 
 in which case the percentage may run down as low as 
 
 Erythrite, Cobalt Bloom or Red Cobalt. Crystal- 
 lized, also in globular and reniform shapes; also as 
 incrustations and powdery. H. 1.5 2.5. G. 2.9. 
 Luster pearly to vitreous; also dull and earthy. 
 Color crimson and peach-red, sometimes pearl to 
 greenish gray; red tints incline to blue. Streak a 
 little paler than the color; the dry powder deep 
 lavender-blue. Subtranslucent. Sectile. Composi- 
 tion: oxide of cobalt 37.55, arsenic acid 38.43, and 
 
226 PROSPECTING AND VALUING MINES. 
 
 water 24.02 %. The delicate peach-red of this min- 
 eral is very characteristic. 
 
 (The above are the chief cobalt ores. There are a 
 few others of less importance. Cobalt is a frequent 
 associate in nickel ores, and both nickel and cobalt 
 often occur in copper ores.) 
 
 ANTIMONY Stibnite, Antimony Sulphide, Gray Anti- 
 mony or Antimony Glance. Occurs crystallized or mas- 
 sive. When massive, not infrequently more or less 
 fibrous or radiated. H. 2.0. G. 4.5. Luster metal- 
 lic. Color and streak lead-gray, inclining to steel- 
 gray; liable to blackish tarnish. Fracture small sub- 
 conchoidaL Sectile. Composition: antimony 71.8, 
 sulphur 28,2%. Eesemblessorne manganese ores, but 
 is distinguished by being easily fusible. Furnishes 
 the bulk of the antimony of commerce. 
 
 (Native antimony and the oxides do not occur in 
 quantities to make them valuable as ores of the metal. ) 
 
 ARSENIC Realgar or Red Sulphide of Arsenic. 
 Crystallized or granular and compact. H. 1.5 2.0. 
 G. 3,5. Luster resinous. Color aurora-red or orange- 
 yellow. Streak similar. Translucent. Fracture un- 
 even. Composition: arsenic 70.1, sulphur 29.9%. 
 
 Orpimentor Yellow Sulphide of Arsenic. Crystallized 
 or massive. H. 1.5. G. 3.5. Luster pearly on the 
 faces of cleavage, elsewhere resinous. Color several 
 shades of lemon-yellow. Streak a little paler than the 
 color. Subtranslucent. Subsectile. Composition : 
 arsenic 61, sulphur 39%. 
 
 (The above minerals do not occur in large quanti- 
 ties. Artificially-made orpiment is used as a paint. 
 Commercial arsenic is usually a by-product from the 
 working of mispickel and the ores of nickel and 
 cobalt.) 
 
 BISMUTH Native. Crystallized, foliated or gran- 
 ular. H. 2.0.-- 2.5. G. 9.7. Luster metallic. 
 Streak and color silver-white, with a reddish hue; 
 subject to tarnish. Opaque. Sectile. Brittle when 
 
ORES. 
 
 cold, but somewhat malleable when heated. Very 
 fusible. 
 
 (Bismuth occurs in some dozen combinations, but 
 usually in small quantities with other compounds in 
 mineral veins. The native metal furnishes the bulk o.f 
 the commercial article.) 
 
 TITANIUM Entile or Titanium Oxide. Crystallized 
 or massive. H. 6.0 6.5. G. 4.2. Luster metallic- 
 adamantine. Color reddish brown, passing into red ; 
 sometimes yellowish, bluish, violet, black; rarely 
 grass-green. Streak pale brown. Subtransparent to 
 opaque. Fracture subconchoidal, uneven. Brittle. 
 Composition : titanium 61, oxygen 39%. 
 
 (Ilmenite, titanic iron, etc., are described with the 
 iron ores.) 
 
 TUNGSTEN Wolframite, Tung state of Iron. Crystal- 
 lized or massive. H. 5.0 5.5. G. 7.1 7.5. Lustersub- 
 raetallic. Color dark grayish or brownish black. 
 Streak dark reddish brown to black. Opaque. Com- 
 position : tungstic acid 76%, in combination with iron 
 and manganese in variable quantities. 
 
 (The tungstates of lead and lime are of minor im- 
 portance.) 
 
 CADMIUM Greenockite or Cadmium Sulphide. H. 
 3.0 3.5. G. 4.8. Luster adamantine. Color 
 honey-yellow, citron-yellow, orange-yellow, bronze- 
 yellow. Streak and powder between orange-yellow 
 and brick-red. Nearly transparent. Composition : 
 cadmium 77.7, sulphur 22.3%. 
 
 MOLYBDENUM Molybdenite or Molybdenum Sulphide. 
 ' "Usually foliated, massive, or in scales; also fine 
 granular. H. 1 1.5, being easily impressed by 
 the nail. G. 4.4 4.8. Luster metallic. Color pure 
 lead-gray. Streak similar to color, slightly inclined 
 to green. Opaque. Laminae very flexible, but not 
 elastic. Sectile, and almost malleable. Fine gray 
 mark on paper. Composition: molybdenum 59, sul- 
 phur 41%. Eesembles graphite, but is decomposed 
 b;* nitric acid. 
 
228 PROSPECTING AND VALUING MINES. 
 
 URANIUM Uraninite, Oxide of Uranium, Pitch- 
 blende. Usually massive and botryoidal; also in 
 grains. H. 5.5. G. 6.4 8. Luster submetallic to 
 greasy or pitchlike, and dull. Color grayish, green- 
 ish, brownish, velvet-black. Streak brownish black, 
 grayish, olive green, a little shining. Opaque. Frac- 
 ture conchoidal, uneven. 
 
 Autunite, Uranium Phosphate. H. 2.0 2.5. G. 
 3.0 3.2. Luster pearly to subadamantine. Color 
 citron -yellow to sulphur-yellow. Streak yellowish. 
 Translucent. 
 
 Torbernite, Uranium Phosphate, Copper Uraninite 
 H. 2.0 2.5. G. 3.5. Luster pearly to subadaman- 
 tine. Color emerald and grass-green, and sometimes 
 leek, apple and siskin-green. Streak somewhat paler 
 than the color. Translucent. Sectile. 
 
 (The above are usually associated with silver ores.) 
 
 VANADIUM Vanadinite or Vanadate of Lead. Usu- 
 ally in implanted globules or incrustations. H. 
 2.753.0. G. 6.67.2. Luster of surfaces of frac- 
 ture resinouSo Color light brownish yellow, straw- 
 yellow, reddish brown. Streak white or yellowish. 
 Subtranslucent to opaque. Fracture uneven Brittle, 
 
CHAPTER XIV. 
 USEFUL EARTHY MINERALS, ETC. 
 
 I. INSOLUBLE. 
 
 THE value of the deposits of the various minerals 
 grouped under this heading depends on the purity of 
 the article, the quantities in which it is found, the 
 cost of labor and the facilities of transportation, de- 
 fective conditions on any one of these points taking 
 the deposit out of the list of commercially available 
 propositions, as the market value per pound of most 
 of them is exceedingly low, and the number of locali- 
 ties in which they are found proportionally great; 
 while for some of them there is only a limited demand. 
 
 ASBESTOS is one of the few well-known minerals, 
 its white or greenish white or bluish fibrous appear- 
 ance being so characteristic as to be familiar to all 
 prospectors. In silkiness it may range from long 
 flexible fibers like flax to brittle earthy masses. It is 
 a widely diseminated mineral associated with rocks 
 which contain large quantities of hornblende or 
 augite, it being one of the products of the metamor- 
 phism or decomposition of these rocks, and is conse- 
 quently common among the hornblende-schists and 
 serpentines, which also produce chrome iron and soap- 
 stone, all three minerals usually occurring in the same 
 locality. 
 
 The great difficulty connected with the mining of 
 this substance is the large quantity of material which 
 
230 PROSPECTING AND VALUING MINES. 
 
 must be handled to secure any quantity of asbestos, 
 as it usually occurs in small threads, stringers, seams 
 or pockets, irregularly scattered through the contain- 
 ing rock, so that it must be worked in open quarries, 
 and the asbestos sorted by hand from the rock. It 
 varies greatly in character, from short earthy fibers 
 which are brittle and separate with difficulty, the 
 structure running across the seam and not parallel to 
 it, up to long fine silky threads of a pearly white color 
 very much resembling flax. The term "amianthus" 
 is applied to this last variety. The longer and more 
 flexible the fiber, the more valuable the mineral. 
 Asbestos is infusible, but the common notion that 
 articles made of it can be thrown into the fire and thus 
 cleansed of accumulated dirt, is erroneous, as at a red 
 heat the fibers lose their flexibility and become brittle. 
 
 It is used in the making of fireproof paints, roofing, 
 piston packing, valve packing, covering steam pipes 
 and boilers, fireproof cement, sheet and rolled mill- 
 board, flooring felt, textile fabrics, etc., being often 
 used in combination with hair felts and other sub- 
 stances. It derives its value for these purposes from 
 its indestructibilitj 7 in ordinary fires, and the resist- 
 ance it offers to the radiation of heat, a property which 
 it possesses in common with wool, cotton, feathers 
 and other substances which cannot be safely used in 
 the presence of high temperatures. For fireproof 
 paints the length of the fiber is not essential, but is a 
 desirable quality for packings and the covering of 
 steam pipes and boilers, while it is essential in all 
 textile fabrics. 
 
 Asbestos being associated with well-marked belts of 
 rock the prospector should familiarize himself with 
 the character and appearance of these rocks at any 
 locality where he may find asbestos, and having done 
 so, trace this belt along the mountain range, as it will 
 be comparatively useless to spend time on the rock 
 strata which lie either above or below it, excepting so 
 
USEFUL EARTHY MINERALS. 231 
 
 far as they may help him to locate the position of the 
 asbestos belt, where it is covered up by earth or debris^ 
 or not otherwise traceable. 
 
 ASPHALTUM. Amorphous or without crystalline 
 structure. G. 1 1.8, sometimes higher from im- 
 purities. Luster like that of black pitch. Color 
 brownish black and black. Odor bituminous. Melts 
 usually at about 194 to 212, and burns with a bright 
 flame. The more solid kinds graduate into mineral tar, 
 and through this there is a gradation to petroleum. 
 Asphaltum appears to be a residual deposit, derived 
 from the evaporation of petroleum products. In the 
 United States fche production is confined to the West- 
 ern States, the deposits (which are always found on 
 the surface or near it) occurring in California, Utah 
 and Colorado, being either fairly pure or mixed with 
 earthy matter. The principal source of foreign supply 
 is the island of Trinidad in the West Indies, where, at 
 a place called La Brea, there occurs an asphalt lake of 
 about 100 acres in extent, the product of which is 
 shipped to Europe and the Atlantic seaboard of the 
 United States. In Europe a limestone, naturally and 
 evenly impregnated with bitumen (or asphalt), is 
 largely used with good results, 
 
 It is used for many purposes where a surface imper- 
 meable to water is required, combined with toughness. 
 Natural asphalt rock, and asphaltum in combination 
 with other materials, are used in the surfacing of 
 streets and sidewalks, and the finishing of roofs. 
 Asphaltum makes a durable coating for water-pipes. 
 
 BARYTES. This mineral, also called "heavy spar," 
 because of its great weight, is a sulphate of barium. 
 Its specific gravity is about 4.5, while that of lime- 
 stone is only 2.5. It is an earthy mineral resembling 
 limestone, ranging in color from white through shades 
 of yellow, gray, red and brown to dark brown, accord- 
 ing to the amount of impurities present, but when 
 crystallized has a vitreous or glassy luster and a white 
 
232 PROSPECTING AND VALUING MINES. 
 
 streak when scratched. Some samples when rubbed 
 give off a fetid odor. It is not affected by acids, and 
 may thus be readily distinguished from the limestones 
 with which it may be associated, as well as by its 
 weight, which is much greater than any of the similar 
 minerals, such as gypsum and carbonate of magnesia. 
 
 It occurs in veins and beds associated with lime- 
 stones, sandstones and trap rocks, and not infrequently 
 forms the gangue, wholly or in part, of metallic veins, 
 especially those of lead. The mineral is widely dis- 
 tributed, occurring in beds in sandstones in Connecti- 
 cut, and at Isle Royal, Lake Superior; in beds in lime- 
 stone in Iowa and New York; and in limestone and 
 associated with lead ores in Missouri, North Carolina, 
 Tennessee and Virginia. On the northern shores of 
 Lake Superior veins occur in trap rocks. 
 
 Barytes is used very extensively in the arts, but 
 almost altogether for purposes of adulteration, for 
 which its leading use (about 90%) is in replacing to a 
 greater or less extent white lead in paint. The claim 
 is made that a mixture of one-third white lead, one- 
 third oxide of zinc and one-third ' 'floated " barytes 
 makes a better paint than pure white lead. It is also 
 employed as a "filling" for general purposes, in pulps 
 and in making putty and pottery. The value of 
 ground barytes being not much over one cent per 
 pound it is evident that only the purer deposits and 
 those best located for dressing and transportation can 
 be made available. It must be free from grains of 
 quartz, iron rust and other impurities, and of a good 
 white color. 
 
 BAUXITE. G. 2.5. Color whitish, grayish to yel- 
 low ocher, brown and red. Occurs in round concre- 
 tionary disseminated grains; also massive oolitic; 
 and earthy, clay-like. Bauxite occurs in the United 
 States in the Coosa Valley, Georgia and Alabama, in 
 clay beds along the line of an extensive fault in lime- 
 stone rocks, the beds having apparently accumulated 
 
USEFUL EARTH T MINERALS. 233 
 
 in depressions eroded along this fault, no eruptive 
 rocks being present; also in Arkansas, in regularly 
 stratified beds near the contact with eruptive rocks, 
 and in France as a residual deposit from the decay of 
 basaltic rocks. In Styria, a deposit 12 ft. thick occurs 
 at the junction of theTriassic and Jurassic formations. 
 The favorite associations appear to be limestone and 
 eruptive rocks. 
 
 From the large amount of alumina present in bauxite 
 it forms a valuable source of aluminum, and the purer 
 varieties are largely used in the production of that 
 metal, being known as "aluminum ore. " On the Con- 
 tinent of Europe the product of the quarries at Baux 
 in France, from which the mineral takes its name, is 
 also used as a flux in iron smelting. 
 
 It is difficult to give a concise description of this 
 valuable ore, but the following extracts from "Mineral 
 Industry," Vcjl. II., will probably be sufficient to call 
 attention to its chief peculiarities, and to suggest the 
 desirability of submitting suspected samples to 
 analysis: "Bauxite has few specially distinctive char- 
 acters except its usual pisolitic (pea-like) or concre- 
 tionary character, which perhaps accounts for its hav- 
 ing been so long overlooked, and for the comparatively 
 few localities where it is known to occur. The red 
 variety of bauxite was thought to be pisolitic iron ore 
 until its true character was shown by analysis. 
 
 "Bauxite is usually a concretionary or pisolitic min- 
 eral, though sometimes it is a hard, compact, homo- 
 geneous, fine-grained rock, commonly oolitic (made 
 up of round egg-like fragments), and sometimes an 
 earthy, clay-like material. It may therefore be hard, 
 or soft and friable, compact or porous, but the best 
 grades are hard and have a metallic ring. The con- 
 cretions vary in size from small peas to large bowlders, 
 which are cemented together by fine-grained hard 
 bauxite, bauxite clay or silicious material. In nearly 
 every case, however, the concretions or nodules are 
 
234 PROSPECTING AND VALUING MINES. 
 
 better mineral than the cementing material. The con- 
 cretions, also, are usually harder than the cementing 
 material, especially in the surface ores. 
 
 "On the surface, bauxite beds are generally marked 
 by hard, rough bowlders or loose nodules and pebbles 
 in the top soil. Below the surface, however, the nod- 
 ular and pebbly ores are often comparatively soft and 
 crumbly, and the compact oolitic and line-grained ores 
 -are sometimes a soft powder. 
 
 "Bauxite varies in color from almost pure white to 
 a deep red or black. It is also of cream and pearl- 
 white color, grayish, yellowish, amber, pinkish, 
 and speckled or mottled. . . . These colors often 
 shade into one another, sometimes suddenly and some- 
 times gradually, and it is seldom, if ever, that a bank 
 or deposit is wholly or uniform!}" of one color." 
 
 CLAYS are essentially silicates of alumina with 
 combined water (hydrated aluminum silicates), but 
 vary immensely in composition, not only from differ- 
 ences in the amount of silica and alumina present, but 
 also from the presence of impurities such as lime, 
 soda, potash, sand, magnesia and iron oxides which 
 affect the fusibility of the mass. It is these differences 
 which render "them suitable for different purposes, 
 For commercial use they may be classed as fire clays, 
 pottery and kaolin clays and brick clays. 
 
 Fire Clay. The presence of alkaline matter andiron 
 oxides tend to promote vitrification, and an excess of 
 alumina causes shrinkage in burning, so that a good fire 
 clay should consist practically of silica and alumina, 
 with the smallest amount possible of iron and alkali, it 
 being possible to counteract the contractibility or 
 shrinkage by the addition of quartz sand. The pres- 
 ence of an excess of alumina, however, renders the clay 
 more tenacious and plastic, but this is not essential in 
 a firebrick, though desirable in pottery clays. The 
 following table shows the relative composition of five 
 English fire clays and 14 American samples: 
 
USEFUL EARTHY MINERALS. 
 
 ANALYSES OF FIRE CLAYS. 
 
 235 
 
 
 
 a 
 
 
 | 
 
 jj 
 
 '55 
 
 
 
 | 
 
 
 
 <D 
 
 rt 
 
 "3 
 
 ca 
 
 a5 
 
 
 c/5 
 
 
 1 
 
 l d 
 
 ^ 
 
 1 
 
 1 
 
 English 
 
 66*80 
 
 21*70 
 
 6 66 
 
 2 60 
 
 1 29 
 
 32 
 
 49 
 
 American 
 
 48 38 
 
 38 81 
 
 15 29 
 
 1 19 
 
 68 
 
 06 
 
 02 
 
 
 
 
 
 
 
 
 
 The English examples are all from the older coal 
 measures and show as compared with more recent 
 clays a much less percentage of alumina; the American 
 samples are from the clay deposits of New Jersey, 
 Pennsylvania, Maryland, Illinois and Missouri. The 
 great essential in fire clays is that they should not con- 
 tain over 4% of impurities. 
 
 Brick Clays. From the most refractory all grades 
 occur to those which fuse or vitrify with the greatest 
 ease, and the adaptability of any deposit to a special 
 purpose is best determined by trial, it being, how- 
 ever, important, if the bed is to be worked on a large 
 scale, to ascertain if its composition is uniform 
 throughout. For brickmaking, the presence of lime 
 is a detriment, as if insufficiently ground the nodules 
 of lime, having been converted into quicklime while 
 burning, will afterward absorb water, expand in the 
 process and crack the brick. 
 
 Pottery Clays. Kaolin, which when pure is com- 
 posed of silica 46.3, alumina 39.8 and water 13.9%, is 
 the result of the decomposition of the feldspars in 
 granite rocks and porphyries, and furnishes the mate- 
 rial for the finer grades of chinaware and porcelain, 
 after a thorough preparation by washing and settling, 
 until the residue is an impalpable creamy paste. Very 
 large areas of these rocks, in some localities, have been 
 thus decomposed; but the presence of an excess of 
 iron oxides, which would color the finished product, 
 
236 PROSPECTING AND VALUING MINES. 
 
 or other impurities, render the bulk of them suitable 
 only for inferior grades of china ware. 
 
 CORUNDUM AND EMERY. "H. 9. G. 3 to 4.1. When 
 crystallized the luster is vitreous; color bine, red, 
 yellow, brown, gray and nearly white; streak un 
 colored. Transparent to translucent. Fracture con- 
 choidal, uneven. Exceedingly tough when com- 
 pact/' (Dana.) "These substances (corundum or 
 sapphire and emery), so nearly allied mineralog- 
 ically, are sharply distinguished in the trade. Min- 
 eralogically the former is a nearly pure alumina, while 
 the latter contains a large proportion, from 20 to 33%, 
 of iron oxide. The trade distinctions are somewhat 
 as follows : Emery is always black, while corundum 
 is of various colors, though more frequently gray and 
 never black. It is much harder than emery (taking 
 the sapphire at 100, Dana gives the abrasive power of 
 corundum at 62 and emery 46) and sharper, cuts 
 deeper and more rapidly, but is on the other hand 
 more brittle and consequently less durable/' (Gan- 
 nett.) These minerals are associated with crystalline 
 rocks such as granular limestone, gneiss, granite, mica 
 and chlorite schists. The emery of Asia Minor occurs 
 in granular limestone. All of the corundum used in 
 the United States is of domestic production, from 
 localities in the Appalachian range, extending from 
 Maine to Georgia, and from some western points as 
 Colorado and other States; but these latter are recent 
 developments, and as yet comparatively small pro- 
 ducers. Both corundum and emery are chiefly used 
 for grinding and polishing metals and other hard sub- 
 stances. 
 
 CRYOLITE. "H. 2.5. G. 2.95. Luster vitreous 
 or glassy ; slightly pearly on some faces of the crys- 
 tals. Colors now white, sometimes reddish or brown- 
 ish to brick-red and even black. Subtransparent; 
 immersion in water increases the transparency. 
 Brittle. Fusible in the flame of a candle. Occurs 
 
USEFUL EARTHY MINERALS. 237 
 
 sparingly in the crystal beds near Pike's Peak, Colo.; 
 but is a rare mineral in the United States. The prin- 
 cipal foreign locality is at Evigtok, in West Green- 
 land, where it constitutes a large bed or vein in 
 gneiss, and contains galena, zincblende, carbonate of 
 iron, iron pyrite, arsenical pyrite, fluorspar, tin ore 
 and colurntite, all of them frequently in tine crystals. 
 Taylor states that the cryolite is not white, except 
 within 10 to 15 ft. of the surface, and that below this 
 it becomes dark-colored and even black. The con- 
 tained ores and other minerals are most abundant near 
 the junction with the gneiss." 
 
 Cryolite is a compound of fluorine, alumina and 
 soda, and is used in the manufacture of the latter 
 article, and also in the production of aluminum (along 
 with bauxite), as well as an ingredient of a white, 
 porcelain-like glass. The main supply is at present 
 derived from the Greenland deposits. 
 
 FLUORSPAR. H. 4. Specific gravity 3.2. Streak 
 white. Fluorspar is a glassy-looking mineral, 
 nearly transparent when pale in color, which crystal- 
 lizes in square cubes. In color it has a wide range, 
 varying from white to yellow, green, blue, violet and 
 red, the commonest colors being white, pale green and 
 violet. The green varieties look very much like bottle 
 glass. When crystallized, the specimens are very 
 beautiful. It occurs in veins either by itself or as the 
 gangue of lead ores, and as beds or masses in lime- 
 stones, and is found in varying quantities in almost 
 every State of the Union, but not very frequently in 
 workable quantities. While apparently preferably 
 found associated with limestones, it also occurs in 
 veins in granite, gneiss, sandstones and slates, and as 
 a component of such rocks as rhyolite. Fluorspar is 
 used as a flux in some lead and copper smelting opera- 
 tions, in the manufacture of hydrofluoric acid for etch- 
 ing on glass and seals, as a glaze for pottery, and in the 
 production of aluminum. 
 
238 PROSPECTING AND VALUING MINES. 
 
 GRAPHITE OR PLUMBAGO (also often called "black- 
 lead"). A soft steel-gray to black mineral with a me- 
 tallic luster, and greasy feel; opaque; streak black and 
 shining; can be easily cut with a knife and soils the 
 fingers in handling. It is nearly pure carbon (con- 
 taining no lead as the common name might imply) and 
 resembles no other mineral except molybdenite, which 
 is lustrous lead-gray in color, with a streak inclining 
 to gray, and marks paper gray instead of the pure 
 black of graphite. Graphite occurs in veins, beds, 
 and disseminated in fine particles through some 
 schistose rocks, called graphitic schists. It is con- 
 fined to the older rocks, but is a widely disseminated 
 mineral. The veins are true fissures in gneissoid and 
 eruptive rocks. The veins produce the soft crystalline 
 and foliated forms, which are the purest and most 
 valuable. Graphite also occurs in beds, but is usually 
 more or less contaminated with impurities, and less 
 valuable commercially, the ores generally being of 
 such a character that purification is impossible. The 
 graphitic schists which are found in the same regions 
 as the veins are metamorphosed sandstones or slates 
 with foliated graphite very evenly distributed through 
 the mass in small flakes, giving a deep black color to 
 many of the slates. The localities where graphite 
 occurs in more or less quantity are very numerous, 
 but from this fact it is only those which produce the 
 very best kinds which have any commercial value. 
 
 American graphites come into competition with 
 those of Canada and Ceylon. In the latter island the 
 mineral occurs in veins of immense size and great 
 purity and is shipped without any preparation except 
 sizing. Graphite is used in the manufacture of cru- 
 cibles, stove-polish, lubricating compounds, foundr3 T - 
 faciugs, lead pencils, packing, paint and electrical 
 supplies, and also in electrotyping, etc. The first 
 three industries consume 75% of the production, the 
 consumption for pencils being only about 3%. 
 
USEFUL EARTHY MINERALS. 239 
 
 GYPSUM (SULPHATE OF LIME). H. 1.5 2.0. G. 
 2.3 for pure crystals. Luster shiny, pearly to 
 vitreous. Massive varieties often glistening, some- 
 times dull, earthy. Color usually white, sometimes 
 gray, flesh-red, honey-yellow, ocher-yellow, blue ; im- 
 pure varieties often black, brown, red or reddish brown. 
 Streak white. Transparent to opaque. In addition to 
 the above characters it may be mentioned that the crys- 
 tals are flat or tubular, and that the crystallized varie- 
 ties known as selenite split readily into thin trans- 
 parent sheets which are flexible, but not elastic; and 
 that when burned it forms plaster of paris, which 
 hardens promptly on being mixed with water, thus 
 differing from ordinary limestones, which also require 
 a much higher temperature in burning. 
 
 Gypsum in one or other of its forms is found in 
 large quantities in most of the States of the Union, in 
 connection with deposits of rock salt, being impreg- 
 nated with sulphur. The association with rock salt is 
 due to the fact that gypsum is a product of the evapora- 
 tion of sea water; as well as a product of lime-bearing 
 minerals under the action of decaying iron pyrite. 
 This latter action explains its presence in vein matter 
 and in claj r beds in a crystallized form. "The name 
 plaster of paris is in allusion to the large production 
 of that article at the gypsum beds of Montmartre near 
 Paris, which are mined on a very extensive scale. 
 "Selenite" is the term applied to the transparent crys- 
 tallized varieties; when silky and fibrous it is known 
 as "satin spar;" fine-grained varieties, delicately 
 tinted and suitable for the manufacture of ornaments, 
 are known as alabaster or onyx, the latter term being 
 erroneously employed. "The principal use to which 
 gypsum is devoted is an agricultural one. The 
 ground rock, or land plaster, is applied as a top dress- 
 ing to the soil; and although it does not enter directly 
 to any extent into the composition of plants, it has 
 still an extremely beneficial action upon plant life and 
 
240 PROSPECTING AND VALUING MINES. 
 
 growth, from the chemical changes which it induces 
 in the soil. Stucco, plaster of paris, or calcined gyp- 
 sum, is used for making cornices, friezes and other 
 forms of interior decorations, the finishing of walls, 
 etc. The finer grades are used in taking casts of 
 natural objects, making models, etc." 
 
 INFUSORIAL EARTH, tripoli, or mountain meal, consists 
 entirely when pure of the silicious skeletons of micro- 
 scopic vegetable organisms called diatoms, and in this 
 respect differs from chalk, which is similarly made up 
 of the infinitely minute shells of animal organisms 
 called foraminifera, but which are composed of lime 
 instead of silica, and consequently effervesce when 
 treated with acids, which is not the case with infuso- 
 rial earths. Deposits of infusorial earth often cover 
 many square miles and may be pure white and chalky 
 in appearance, like the deposit at Eed Mountain, north 
 of Virginia City, Nev., the origin of which must be 
 of comparatively recent date, geologically speaking, 
 as the writer has found in it remains of insects now 
 living in the neighborhood; the deposit at Santa 
 Fiora, Tuscany, consists of a grayish white, loose, 
 earthy meal, and similar material is also found in 
 Spain. Tripoli, or polishing slate, is a fragile, slaty 
 or thinly laminated variety, often much mixed with 
 impurities such as clay, magnesia, etc. Other consid- 
 erable deposits of differing character are found in 
 Nevada and California. Infusorial earth was at one 
 time largely used as an absorbent in the manufacture 
 of giant powder, but has given place to wood pulp of 
 late years, and is now used almost exclusively to give 
 body to soap, and as a polishing powder. The Ked 
 Mountain deposit is simply pulverized and put on the 
 market under the name of electro-silicon, being an ex- 
 ceptionally pure article of silica, showing less than 
 half of 1% of impurities. The demand is limited. 
 
 The harder, compact varieties, such as that found in 
 Newton County, Mo., are quarried and shaped into 
 water filters, which are of excellent quality. 
 
USEFUL EARTHY MINERALS. 241 
 
 LIMESTONE, in its various forms of ordinary stone or 
 marble is too well known to need further description, 
 and is found abundantly in all the States of the Union. 
 The production of quicklime for building purposes 
 amounts to over 60,000,000 bbl. of 200 Ib. each, 
 involving the quarrying of over 12,000,000 tons of rock. 
 This does not include that mined as flux for smelting 
 operations, or quarried as building stone. Provided 
 the lime is free from iron in appreciable quantities the 
 color is of little consequence to the burner, as it dis- 
 appears under the action of heat, and the product of 
 blue limestone and white marble are not to be distin- 
 guished from each other. The presence of iron is 
 objectionable, as it would rust in the mortar and when 
 leached out by rain would stain the building. Mag- 
 nesian limestones, or dolomite, have usually tinges of 
 yellow, buff or drab, instead of tending to blue tints, 
 and are used in the manufacture of hydraulic or quick 
 setting cements. The value of marble depends largely 
 on the fineness of the grain and the purity, beauty or 
 peculiarity of the coloring, but with all the good qual- 
 ities at a maximum the deposit may be valueless if 
 unfortunately situated as regards cheap transporta- 
 tion. 
 
 It is desirable that limestones used as flux for iron 
 smelting should be free from phosphorus, just as the 
 same quality is desirable in the fuel, because nearly 
 the whole of the phosphorus present, both in the ore, 
 fuel and flux, will be concentrated in the pig iron 
 produced, decreasing its value materially and render- 
 ing it totally unfitted for many purposes, especially 
 the production of Bessemer steel, which requires a 
 practical absence of phosphorus in all the material 
 which goes into the blast furnace. 
 
 Impurities in the limestone used for making quick- 
 lime, especially silica and alumina, have a tendency to 
 vitrify, or melt into more or less glassy particles, dur- 
 ing the process of burning, and the product does not 
 
PROSPECTING AND VALUING MINES. 
 
 slake into as smooth a paste as that produced from 
 purer rocks, but these "poor" limes are said to make 
 a mortar which is able to resist the destructive action 
 of atmospheric agencies better than the "rich" ones, 
 being apparently less soluble in rain water. 
 
 Limestone is so abundant a material in nature that 
 we need in this place call attention only to one par- 
 ticular variety, used for lithographic purposes. There 
 is no absolute chemical composition, analyses showing 
 a varying amount of carbonate of magnesium (2.50 to 
 17.32%) along with the carbonate of lime and various 
 small quantities of other substances. The stones in use 
 are usually shades of drab or gray, and they must be 
 absolutely of uniform composition throughout, some- 
 what porous and soft enough to work easily under the 
 engraver's tool, but tough enough to bear consider- 
 able pressure in the printing press. Such a stone will 
 be very fine-grained and break with a shell-like (con- 
 choidal) fracture. Only actual trial will prove the 
 suitability of a particular stone,but localities which can 
 produce good stones of large size, say 40 by 60 in., are 
 extremely valuable. 
 
 MAGNESITE is a carbonate of magnesium, white in 
 color when pure, but shading into brown when iron is 
 present. It is moderately hard, tough, and breaks 
 with flat conchoidal surfaces, and is somewhat heavier 
 than quartz. It looks something like limestone, but 
 is only feebly acted on by cold acids, though when 
 powdered it dissolves readib T in warm muriatic acid 
 with effervescence. It is usually found in connection 
 with serpentine rocks, talcose schists, and consequently 
 with soapstone and asbestos, all of which are magne- 
 sian products. The ore is used chiefly in the manu- 
 facture of paper from wood pulp, and as a refractory 
 lining for furnaces using the basic process for steel 
 making. 
 
 MICA ranges in color from white and very pale 
 greenish and brownish shades through dark brown to 
 
USEFUL EARTHY MINERALS. 243 
 
 black. It splits easily into very thin sheets, some- 
 times as many as 160 to the inch, which in the paler 
 colored varieties are transparent, but only partially so 
 in the dark ones. These thin plates or larninse are 
 flexible and not easily fusible, and in this respect 
 differ from crystallized gypsum or sulphate of lime, 
 which while separating into very thin flakes is not 
 flexible, and when heated crumbles into a fine powder, 
 the plaster of paris of commerce. The two are often 
 mistaken for each other and confounded under the 
 common name of "isinglass," which is really fish glue 
 or a compound prepared from gelatine, and an organic 
 product. When scratched or crushed the result is a 
 whitish powder even in the case of the dark varieties. 
 Mica is a common constituent of granite, 
 gneissic and schistose rocks, and is found in many 
 localities in crystals of larger .size than those usually 
 forming an essential ingredient of the rocks 
 mentioned. Such crystals have been reported from 
 North Carolina and the other South Atlantic States; 
 Maine, New Hampshire, Pennsylvania, South Dakota, 
 New Mexico, Wyoming, California and elsewhere. It 
 has been found in almost all the Pacific States but not 
 in workable quantities of good quality. South Dakota 
 has produced plates 12 by 18 in. in size from a vein 
 which is said to be 14 ft. wide, and to consist of a 
 central mass of feldspar and porphyry, with a casing 
 of mica, which varies in width from 3 to 4 ft., on each 
 side. The country rock is granite. Clear, transpar- 
 ent and tough mica plates are used in various ways, 
 the principal utilization being for stove and furnace 
 doors. A small amount of specially fine mica is used 
 for compass plates. The inferior varieties not suitable 
 for the above uses are largely used as an insulating 
 substance in electrical machinery; while the scrap 
 trimmings of the better kinds, as well as large quanti- 
 ties of the inferior sorts, are pulverized and used as an 
 absorbent for nitro-glycerine explosives, and also in 
 
244 PROSPECTING AND VALUING MINES. 
 
 the composition of lubricating compounds; as well as 
 for various ornamental purposes in the arts. 
 
 Mica only in plates of large size and good color 
 has any high commercial value. For such plates 
 the price increases more rapidly than the size 
 of the plates, which may be said to range in value 
 from 25c. to $5 per lb., with occasionally higher 
 prices for exceptionally large and good plates. The 
 industry in the United States fluctuates very greatly 
 both in the quantity produced and its average value, 
 chiefly owing to the uncertain character of the 
 deposits, which may suddenly become worthless. 
 
 From the peculiar conditions of the mica trade 
 it is evident that good, large plates can bear somewhat 
 high rates of freight, and can be worked in out of the 
 way localities, but if of only small or moderate size, 
 the necessity for cheap labor in dressing and cutting 
 the blocks, and freight charges, may render the 
 deposit valueless, especially if the cost of mining is 
 high, as large quantities of material must often be 
 moved to secure a few pounds of plates, the conditions 
 being very much the same as surround mining for 
 asbestos. 
 
 The scales of yellow mica, found in the streams of 
 granite and schistose mountains, are frequently mis- 
 taken for gold by the uninitiated, but can easily be 
 distinguished by their softness and light weight, as 
 well as by their loss of the yellow color when ground 
 to powder. 
 
 OZOKERITE. Like wax or spermaceti in appearance 
 and consistency. G. 0.85 0.90. Colorless to white 
 when pure; often leek-green, yellowish, brownish 
 yellow or brown; and when brown, sometimes 
 green by transmitted light through thin shavings. 
 Greasy to the touch. Melts at 133 to 146 F. Burns 
 readily in thin shavings or at the angles of specimens, 
 when ignited with a match. (Dana in part.) Ozoker- 
 ite, or native paraffin, is not a common product in 
 
USEFUL EARTHY MINERALS, 245 
 
 nature. It occurs in beds of coal or associated with 
 bituminous substances. In the United States it is 
 found in Utah. Abroad it occurs at Slanik, Moldavia, 
 beneath a bed of bituminous clay shale; in masses of 
 sometimes 80 to 100 lb., at the foot of the Car- 
 pathians, not far from beds of coal and salt; that of 
 Boryslan in a bituminous clay, associated with calcif- 
 erous beds in masses. It is also reported from the 
 Carpathian sandstones in Transylvania and other less 
 important localities. Ozokerite, mineral wax or 
 native paraffin is used in the manufacture of candles 
 and heavy lubricants, very extensively as an insulator 
 for electrical wiring, and generally as a substitute for 
 most of the uses of beeswax. 
 
 PUMICE STONE is an exceedingly porous, spongy- 
 looking lava in which the air bubbles are so numerous 
 that it will float on water, and varies in color from 
 dirty white to pearly gray. It, aside from its use as a 
 toilet article, is chiefly employed in polishing marble. 
 The bulk of the article is imported in the lump for 
 use in the Eastern States from Italy, where it is found 
 abundantly on Mount Vesuvius; while most of that 
 used on the Pacific Coast is produced in California 
 from deposits at Lake Honda, a few miles south of San 
 Francisco. Other deposits of good quality also occur 
 in California, near Mono Lake, which is the crater of 
 an extinct volcano, and at Little Owens Lake and 
 other localities in Inyo County. The annual con- 
 sumption is not large and the price low, so that cheap 
 transportation is essential. 
 
 QUARTZ. H. 7.0. G. 2.6. Luster vitreous or glassy 
 to nearly dull. Colorless when pure; often various 
 shades of yellow, red, brown, green, blue, purple and 
 black, Streak white of pure varieties; when impure 
 often similar in color, but paler. Transparent to 
 opaque. Quartz takes many forms, and is one of 
 the commonest minerals, but is chiefly used commer- 
 cially in the condition of sand> sandstone or quartzite. 
 
246 PROSPECTING AND VALUING MINES. 
 
 Beds of sand and sandstone are common everywhere, 
 but they are not all available for the same class of 
 work on account of the associated impurities, and 
 their value for any particular purpose can only be 
 thoroughly ascertained by working tests. 
 
 The finest kinds of transparent quartz, known as 
 " rock-crystal," are or rather were extensively used in 
 the manufacture of spectacle glasses, but the improve- 
 ments in glass making have diminished this applica- 
 tion. Similar quartz is used extensively in glass and 
 pottery making, and as a grinding and polishing 
 powder. Ground quartz is also used in the manufac- 
 ture of sandpaper. In addition to these a peculiar 
 variety of sandstone called "ganister" is largely used 
 in the lining of vessels used in the manufacture of 
 steel on account of its excessively refractory character. 
 In England the ganister preferred for lining is a 
 peculiar silicious deposit found under a thin coal seam 
 near Sheffield, of almost conchoidal fracture, thereby 
 differing from ordinary sandstone, and containing a few 
 tenths per cent., or sometimes a little more, of lime, 
 and the same amount of alumina, with small quantities 
 of iron oxide and alkalies, the rest being silica; 
 analagous substances are found, however, in other 
 localities in the northern coal tields. Beds of such 
 quartz in the vicinity of steel works are valuable. 
 
 For mortar making, river sand is preferable, as salt 
 from sea sands will certainly make its appearance on 
 brickwork where it is used, spoiling the looks of the 
 building as well as being objectionable on account of 
 absorbing moisture; it is also sharper, with less 
 rounded angles, as in rapid streams much of it is car- 
 ried down suspended in the water and the angles 
 scarcely suffer any abrasion. 
 
 STRONTIA, STRONTIANITE, ETC. The metal strontium 
 occurs as a carbonate, under the name of strontia- 
 nite, and as a sulphate, under the name celestite. When 
 crystallized strontianite has a hardness of 3.5 4, and 
 
USEFUL EARTHY MINERALS. 347 
 
 a specific gravity of 3.65, with a vitreous or resinous 
 luster, and white streak. In color it is pale asparagus- 
 green or apple-green ; white, gray, yellow and yellow- 
 ish brown. Transparent to translucent. (Dana.) It 
 occurs in the United States in granular and columnar 
 masses in hydraulic limestones at Schoharie, N. Y. ; 
 and at Muscalonge Lake in the same State, a 
 massive and fibrous variety of a white or greenish 
 white color is found associated with fluorspar. In 
 Scotland it occurs in veins traversing gneiss, along 
 with galena and bante (barytes). (Dana.) 
 
 Celestite has a hardness of 3 3.5 and sp. gr. of 
 3.95, being somewhat softer and heavier than stron- 
 tianite. The luster is vitreous inclining to pearly 
 when crystallized, and the streak white. The color 
 white, often bluish (from which it takes its name) and 
 sometimes reddish. More or less transparent. (Dana.) 
 Celestite is usually associated with limestone or sand- 
 stone, and occurs also in beds of gypsum, rock salt 
 and clay. (Dana.) In the United States it is reported 
 from the limestones about Lake Huron ; from New 
 York and Pennsylvania, and also from Green orStron- 
 tian Island, Lake Erie. 
 
 Nitrate of strontia is used to a considerable extent by 
 the makers of fireworks for the production of red fire. 
 The use of strontia has also been proposed in the treat- 
 ment of beet sugar, and in the manufacture of tuyeres 
 for blast furnaces. Sicily furnishes the bulk of the 
 mineral at the present time, but little search for it 
 having been made in the United States on account of 
 the small demand. 
 
 SULPHUR cannot be mistaken for any other mineral, 
 its brilliant yellow color, and characteristic odor on 
 burning, separating it instantly from all others- 
 "Wherever found it appears to be associated with vol- 
 canic action and hot springs, having been deposited 
 by such agencies in vast beds both in Europe and 
 America. In boring for petroleum near Lake Charles, 
 
248 PROSPECTING AND VALUING MINES. 
 
 Calcasieu Parish, Louisiana, "at a depth of 423 ft. the 
 drill passed through 100 ft. of pure sulphur and 148 
 ft. of gypsum mixed with sulphur, the former mineral 
 being a common associate of sulphur deposits, by the 
 conversion of ordinarj 7 limestone into the sulphate 
 through the action of sulphuric acid. In Nevada, the 
 beds near Silver Peak are traversed by seams of alum, 
 formed in a similar way by the decomposition of 
 aluminous or clay-forming rocks. In California, at 
 the Sulphur Banks in Lake County, the deposits are 
 associated with cinnabar or mercury and borax. In 
 Southern Utah the occurrence is evidently in what was 
 formerly a crater of a volcano, about three miles from 
 Fort Cove Creek. The crater forms a small basin sur- 
 rounded by low hills with a narrow ravine opening 
 into the plain probably a breach in the old crater 
 wails which consist mainly of andesite with some 
 pale whitish trachyte (both porphyries) with obsidian 
 splinters scattered over the surface. As far as explored 
 the sulphur beds extend over an area of at least 1,800 
 by 1,000 ft. across. The sulphur shows upon the sur- 
 face over part of the basin, but is mostly covered with 
 sand, or rather the disintegrated andesite of the sur- 
 rounding hills. A curved cut through the western 
 end of the deposit exposes a vertical wall of rich yellow 
 sulphur 34 ft. high, from which in many places, as 
 well as in other prospect-holes, gases escape, together 
 with water holding various salts in solution." "At the 
 Mammoth claim in the same neighborhood, the slates 
 and limestones are impregnated with sulphur, gypsum 
 being also found as a product of altered limestones; 
 while at the Sulphur King claim the andesifes are 
 similarly saturated." 
 
 The depositio'n of sulphur is constantly going on at 
 volcanic vents and many hot springs. "Mount Purace, 
 in Colombia, wears a cap of sulphur (derived from its 
 own crater) which accumulates at the rate of 2 ft. per 
 annum its superficial area amounting to 1,435 sq, 
 
USEFUL EARTHY MINERALS. 249 
 
 yards;" and the sulphur forming in the crater of Popo- 
 catapetl, in Mexico, is regularly worked by the Indians. 
 The salfatara of Bahara Saphinque on the Red Sea is 
 said to yield 600 tons of sulphur annually. American 
 sulphur comes into sharp competition with that pro- 
 duced by the Sicilian deposits (which have been worked 
 to a depth of over 300 ft. and turn out annually 
 400,000 tons of clean sulphur), and can consequently 
 only be profitably exploited under the most favorable 
 conditions of labor and transportation aided by local 
 demand, which it fostered by the high rates of freight 
 on sulphuric acid on account of its dangerous char- 
 acter. Native sulphur is also met in the market by 
 acid produced from iron and copper pyrites, which are 
 now mined in enormous quantities for that purpose, 
 as the contained metals furnish a valuable by-product. 
 
 The larger portion of the entire product of 
 sulphur is used in the manufacture of sulphuric acid, 
 the consumption of which in manufactures is extend- 
 ing daily. Outside of this it is employed in the pro- 
 duction of vulcanized rubber goods; in the manufac- 
 ture of "bluestone, " or sulphate of copper, which is 
 largely used in metallurgical operations; as a preven- 
 tative of and cure for mildew on plants by horticul- 
 turists, and many minor uses. 
 
 TALC AND SOAPSTONE. H. 1 1.5. G. 2.65. Luster 
 pearly. Color apple-green to white, or silvery white; 
 also greenish gray and dark green; brownish to 
 blackish green and reddish when impure. Streak 
 usually white; of dark-colored varieties, lighter 
 than the color. Easily cut with a knife. Thin 
 sheets flexible, but not elastic. Feels greasy. (Dana.) 
 The foregoing description is of the purer and softer 
 varieties, from which the harder kinds are separated as 
 "soapstone, " to the best kinds of which the term 
 "French chalk" is applied. The mineral is soft enough 
 to leave a whitish mark on cloth, and is used by tailors 
 in drawing their patterns. The various forms of talc are 
 
250 PROSPECTING AND VALUING MINES. 
 
 of very common occurrence; and steatite or soapstone 
 forms extensive beds in some regions, being often 
 associated with serpentines, chloritic or talcose schists, 
 in which latter rock thin flakes of talc take the place 
 of mica, and impart to it a certain greasy feel, which 
 is characteristic of the entire series of minerals asso- 
 ciated under the name, which is often applied by miners 
 and prospectors to any soft white earthy substance in 
 the gouge of veins, whether greasy or not. Talc is 
 used extensively in soap making, and in dressing fine 
 sheep-skins, leather, gloves, etc. The finer, soft, foli- 
 ated variety is used in the manufacture of paper, and 
 small quantities enter into the composition of some 
 lubricating compounds. "Soapstone," OD account of 
 its refractory nature in the presence of intense heat, 
 and the facility with which it can be sawn into bricks, 
 slabs or any desirable shape, is extensively used as 
 a lining for stoves, furnaces, etc. It can be easily 
 turned in a lathe, and the writer has seen on the 
 Mexican border a very ancient tuyere for a black- 
 smith's forge made out of such material. It was 
 found in grading for a ditch, and from the size of the 
 trees growing over the spot must have been buried for 
 at least 100 years, and may possibly be a relic of the 
 early missionary days of California. 
 
 II. SOLUBLE MINERALS. 
 
 With the exception of common salt, which is of gen- 
 eral distribution, and Stassfnrt salt and its associ- 
 ates, the balance of the useful minerals of t'his group 
 all occur in arid regions, where the climatic con- 
 ditions favor the evaporation of the water which dis- 
 solves the various salts and holds them in suspension. 
 Many of them are found in foreign countries where 
 the price of labor is extraordinarily low, and from 
 which ocean carriage is remarkably cheap, so that the 
 products of the United States being found far inland, 
 in thinly populated regions and often in consequence 
 
USEFUL EARTHY MINERALS. 251 
 
 far from convenient lines of transportation, can with 
 difficulty compete with the imported articles. The 
 efflorescences or crusts of borate of soda, carbonate of 
 soda and salt greatly resemble each other, but can be 
 separated by the tests given in the description of these 
 minerals, the presence of carbonate of soda being indi- 
 cated by effervescence if citric acid be added to a solu- 
 tion of the incrustation,, The compact massive 
 deposits found underlying these incrustations may 
 also be tested in the same manner, and while under 
 existing conditions of trade and transportation they 
 may not be available for other than local consumption, 
 they may possibly supply a mineral which will render 
 others available, just as cheap soda is necessary to 
 make quartz sand valuable for the production of glass. 
 
 BORAX. H. 2 2.5. G. 1.7. Luster vitreous to 
 resinous, sometimes earthy. Color white, sometimes 
 grayish, bluish or greenish. Streak white. Trans- 
 lucent to opaque. Bather brittle. Taste sweetish- 
 alkaline. Imparts a clear green color to the flame. 
 Boiling water dissolves double its weight of borax. 
 (Dana.) 
 
 Borate of Lime, Ulexite or Hayesine. H. 1.0. 
 G. 1.65. Color white. Tasteless. Loose in texture, 
 fibrous and silky, usually in rounded masses. 
 
 Crystallized borax (or borate of soda) is found 
 in the mud of certain lakes both in California 
 and Asia, but the great bulk is produced from the 
 borate marshes of Nevada and California, of which the 
 general character is well described in the Geological 
 Survey reports of 1883. "The borate fields are situ- 
 ated in the extensive salines known as Teel's marsh, 
 Bhodes's marsh, the Columbus marsh and Fish Lake 
 Valley, all in the southeasterly part of Esmeralda 
 County. These salines consist of oval-shaped alkali 
 flats occupying the centers of immense basins, and 
 cover from 10,000 to 20,000 acres each. These basins 
 are surrounded for the most part by a broad margin 
 
262 PROSPECTING AND VALUING MINES, 
 
 of sage plains which rise gradually to the base of the 
 hills and mountains which inclose them on every 
 hand. They have no outlets, and, receiving the 
 drainage of the country around, retain everything 
 brought into them, including the borates and salts of 
 various kinds. From midsummer till late in the 
 spring, when the snow commences to melt on the 
 mountains, these saliniferous lands are, as a general 
 thing, apt to be dry, only shallow lakes occupying 
 sometimes their points of greatest depression. At 
 other seasons of the year portions of them are covered 
 with water to the depth of a foot or two. Heavy 
 rains, though these seldom occur in these regions, con- 
 vert these alkali flats into beds of tenacious mud, even 
 a slight shower rendering their passage by teams dif- 
 ficult for the time being. Water can be obtained on 
 these salines almost anywhere by digging from 2 or 3 
 to 10 or 15 ft. below the surface. It is general!}' 
 brackish, however, often so much so as to be scarcel^ 
 fit for drinking. By digging to much greater depths 
 good water is obtained a short distance back from the 
 edge of the marsh. Over large sections of these flats 
 exist deposits of common salt, carbonate of soda, and 
 borax. This latter mineral does not, however, occur 
 here, as at Clear Lake in California, in the shape of 
 compact, semiopaque crystals imbedded in mud, but 
 generally in the form of borate of lime or soda. The 
 former is found at many spots imbedded in these 
 marshes from 1 to 4 ft. below the surface.* It crystal- 
 lizes in long silky fibers which gather into balls from 
 an eighth of an inch to 2 or 3 in. in diameter. These 
 globular masses have the luster of white satin, and 
 when dug up readily separate from the inclosing 
 earth. The borate of soda mixed with sand and other 
 impurities accumulates on the surface in the shape of 
 a dark-colored incrustation an inch or two thick. 
 This crust when dry, being hard and brittle, can be 
 easily detached from the moister ground beneath and 
 broken into fragments/' 
 
USEFUL EARTHY MINERALS. 253 
 
 While Nevada and California are the only produc- 
 ing States in North America, there are extensive 
 deposits in Europe, India, Peru and Asiatic Turkey, 
 and competition has reduced the price from the old 
 standard of 25 or 30 c. per Ib. to a very low figure, 
 the reduction having, however, opened up new avenues 
 of use. 
 
 The leading uses of borax are in welding (for which 
 the greater part is consumed in iron and steel manu- 
 facture); in refining metals as a crucible flux; in 
 enamelling; by packers, in preserving meat; and as a 
 detergent for household purposes. 
 
 CARBONATE OF SODA OR TRONA. H. 2.5 3.0, G. 
 2.10. Luster vitreous, glistening. Color gray or 
 yellowish white. Translucent. Taste alkaline. Not 
 altered by exposure to a dry atmosphere. (Dana.) 
 Soluble in water and effervesces with acids. Trona 
 is another of the minerals occurring as the result of 
 the evaporation of water in dry inland basins without 
 drainage outlets. The following description of one 
 such deposit will convey a good idea of them all : 
 
 "This mineral abounds throughout most parts of 
 the Great Basin, the extensive alkali flats which form 
 a feature of that region constituting the principal sites 
 of these deposits, which occur usually in the form of 
 an efflorescence an inch or two thick on the surface, 
 but sometimes in strata a foot or more thick imbedded 
 in the earth, and separated from each other by thin 
 seams of clay. When found in the form of a thin 
 incrustation on the surface it is never pure, being 
 always admixed with salt, borax, lime, magnesia and 
 other minerals. The heavier deposits are compara- 
 tively free from foreign matter, carrying generally 
 about 90% carbonate of soda. One of the most re- 
 markable repositories of this mineral known consists 
 of a circular basin, the bed of a former lake, situated 
 on the southerly margin of the Forty-mile desert, 
 Churchill County, Nev. This basin, which covers 
 
254 PROSPECTING AND VALUING MINES. 
 
 an area of 10 or 12 acres, is depressed 60 ft. below the 
 common level of the country adjacent. Its bottom, 
 usually dry, though in wet seasons oovered with a few 
 inches of water, is composed of a compact mass of the 
 carbonate of soda so hard that it ,has to be broken out 
 with crowbars, and so pure that it can for many pur- 
 poses be used to advantage in its natural state. This 
 substance occurs here in layers about 1 foot thick, 
 separated from each other by thin seams of clay. 
 Large quantities of the crude material are extracted 
 every year. " This deposit has been worked over an 
 area of several acres to a depth of 10 or 12 ft. without 
 showing any signs of exhaustion. A portion of the 
 product from the above locality is used in the working 
 of the neighboring silver ores, but the greater portion 
 is refined and sold for other purposes, soda being very 
 extensively employed both in the arts and manufac- 
 tures. 
 
 NITRATE OF POTASH, NITER OR SALTPETER. H. 2,0. 
 G, .1.9. Luster vitreous. Streak and color white. 
 Subtransparent. Brittle. Taste saline and cooling. 
 Deflagrates vividly on burning coals, and detonates 
 when mixed with combustible substances. (Dana.) 
 Dissolves easily in water and is not altered by expo- 
 sure. Colors the flame violet when burned. It occurs 
 as an efflorescence on the surface or in the surface 
 stratum of the soil in many parts of the world, but 
 especially to a great extent in the valley of the Ganges 
 and other parts of India, as well as in Spain, Egypt 
 and Persia. It is also obtained in a semi-artificial 
 manner in nitaries or saltpeter plantations. These 
 consist of heaps of decomposing animal matter, mixed 
 with lime, ashes, road scrapings and other rubbish, 
 covered over from rain, and from time to time damped 
 with the runnings from stables and other urine. Such 
 heaps develop within them small proportions of the 
 salt, and other nitrates, and are in effect artificial 
 imitations of the saltpeter-bearing soil of India. 
 
USEFUL EARTHY MINERALS. 255 
 
 Niter requires for its formation dry air and long 
 periods without rain, and is produced most abun- 
 dantly during hot weather succeeding rain. The 
 potash comes mainly from the debris of feldspathic 
 rocks in the soil. (See chapter on rocks for the per- 
 centages of potash in various kinds of rocks.) It also 
 forms abundantly on the walls of caverns and in the 
 loose earth floors of the same, which abound in the 
 limestones of the Mississippi Valley in Kentucky and 
 Tennessee. It is now prepared artificially from Chili- 
 saltpeter and the German chloride of potash, by 
 mutual decomposition, producing chloride of sodium 
 or common salt and nitrate of potash, or saltpeter/and 
 this product has largely supplanted the native article, 
 being a much superior material. 
 
 India furnishes the bulk of the imported niter. 
 
 NITRATE OF SODA OR CHILP-SALTPETER. JL 1.5 
 2.0. G. 2.0 2.3. Luster vitreous. Color white; 
 also reddish brown, gray and lemon-yellow. Trans- 
 parent. Bather sectile instead of brittle. Taste cool- 
 ing. Deflagrates with less violence than niter, and 
 colors the flame yellow ; also absorbs water on ex- 
 posure to moisture and deliquesces. (Dana.) 
 
 Chili saltpeter occurs on exceedingly dry and arid 
 plains in North and South America chiefly. In South 
 America in the district of Tarapaca, Northern Chili, 
 the dry pampas for 40 leagues, at a height of 8,300 ft. 
 above the sea, is covered with beds of this salt several 
 feet in thickness, along with gypsum, common salt and 
 glauber salt, with remains of recent shells indicating 
 the former presence of the sea. The arid plains of the 
 Great American basin present almost identical condi- 
 tions as regards altitude, climate aud rainfall (on the 
 Nevada deserts only about 4 in. annually), and as 
 might have been expected, this mineral is found on 
 the 40-mile desert near Lovelock's Station, crystallized 
 in the crevices of rocks and imbedded in the earth 
 from 2 to 30 in. below the surface. Its occurrence is 
 
256 PROSPECTING AND VALUING MINES. 
 
 also reported in a similar country near Calico, San 
 Bernardino County, Cal. ; and in the southern part of 
 New Mexico, near tbe Chihuahua line, the mineral is 
 said to be deposited by springs in considerable quan- 
 tity. 
 
 Nitrate of soda is used extensiveb r in the pro- 
 duction of nitric acid and saltpeter or nitrate of 
 potash, the latter product entering into the composi- 
 tion of gunpowder. 
 
 SALT is sufficiently well known to be distinguished 
 from other similar minerals, when in comparatively 
 pure condition, by its taste alone. Rock salt occurs as 
 immense beds formed by the evaporation of sea water, 
 associated with deposits of gypsum and other marine 
 products. Percolating waters dissolve these accumu- 
 lations and supply the brines for the salt wells of 
 Michigan, New York and other Eastern States, which 
 vary in depth from a few up to 1,000 ft., the average 
 depth in Michigan being 882 ft. ; in New York, 322; 
 Ohio, 932; Pennsylvania, 883; and Virginia, 1,042 ft. 
 The shallowest wells are in Utah, Texas and Kansas. 
 Some brines are obtained not from beds of pure rock 
 salt, but from strata of salt-bearing rocks such as 
 sandstone, shale, etc. The brines from these wells 
 are evaporated by artificial heat. In California, solar 
 heat is extensively used in the neighborhood of San 
 Francisco in the evaporation of sea water; while in 
 Nevada salt is abundant in all the interior basins 
 either as beds of rock salt, as incrustations on the sur- 
 face, which are renewed as often as they are removed, 
 and that so rapidly as to afford several crops annually, 
 or as massive deposits, covered with slight deposits of 
 sand or clay. 
 
 SULPHATE OF SODA. H. 2.03.0. G. 2.6. Luster 
 vitreous. Color white to brown. Translucent. 
 Wholly soluble in water. The occurrence is very 
 similar to that of carbonate of soda just described, the 
 material being found extensively in lakes and beds in 
 
USEFUL EARTHY MINERALS. 257 
 
 the States of Wyoming and Colorado, and in smaller 
 quantities in New Mexico. Well known localities are 
 the lake near Independence Rock and the lake seven 
 miles from St. Mary's Station, both in the Sweetwater 
 valley; and Burclsall's Lake near Morrison in Colo- 
 rado. While outwardly appearing much the same, 
 analysis develops the occurrence in the deposits of car- 
 bonate of soda, and common salt, in varying propor- 
 tions, as well as various impurities such an silica, lime 
 and magnesia. Available in the manufacture of soda, 
 glass and gunpowder. 
 
 III. LIQUID. 
 
 PETROLEUM. Crude petroleum varies considerably 
 in composition and density, the latter varying from 
 0.60 to 0.80, forming the so-called light and heavy 
 oils. The light oils give proportionately more illumi- 
 nating oil (kerosene); the heavj 7 , more lubricating oil 
 and residue. It is a hydrocarbon, standing inter- 
 mediate in the series ranging between the asphaltum 
 group of minerals at one end to the lightest naphthas 
 at the other. Its exact origin is in dispute, but is 
 probably the decay of animal and vegetable substances 
 under peculiar conditions. It is usually dark green- 
 ish brown in color, and is easily recognizable by its 
 peculiar fetid odor. Its inflammability varies and is not 
 always a reliable test, as some specimens (of the heavy 
 or impure varieties) do not ignite very readily. In the 
 United States the light oils are found mainly in the 
 eastern fields; from Ohio westward the oils are usually 
 of the heavy variety. It occurs in porous sedimentary 
 rocks of all kinds, as in sandstones, shales and some 
 limestones; and in point of geologic age all the way 
 from the Silurian to the most recent. At the surface 
 it appears as springs, pools and as a scum floating upon 
 the water. The surface prospecting consists merely in 
 following streams showing such oil films up to the 
 source of the petroleum spring or oil-bearing rock 
 
258 P INSPECTING AND VALUING MINES. 
 
 outcrop. Borings for oil in depth are generally di- 
 rected in accordance with the results found in existing 
 wells of the neighborhood ; though sometimes bore 
 holes are put down in localities far from any previously 
 sunk wells, where geologic reasoning shows the proba- 
 bility of the presence underground of oil-bearing 
 strata which have been proved elsewhere. Boring for 
 oil is a special trade, based partly upon theoretical 
 and geological considerations but more especially 
 upon local experience. 
 
 iv. GASEOUS. 
 
 NATUKAL GAS also is a hydrocarbon, something like 
 the "marsh gas" which sometimes rises from swamps, 
 and also related to the "fire damp" of coal mines. It 
 is colorless and odorless, and is lighter than ordinary 
 illuminating gas. Its discovery in a new locality 
 usually results from accidental ignition ; in regions 
 where it is already known to exist borings for it are 
 put down in accordance with the indications given by 
 earlier gas wells, or to strike a stratum which has been 
 gas-bearing elsewhere. 
 
CHAPTEE XV. 
 COAL, 
 
 THE literature of coal is so extensive and complete, 
 and coal mining is so essentially a business in itself, 
 that in a work intended chiefly for the use of the pros- 
 pector for ores a long account of coal would be useless 
 and out of place. This chapter will therefore be de- 
 voted to the presentation of only those points which 
 may be serviceable to the prospector who may come 
 across outcrops of coal while searching for other 
 minerals, so that he may be able to estimate their 
 value as aids in the reduction of metallic ores. 
 
 ORIGIN. The general origin of all coal beds is the 
 same. Masses of vegetation were laid down in water 
 in a horizontal position, or nearly so; and then, ow- 
 ing to geological changes, covered up and buried by 
 the rocks we now find above them, undergoing in 
 process of time, through pressure and heat, certain 
 chemical changes, which, according to the period of 
 time which has elapsed since their formation, have 
 been more or less extensive; so that to-day we recog- 
 nize several varieties, distinguished chiefly by their 
 percentages of carbon and volatile matter, imparting 
 to them different qualities. The character of the 
 rocks on which beds of salt, gypsum, iron ore, etc., are 
 deposited is purely accidental and unimportant, but 
 in the case of coal the wide marshes demanded a reten- 
 
260 PROSPECTING- AND VALUING MINES. 
 
 tive bottom to prevent drainage, and we consequently 
 usually find a floor of clay, often fire clay, without 
 which we cannot imagine the formation of such 
 enormous accumulations of vegetable matter, which 
 before compression reduced them to their present con- 
 dition must have had a thickness from ten to twenty 
 times that which they now exhibit. The edges of coal 
 deposits are likely to be largely contaminated with 
 sand and clay or other waste matter; and it is easy to 
 see, if the deposit be of small area, how this worthless 
 margin may form a much larger proportion of the 
 whole bed than in those of greater extent, as in the 
 case of coal we must picture to ourselves immense 
 level marshy tracts, covered with a dense, luxuriant 
 vegetation which would certainly intercept any wind- 
 blown debris before it had traveled far from the 
 margins of the swamp, or would entangle in its roots 
 the sediment brought down by streams, the velocity of 
 whose currents would be promptly checked, and con- 
 sequently they would drop their burden. 
 
 COMPOSITION. As a general proposition the percent- 
 age of carbon is greatest in those coals which are 
 the oldest geologically. Coal contains a certain 
 amount of "fixed" carbon, or that which remains after 
 coking, and also a certain amount of carbon in com- 
 bination with hydrogen, oxygen and nitrogen, forming 
 the volatile portion ; the remainder is earthy matter 
 (forming ash) and moisture. The following table, 
 from Andre's "Practical Treatise on Coal MiniDg" 
 (which may be consulted for all details), is very in- 
 structive, showing that with age, in the sense of geo- 
 logic time, coal loses the gaseous elements, particularly 
 oxygen and nitrogen, consequently containing a larger 
 percentage of carbon, and steadily increasing in 
 specific gravity. An important exception is found in 
 the case of comparatively recent coals which have 
 been heated and altered by the proximity (not actual 
 contact) of igneous dikes or overflows, producing the 
 
COAL. 
 
 261 
 
 same effect as age. Colorado and 
 are examples. The percentages 
 spective of ash and moisture. 
 
 are 
 
 other anthracites 
 calculated irre- 
 
 COMPARISON OF CARBONACEOUS SUBSTANCES. 
 
 Substance. 
 
 Specific 
 Gravity. 
 
 Carbon. 
 
 Hydro- 
 gen. 
 
 Oxygen 
 and 
 Nitrogen. 
 
 Wood mean of 12 kinds 
 
 Per. Cent 
 0.91 
 0.99 
 1.25 
 
 1.27 
 
 1.30 
 1.37 
 1.50 
 
 Per Cent. 
 49.00 
 59.30 
 72.37 
 
 80.07 
 
 86.17 
 91.00 
 92.50 
 
 Per Cen 
 6.25 
 6.52 
 5.18 
 5.53 
 
 5.21 
 4.75 
 3.75 
 
 Per Cent. 
 44.75 
 34.18 
 23.45 
 13.50 
 
 8.62 
 5.25 
 3.75 
 
 Peat mean of 12 samples 
 
 Lignite mean of 12 samples .... 
 
 Cannel coal 
 
 Bituminous coal mean of 3 divi- 
 sions 
 
 Semi-bituminous coal mean 
 
 Anthracite coal mean 
 
 
 CLASSIFICATION. 'The classification and names of coal 
 are based on the foregoing percentages. A portion of 
 the gases are combined to form water, while the re- 
 mainder of the gases are combined with a portion of 
 the carbon in the form of volatile matter, leaving a 
 balance of carbon, which is known as the " fixed" car- 
 bon, and is that portion which is left as coke when 
 the volatile matter has been extracted by distillation. 
 The varying proportions of these materials render the 
 different kinds of coal suitable for different purposes. 
 Water in all cases is a detriment to the coal, as it must 
 be driven off in th form of steam at the expense of a 
 portion of the carbon, which is thus lost for heating 
 purposes. 
 
 The following classification of coals is taken from 
 Andre, and is based on the amount of coke produced 
 by distillation. The "coke" in this case does not 
 mean commercial coke, but the residue left in labora- 
 tory tests. Neither anthracite at one extreme nor 
 lignite at the other make true coke. 
 
PROSPECTING AND VALUING MINES. 
 
 CLASSIFICATION OF COALS. 
 
 Name of Coal. 
 
 Coke, 
 Per Cent. 
 
 Volatile 
 Matter, 
 Per Cent. 
 
 Character of Coke. 
 
 
 93-88 
 
 8-12 
 
 Brittle and powdery. 
 
 Semi-bituminous 
 
 88-82 
 
 12-18 
 
 Brittle and powdery 
 
 Bituminous 
 1 Clear-burning 
 
 82-74 
 
 18 26 
 
 Good. 
 
 
 74-68 
 
 26-32 
 
 Good. 
 
 3 Smoky or fuliginous ... 
 
 68-60 
 
 32-40 
 
 Porous, friable. 
 
 
 60-50 
 
 40-50 
 
 Soft, powdery. 
 
 Lignite or brown coal 
 
 50 
 
 50 
 
 
 
 
 
 
 DISTINGUISHING CHARACTERS OF COALS. Anthracite 
 Its structure is perfectly homogeneous, its density 
 greater than that of other kinds of coal, and it has a 
 more completely mineralized appearance. Its color is 
 a jet black, with a somewhat vitreous luster, often ex- 
 hibiting a powerful play of colors. It does not 
 (easily) soil the fingers when handled, being very 
 hard and firm. In the harder examples, the fracture 
 is distinctly conchoidal, but when of a more tender 
 character it frequently breaks into small cubical 
 lumps. Anthracite burns with a feeble flame, blue 
 when the supply of oxygen is insufficient, and often 
 decrepitates much in burning. It ignites with diffi- 
 culty, and is slowly consumed, but when in a state of 
 perfect combustion it evolves intense heat. The 
 quality of hardness possessed by anthracite enables it 
 to be transported from place to place without injury, 
 while that of evolving great heat without smoke 
 renclers it peculiarly suitable for many purposes, as in 
 the generation of steam, and employment in distil- 
 leries, breweries, or in lime or brick kilns. In 
 America it is largely used for domestic purposes; also 
 for steam-making on naval vessels at times, and in 
 cities where "anti-smoke" ordinances prohibit the use 
 of bituminous. 
 
 Semi- anthracite is a term sometimes used to indi- 
 cate a grade between strictly anthracite and semi- 
 bituminous, 
 
COAL. 263 
 
 Semi-bituminous Coal occurs Dext above the anthra- 
 cites in geological order. Occupying a higher posi- 
 tion, it has been less exposed to the action of heat and 
 other metamorphic agencies, and has consequently 
 retained a larger proportion of its volatile matter. 
 Between the anthracitous and the semi-bituminous 
 classes, however, the line of division is purely arbi- 
 trary, since from anthracite to cannel there is every 
 grade of composition. Its color is usually a dull 
 black and its fracture subconchoidal. It frequently 
 exhibits a peculiar fibrous structure, passing into a 
 remarkable toothed arrangement of the particles, 
 called " cone-in-cone" or crystallized coal. It burns 
 with a slightly more abundant flame than coals of the 
 anthracitous class, and evolves more smoke, but not 
 in dense volumes. It possesses the dry character of 
 the latter class, and from its freedom from a liability 
 to cake together, it is sometimes called "free-burn- 
 ing/' and " steam coal." 
 
 Bituminous Coal (Clear-burning 1). "The varie- 
 ties of the clear-burning division are the poorest in 
 volatile matter. They are similar in texture to those 
 of the preceding class, but generally of a duller luster. 
 They are very tender, and break with an even or an 
 irregular fracture, and in consequence of the very per- 
 fect development of the cleat* have always a tendency 
 to break up into small cubical lumps. These coals 
 kindle with difficulty, and burn away slowly with a 
 short, clear, bluish flame, and very little smoke. 
 When reduced to a powder and heated in a close 
 vessel they fuse and agglomerate into a dense and 
 strongly coherent coke, a property which renders 
 them extremely- valuable for manufacturing purposes. 
 Both in quality and quantity the coke obtained from 
 the clear-burning coals is superior to that obtained 
 from any of the more bituminous varieties." 
 
 * Cleat s the system of parallel joints at right angles to the bedding of 
 the coal. 
 
264 PROSPECTING AND VALUING MINES. 
 
 Flaming Coal (Bituminous 2). "The coals of 
 tbis class are richer in volatile matters than the fore- 
 going, a circumstance to which they owe their char- 
 acteristic flaming quality. Their structure is dis- 
 tinctly laminated, and their color black and glossy. 
 When reduced to powder, however, their color is a 
 dark brown. They kindle without difficulty, and 
 burn away somewhat rapidly with a long white flame. 
 Coals of this class become partially fused when 
 strongly heated, and while in a fused state swell into 
 a spongy mass, giving off bubbles of gas, which burns 
 with a bright flame. This property of agglutinating 
 in the fire allows the small coal to be burned which 
 would otherwise be useless, or to be converted into 
 coke, of which it produces an excellent quality. To 
 this property, also, these coals owe the name of 'cak- 
 ing* coal, which has been applied to it in common 
 with some other varieties of the same class/' 
 
 Fuliginous Coal (Bituminous 3) " contain a very 
 large proportion of volatile matter. Hence they 
 kindle readily, and burn away rapidly with a long 
 yellow smoky flame. They are somewhat hard and 
 strong, and their fracture is rather shaly. Coals of 
 this character fuse in the fire like the flaming varieties 
 but they do not agglomerate or cake into so compact 
 a mass. The gas obtained from them is abundant and 
 of a high illuminating power, but the coke obtained 
 from this division is friable and porous, and unfit for 
 many purposes. " 
 
 Gas Coal (Bituminous 4). "All of the foregoing 
 coals occur in the so-called Carboniferous period, but 
 some of the present section are found in beds of later 
 geological times. They are distinguished by the very 
 large proportion of volatile matter which they con- 
 tain, and to this circumstance it is due that they do 
 not cake when heated. Experience has shown that 
 coal becomes caking when the proportion of carbon 
 reaches 80%, and that of the hydrogen descends below 
 
COAL. 265 
 
 on the other hand, when the proportion of 
 hydrogen becomes very small and that of the carbon 
 large, as in the anthracites, the same non-caking qual- 
 ities result. The gaseous coals are of a brownish 
 black color and of a dull luster. When reduced to 
 powder they are quite brown. They are generally 
 hard, compact and strong; their fracture is even to 
 conchoidal. Coals of this class kindle even more 
 readily than the fuliginous varieties, and they burn 
 away rapidly with a long flame. The coke obtained 
 from coals of this class is of a soft and pulverulent or 
 powdery character and useless for commercial pur- 
 poses." 
 
 Cannel Goal "naturally falls under the head of a 
 gaseous coal, though differing much in appearance. 
 It is a very hard compact coal, of a black or brownish 
 black color, sometimes glossy, but more frequently 
 dull in luster. It does not soil the fingers when 
 handled, and it is capable of taking a high polish. It 
 breaks with a flat conchoidal fracture, and is distin- 
 guished from ordinary coals by the absence of a 
 laminated structure. This is a mark of its highest 
 perfection, for when it comes earthy and impure the 
 laminated structure is developed. It kindles very 
 readily, and burns away in the hand with a very 
 abundant white flame. It is now employed almost 
 exclusively (except for grate fires) for gas making, for 
 which purpose it commands a high price. Seams of 
 caunel occur in certain districts with ordinary coal, 
 and often form the upper portion of a seam of bitumi- 
 nous coal, and occasionally of a bed of black-band 
 ironstone." The splint coal of West Virginia aad other 
 States somewhat resembles can nel in appearance and 
 qualities, but is higher in the scale of fixed carbon. 
 
 Lignite or Brown Goal "occurs in the more recent 
 geological formations. The processes of mineraliza- 
 tion having been less completely effected than in the 
 older coals, they exhibit their vegetable structure 
 
266 PROSPECTING AND VALUING MINES. 
 
 more completely, and as an effect of the same cause 
 they retain a much larger proportion of the volatile 
 matters. In color they vary from brown to pitch 
 black. Their luster is generally dull, but sometimes 
 resinous; the fracture is various. They burn readily 
 with a dull flame, emitting much srnoke, and an un- 
 pleasanfc odor. In consequence of the small propor- 
 tion of carbon and the large quantity of water which 
 the3 r contain, the brown coals do not possess great 
 heating power. They are largely developed in the 
 western States of America. On account of the large 
 amount of water they 'slack' into small fragments 
 when exposed to the air and sun, the large blocks soon 
 showing a multitude of cracks/' 
 
 IMPURITIES IN GOAL. -In all the foregoing remarks 
 the coal is supposed to be free from impurities, but as 
 a matter of fact this is seldom the case. "The impuri- 
 ties may be classed as essential and accidental; the 
 former being those which entered into the composition 
 of the vegetable substances from which the coal was 
 formed, and the latter those which have been inter- 
 mixed with these substances. The essential impurities 
 consist of silica, alumina, lime, magnesia and oxide of 
 iron, to which may be added water. The accidental 
 impurities may consist of any substance other than 
 the elements mentioned. Some of these have been in- 
 troduced by the infiltration of water holding the sub- 
 stances in solution. In general the accidental impuri- 
 ties consist of earthy matters, which were probably 
 deposited from water flowing among the coal vegeta- 
 tion, or blown thither by the winds. The quantity of 
 earthy impurities present in any given sample of coal 
 is estimated by weighing the ash after combustion. 
 When the weight of the ash so left does not exceed 
 5% of that of the coal, the latter is considered very 
 pure. Above that proportion it begins to lose in 
 quality and becomes hard and shaly in structure. 
 
 "A common impurity is iron pyrite, or sulphuret of 
 
COAL. 267 
 
 iron, a substance known to coal miners as 'brasses.' 
 Pyrite occurs sometimes as a deposit filling the cracks 
 and fissures in the coal; sometimes as thin beds. It is 
 not infrequently met with running with a line of part- 
 ing, or it occurs as crystals disseminated throughout 
 the mass; and more often as minute particles imper- 
 ceptible to the naked eye. The presence of iron. pyrite 
 detracts greatly from the value of coal by rendering it 
 unsuitable for many important purposes. Coal con- 
 taining this mineral is totally unfit for [iron and steel] 
 metallurgical purposes [though available for other 
 metallurgical uses, as in roasting and smelting certain 
 metals], and it cannot be burned anywhere in contact 
 with iron without serious injury to the latter. Hence 
 it cannot be employed for the generation of steam, as 
 its corroding action would rapidly destroy the fire- 
 grating and the lower plates of the boiler. Moreover, 
 pyrite is decomposed by moisture and converted into 
 a sulphate, and the expansion which takes place dur- 
 ing the process tends to break the coal into very small 
 lumps and even to powder. This decomposition is 
 often accompanied by great heat, and spontaneous 
 combustion is not infrequently occasioned thereby. 
 Heaps of brassy small coal and rubbish lying as refuse 
 on the pit bank often take fire from this cause in wet 
 weather, and, which is of far more disastrous conse- 
 quence, the exposed coal in the workings will some- 
 times become ignited." 
 
 While no coal is free from impurities, the variation 
 is great both as to the amount of ash left after burn- 
 ing and of water. From the nature of the origin of 
 coal, as has been already seen, there must be a thin 
 edge to the bed entirely round its circumference, and 
 this will naturally contain a larger percentage of im- 
 purities than the central mass, "where they may be 
 scattered through the entire thickness of the seam or 
 consist of thin alternate layers. Sometimes one or 
 more of these layers will extend over a large area and 
 
268 PROSPECTING AND VALUING MINES. 
 
 frequently assist materially in mining the coal. In 
 such cases the upper seam may have quite a different 
 character to the lower one and may be mined sepa- 
 rately. 
 
 TEST FOB COKING QUALITIES. Some coals -which 
 appear to contain the requisite ingredients to make 
 good coke refuse to coke except under particular 
 treatment, and only a series of analyses, followed by 
 working tests, can determine tha ultimate value of a 
 field, or to what purpose the product may be best 
 adapted; but the prospector may readily ascertain for 
 himself by the camp fire, whether his find comes 
 within the coking series by the following means: 
 Take a clay pipe with a moderately long stem ; fill the 
 bowl with clean powdered coal, and then carefully 
 lute, or stop the top with stiff, well-worked clay. It 
 is not advisable to fill the bowl too full, as if the coal 
 should prove to coke, it will swell on heating, and 
 raise the clay cap, admitting air, and the experiment 
 will be a failure, as the coal will take fire. When pre- 
 pared, place the bowl of the pipe in the fire, heating 
 it gently at first to dry the clay without cracking, and 
 then more rapidly to a white heat. Smoke and gas 
 will be given off (through the stem), which will burn 
 freely, being made up of the volatile matter, water 
 and sulphur. When this ceases the operation is com- 
 plete. Take the pipe from the fire, and if the coal 
 will coke, the bowl will be found to contain a solid 
 mass of ccke of a bright dark gray color, hard and 
 compact, if good; but easily crumbling to powder if 
 of poor quality. If the luting or stopper of clay has 
 cracked it may be partially burned up, but a few ex- 
 periments will easily give the requisite skill to make 
 the test. A large portion (practically all) of the ash, 
 of course, goes into the coke. 
 
 The ash is determined by weighing the earthy 
 matter left after burning a definite weight of dry coal 
 in the open air (by which the carbon as well as the 
 
CO A L. 269 
 
 volatile matter is consumed), and calculating the per- 
 centage. Analysis alone can determine this accu- 
 rately and furnish tne information whether it is a 
 high or low grade coal, in case it refuses to coke. 
 
 COMMEECIAL VALUE. The prospector's interest in a 
 coal discovery centers in the question whether it will 
 become a business success on development. This 
 depends on the number, thickness and dip of the 
 workable beds; on an abundant supply of cheap labor, 
 to keep the cost of mining, sorting and washing at a 
 low figure; cheap transportation by land or water; 
 and freedom from competition with coals of its own 
 class, thus filling a vacant place in the market. Many 
 or all of these items may be largely modified if the 
 coal is found in a region otherwise largely devoid of 
 fuel, as many of our interior mining districts, in 
 which the price might be greatly enhanced, and the 
 product yet have a ready sale: but the conditions be- 
 come emphasized, especially as regards coal for domes- 
 tic purposes, in densely wooded districts like western 
 Washington. 
 
 But with all conditions apparently favorable, the 
 exploration of the field may result in failure, from 
 excessive and unexpected "faulting" of the coal largely 
 increasing the cost of working; by the intrusion of 
 eruptive rocks into the coal seams, destroying the 
 coal ; by a change in the character of the coal ; by the 
 thinning out of the beds; or the opening of other 
 mines better located with regard to some item which 
 gives them an advantage in the market. 
 
 PROSPECTING. There is not much to be said on this 
 subject. The first discovery is likely to be purely ac- 
 cidental, but when made a few simple rules will assist 
 in tracing the outcrop. The first thing is to get a 
 good knowledge of the rocks between which the coal is 
 found and their relation to other rocks above and below 
 them, keeping a sharp lookout while doing this for 
 any fossils such as shells or plants. After acquiring 
 
270 PROSPECTING AND VALUING MINES. 
 
 this knowledge, the search must be confined to the 
 region occupied by these floor and roof rocks, and the 
 knowledge gained of the associated rocks will tell the 
 searcher in which direction he must look, if he acci- 
 dentally has wandered beyond the limits of the coal- 
 bearing series, because, from the way in which the 
 beds were formed originally, they are now found more 
 or less parallel to the junction of two different kinds 
 of rock. 
 
 If the country has been much tilted the outcrop 
 may follow quite a wavy line or even apparently run 
 in a semicircle, but having by the means just stated 
 defined the limits of the area in which coal is likely 
 to be found, the search may be continued by follow- 
 ing up the ravines which cut this formation. In a 
 densely wooded country this kind of exploration is 
 difficult, but as the coal is softer than the rocks in 
 which it is found, tljere is usually a sharp break or 
 drop in the bed of the ravine at the point where the 
 coal crosses, and all such places should be carefully 
 examined. Beyond this the prospector must use his 
 own judgment. 
 
 As coal suffers from exposure to the elements, it is 
 likely that the outcrop will be inferior to the coal 
 found at a little depth below, but whenever the roof 
 and floor become solid and show no signs of decay, the 
 coal there found may be taken as a general, but very 
 rough, sample of the deposit. 
 
 Provided all the surroundings appear satisfactory a 
 complete series of borings should be made to prove the 
 condition of the beds as regards "faulting, " but at 
 this point the work of the prospector ends, and that of 
 the engineer begins. 
 
CHAPTER XVI. 
 GOLD GRAVEL DEPOSITS. 
 
 GRAVEL MINING or washing is carried on to obtain 
 placer gold, platinum, tin, diamonds and some other 
 less important substances, which are found during the 
 search for the more valuable ones. When the water 
 used in the process is applied under pressure, the term 
 "hydraulic mining" is applied to the operation. 
 
 The deposits operated upon may be glacial drift; 
 the beds and hillsides of modern streams, which are 
 generally called "placers," and the operation "placer 
 mining;" or the gravel accumulated in the beds of 
 ancient streams, long since dry, and not infrequently 
 located high on the mountain sides above all the pres- 
 ent rivers, may be attacked by hydraulic methods, 
 when not covered with a lava cap; or "drifted" by 
 means of tunnels, in a manner similar to coal mining, 
 when the cap of the mountain is too hard to be 
 removed economically, or the top gravel too poor to 
 pay for washing, or water too scant in supply or with 
 too small a head or pressure to admit of hydraulicking. 
 The working of ordinary placers by ground sluices or 
 by sluice boxes is so well .mown that it is not neces- 
 sary here to enter into any details. 
 
 In studying gravel deposits we must remember that 
 the laws governing the operations of nature have been 
 the same for all time; that the forces have been the 
 same, though they may have operated with greater 
 activity ; and that any explanation of the phenomena 
 which is not in strict accordance with these laws must 
 
272 PROSPECTING AND VALUING MINES. 
 
 inevitably be erroneous and defective. This caution 
 is the more necessary as we have to deal largely in our 
 explorations with things that we cannot see and can 
 only base our surmises as to their condition on the 
 laws which we know to govern the same circumstances 
 in the world which is open to our inspection. Any 
 proposition which is in direct opposition to these laws 
 should be laid aside promptly as worthless. The 
 importance of this is especially apparent in the open- 
 ing of "drift" mines. 
 
 ORIGIN OF GRAVEL DEPOSITS. All accumulations of 
 gravel and sand have been made by the action of 
 water, either as running streams or sea waves, or by 
 ice as glaciers and icebergs, and result from the wear- 
 ing away of rocks by the action of the air or rain or 
 frost, or all three combined. The nature of their con- 
 tents must therefore depend on the character of the 
 rocks which have been destroyed and the width, depth 
 and velocity of the streams which carried the material 
 to its resting place, or the area over which ice sheets 
 and glaciers or floating ice could carry its burden of 
 soil and rocks before melting and depositing its load. 
 
 As we have seen in studying the filling of mineral 
 veins, the minerals are disseminated through a variety 
 of rocks, and the presence of veins is not necessary, as 
 is so generally supposed, to "feed" the stream. When 
 a stream ceases to show gold in the bed on following 
 it upward, it does not follow that there must be a rich 
 vein in that vicinity, for which we constantly find the 
 miners searching; it may be simply an intimation that 
 the upper limit of the gold-bearing rocks has been 
 reached. We can indeed have good placer diggings 
 in regions where well-defined veins are scarce. If 
 we once thoroughly realize this general distribution 
 of gold in certain belts of rock, the origin of gravel 
 deposits carrying gold, tin or platinum becomes much 
 more easily intelligible. 
 
 When the rock is decomposed by the ordinary action 
 
GOLD GRA VEL DEPOSITS. 273 
 
 of frost or air and rain, the detached particles are con- 
 stantly descending by the steepest line, under the 
 action of gravity or water, and this is usually more or 
 less at right angles to the stream into which they 
 finally find their way. During this descent the par- 
 ticles of gold suffer but little abrasion, as their prog- 
 ress is excessively slow, and they undergo no sorting 
 into sizes, other than what would result from the 
 greater momentum of the larger particles, causing 
 them to travel further on a steep side hill where but 
 little surface water and rivulets acted; but if there 
 were much water coming down the side hills, the reverse 
 might occur, the larger gold particles resisting more 
 than the light flaky ones. On entering the water their 
 fate depends on the depth of water and the velocity of 
 the stream. If the latter is great, the finer flaky par- 
 ticles, which even in still water descend to the bottom 
 very slowly, will be swept away with the sand on their 
 seaward journey, only the heavier pieces reaching the 
 bottom, where they will continue to sink into the river 
 bed by their superior weight as long as the surface is 
 very soft or slightly agitated. The less the velocity, 
 the smaller will be the amount thus swept away. In 
 cases where the gold has not been much subject to the 
 action of water for continuous periods, it may retain 
 its crystallized or angular form, and this is usually an 
 indication of the vicinity of a vein, especially if por- 
 tions of quartz are still attached to the specimens. 
 The smoothing and flattening of nuggets and grains of 
 river gold is probably due to a large extent, if not alto- 
 gether, to the impact of heavy rocks and the polishing 
 action of sand and gravel as they are swept over it in 
 the river bottom, just as such material polishes and 
 wears away the angles of bowlders or solid masses pro- 
 jecting from the bottom of the stream. It does not 
 seem probable that the coarse gold has ever traveled 
 very far from the point where it first found lodgment 
 in the river, but the very finest particles may be trans- 
 
274 PROSPECTING AND VALUING MINES. 
 
 ported many miles. Gold derived from the decay of 
 either iron or arsenical pyrites rnay be so excessively 
 fine that it will never find a lodgment on the bottom 
 until the sediment with which it is mixed reaches 
 quiescent or perfectly tranquil waters. 
 
 RIVER DEPOSITS. 'All rivers and streams may be 
 compared to immense sluice boxes in which the heavier 
 particles have been retained, and the lighter ones 
 washed away, while nature has been carving out the 
 river basins with all the forces at her command, pre- 
 senting for our final clean up the contents of an 
 immense mass of material so inexpressibly poor in 
 gold, platinum, tin, etc., that human efforts could not 
 have undertaken the task. Some idea of the extent of 
 this concentration may be obtained when we remem- 
 ber that we have absolute evidence that some of the 
 river channels in California have been cut down fully 
 2,000ft. below the surface as it exists to-day. In such 
 a valley with a width of 6,000 ft. from rim to rim, 
 6,000,000 cu. ft. of rock have bean removed (6,GOOX 
 2,000-=-2) to carve out one running foot of its length, 
 and all that remains may be a deposit 400 ft. wide by an 
 average depth of 20 ft., or 8,000 cu. ft. to the running 
 foot of the ralley, or in other words 222,222 cu. yds. 
 have been concentrated down to about 300 in round 
 numbers (say 740:1). If the value of this be $1 per 
 yd. the original material would only have contained 
 about one and a third mills in the same quantity 
 ($0.00135). 
 
 During this process a portion of the finer gold has 
 been carried down the stream to flatter regions by the 
 strength of the current, but the coarser has been 
 retained, probably not far from its source, the extent 
 of the deposit varying considerably with the character 
 of the bottom of the channel, the bowlders in which 
 act the part of riffles or lining in the artificial sluice 
 box. 
 
 Modern Streams.^ In the case of the modern moun* 
 
GOLD GRAVEL DEPOSITS. 275 
 
 tain streams, the velocity arid quantity of water have 
 been so adjusted to the amount of material brought 
 down, that the bulk of the finer debris or waste has 
 been carried down to the valleys below, leaving only 
 the coarser gravel and bowlders in the beds of the 
 ravines filled in with a certain percentage of fine ma- 
 terial in the interspaces, making the deposits compar- 
 atively shallow and rich, and there does not appear to 
 have been much change from time to time in the con- 
 ditions under which they were made. 
 
 Ancient Ewers. When we come to study the 
 ancient or buried streams, as they existed prior to the 
 last great outbreak of lavas, in which the deposits are 
 sometimes 400 ft. thick or over, we shall find evi- 
 dences of great alterations in the flow of water from 
 time to time, and the character and quantity of the 
 material carried by it in suspension. If we trace the 
 history of one of these old river channels, as read by the 
 records it contains within itself, construed by the laws 
 of nature in operation to-day, as in the past, we shall 
 get a clearer idea of their structure than in any other 
 way and be better prepared to open them for success- 
 ful mining. 
 
 Bedrock; Eim; Grade. The rock on which the 
 gravel deposits lie is called the "bedrock " (see pi. 10, 
 figs. 1 to 6), and the point where the bedrock and gravel 
 or lava are seen in contact on the surface the "rim," 
 as in pi. 10, fig. 4, a,g; fig. 5, a. The inclination of 
 the bottom of the stream in the direction of its flow 
 is known as the "grade" of the channel. By com- 
 parison with known mountain ranges, it will be seen 
 that all streams have steep grades near their sources, 
 becoming flatter and flatter as they approach the low- 
 land valleys. 
 
 Bottom Gravels. The first stage was similar to the 
 conditions surrounding our modern streams. The 
 wearing away of the hills was carried on comparatively 
 slowly, the streams were of moderate velocity, carry- 
 
2?6 PROSPECTING AND VALUING MINES. 
 
 ing off the waste and leaving the coarse gravel and 
 gold in the river beds. Large quantities of material 
 brought down in flood time were gradually panned out 
 during the drier seasons, as we know by the thin 
 layers of iron sand, such as we see cleaned up by the 
 lap of the stream on our present river banks and sea 
 beaches, leaving the contained gold to enrich the bot- 
 tom deposits. In this way the so-called " bottom" 
 gravels, which are the exact counterpart of the modern 
 placers, were formed, by the alternate flood deposits 
 and slackwater panning. These bottom gravels are 
 usually the only ones which will pay for the slow 
 process of drifting; and sometimes, when too poor for 
 this method of working, the entire "top dirt" has to 
 be removed, even if it barely cover expenses. 
 
 The Deep Beds. Then commenced a change in the 
 surroundings. The quantity of sediment sent down 
 had been so great that the streams at the mouths of 
 the mountain valleys became filled up and the sedi- 
 ments began to accumulate in the valleys themselves, 
 and from that time the material deposited assumed a 
 flat grade, and the filling up of the bed of the stream 
 proceeded at a rapid rate, creeping upward as the 
 lower portions became more and more choked, until 
 in some cases we find the thickness of these beds run- 
 ning up into the hundreds of feet. The gold in such 
 material is naturally fine, and not having undergone 
 the process of concentration to such an extent as the 
 bottom gravel is much less in quantity for equal bulk 
 of material; but there is no sharply defined line be- 
 tween the two, although the depreciation takes place 
 rapidly until the general average value of the upper 
 fine beds is reached. This results from the fact that 
 there is to some extent a combination of both condi- 
 tions at or near the point where the flat grade of the 
 valley met the steeper slope of the mountain stream. 
 As the valley filled up the river channel naturally be- 
 came wider, the sheet of water thinner and in conse- 
 
GOLD GRA VEL DEPOSITS. 277 
 
 quence less and less able to carry any burden in sus- 
 pension, and it is easy to picture a wide sandy bottom 
 with changing channels, bars and stagnant pools ob- 
 structed by snags and log jams. All the conditions 
 are beautifully shown in the deep gravel workings 
 at Sailor Flat in Nevada County, Cal. PI. 12, fig. 7, 
 shows a portion of the gravel bank at this place, and 
 the constant changes of the channels can be read in 
 the various deposits of sand and gravel lying uncon- 
 formably on each other. The black marks in this 
 figure show the position of pieces of petrified wood, 
 which is found in enormous quantities in every con- 
 ceivable form of petrifaction. Sometimes the trees 
 are imbedded singly; at other points they have ac- 
 cumulated on bars aud are massed together as we see 
 them in modern streams after floods. In the shallow 
 pools, the falling leaves have accumulated in the fine 
 silt or mud, which now splits in very thin layers, and 
 reveals a wonderful variety of leaves, the imprints of 
 which are in an excellent state of preservation. 
 
 That there were occasional periods of drought when 
 the water was comparatively free of sediment, yet with 
 a velocity sufficient to pick up and remove the finer 
 sand to a certain extent, is shown by the thin beds of 
 fine gravel which can be seen on the face of the bank, 
 and which by their superior richness indicate a certain 
 amount of concentration, as in the bottom gravels. In 
 a few cases these beds have become sufficiently thick 
 and enriched to pay for drifting, as in the case of tbe 
 Breece & Wheeler mine in California, of which a gen- 
 eralized cross section is shown in pi. 11, fig. 2. The 
 upper tunnel was run on such a deposit, so cemented 
 together by the iron which remained among the 
 gravel, as a part of the concentrates, that it had to be 
 crushed in a mill to save the gold. On pi. 10. fi^s. 1, 
 2 and 3, the so-called top dirt is shown by c, the bot- 
 tom dirt being indicated by the solid black at g. The 
 modern placer deposits are shown at e t e,e. 
 
278 PROSPECTING AND VALUING MINES. 
 
 Pipeclay. The beginning of the third stage com- 
 mences with the renewed volcanic activity. The de- 
 position of sand and gravel ceased and immense beds 
 of clay, called by the miners " pipeclay," sometimes 
 reaching a thickess of 200 ft, as at Cherokee Flat in 
 Butte County, were laid down. Afc other points we 
 have deposits of rounded bowlders like cobblestones, 
 and it is not unlikely that these deposits were derived 
 from the earlier outbreaks of the volcanoes, accom- 
 panied by excessive rainfall, which washed the ejected 
 matter into the ravines, the finer material, as in all 
 other cases, being carried furthest from its source. 
 Most of the bowlders in ordinary placer ground are 
 merely waterworn fragments of local rocks; the large 
 proportion of quartz bowlders being due to their hard- 
 ness. It is certain, however, that immediately succeed- 
 ing these bowlders and clay, immense outbursts of 
 lava poured into the river bottoms and filled them 
 from bank to bank. A case where a bed of sinter 
 (volcanic ash) separates unconformable gravel beds is 
 shown in pi. 12, fig. 6, where the sinter bed appears 
 to have been tilted after deposition. 
 
 Lava Cap. Some of the lava beds are over 100 ft. 
 in thickness and form to-day conspicuous objects in 
 the landscapes of the gold regions of California, where 
 they cap hills called "table mountains," from their 
 nearly level summits as seen against the sky, and their 
 precipitous sides. In pi. 10, figs. 1, 2 and 3, the pipe- 
 clay is shown by b and the lava cap by a. With the 
 formation of the lava cap the process of filling was 
 completed. PI. 10, fig. 1, shows the order of succes- 
 sion -bottom gravel, g; fine gravel and sand, c; pipe- 
 clay, b; lava, a. The dark shaded portion shows a 
 cross section of a mountain with its ravines as they 
 exist to-day. The dotted lines m,m, show the hills 
 on either side of the valley as they existed during the 
 process of filling, and the horizontal dotted lines r,s,t, 
 the continuation of the beds a,6,c, before they were 
 worn away. 
 
GOLD OR A VEL DEPOSITS. 279 
 
 Modern Forms. The carving of the country to its 
 present form then began. The river waters on resum- 
 ing their sway were diverted into new channels, and 
 in most cases two streams were formed out of the orig- 
 inal one. When lava Hows into a confined channel 
 such as a valley, the surface and sides of the stream 
 in contact with the rocks, and especiallj* the thinner 
 edges, cool more rapidly than the central core, which, 
 remaining in a plastic condition, is liable from the 
 pressure behind to break the upper crust. This is 
 consequently piled up in the center of the flow in 
 rugged masses with a higher elevation than the sides. 
 In this way there is formed a depression on each side 
 of the flow next to the valley walls, each of which be- 
 comes a watercourse, indicated by the arrows in fig. 
 1. Owing to the superior hardness of the lava the 
 cutting away of the new channels took place largely at 
 the expense of the rocks forming the walls of the 
 valley. By degrees these were eaten away below the 
 level of the under side of the lava, when the process 
 went on more rapidly in the underlying clay and 
 gravel, which on being undermined allowed the ^a 
 to break off in vertical faces forming the characteristic 
 bluffs of the gold regions. While this process was 
 going on large quantities of the finer gravel of 
 the original deposits were carried down to lower 
 regions, taking with it the finest of the gold, the 
 coarse remaining behind, and new placers were form- 
 ing. We have evidence that there were two outbursts 
 of lava, producing similar results. In the lower val- 
 leys the lava caps are entirely basaltic, but in the 
 higher regions the first eruptions were either trachytic 
 or rhyolitic. Both eruptions are well shown in Plumas 
 Co'unty, as in pi. 10, fig. 1. When, after the trachyte 
 outburst, the cutting of the new valleys had proceeded 
 to about half its ultimate extent, the basalt outbreak 
 occurred and invaded some but not all of the streams. 
 In this case the gravel contains pebbles of the lava c<>v- 
 
280 PROSPECTING AND VALUING MINES. 
 
 ering the older channel, a,&,c,(/, along with the quartz 
 gravel which is characteristic of both, but the lava cap 
 is au exceedingly hard, heavy, compact, black iron- 
 like basalt, while the cap of the older channels is a 
 light-colored gray or reddish trachyte, much lighter 
 and coarser in grain than the basalt, and very harsh 
 to the touch on a newly broken face. Being much 
 softer than the basalt and less liable to take columnar 
 forms, it seldom presents such conspicuous bluffs as 
 the basalt. In some cases the basalt lies directly on 
 the gravel; in others there is the usual bed of pipe- 
 clay. If this is absent we may presume that the 
 region was near the source of the lava flow, and that 
 the material forming the clay bed had been washed 
 down to the lower country or had not been ejected in 
 large quantities. The clay beds under the basalt at 
 Cherokee Flat in the foothills of the Sacramento valley 
 are very thick, while in Onion valley, near the summit 
 of the Sierra Nevada, at an altitude of 5,000 ft., they 
 are either very thin or absent. That the eruption of 
 the basalt was later than the formation of the older 
 gravel beds is absolutely proved by the occurrence in 
 the Laporte region, Plumas County, which is located 
 on a trachyte-covered channel of great length and 
 prominence, of a basalt cone overlying a bed of gravel, 
 the pipe or neck of which was penetrated by one of the 
 deep tunnels, and the gravel bed "drifted" all around 
 it, some of the gravel being even surrounded by thin 
 sheets of lava at the outer circumference of the neck 
 which formed the vent. At this particular locality the 
 trachyte cap had been eroded. The structure is shown 
 in pi. 10, fig. 6, where a is the gravel and b the lava 
 cone with its neck or pipe ascending through the bed- 
 rock and gravel. 
 
 Since the basalt outburst, which Was of enormous 
 extent, covering hundreds or even thousands of square 
 miles in California, Oregon and Washington, there 
 seems to have been no serious volcanic disturbance, and 
 
GOLD GRAVEL DEPOSITS. 281 
 
 the denudation went steadily on up to modern times, 
 leaving a mountain range in the case of each flow, of 
 which we have a plan in pi. 11, fig. 1, which repre- 
 sents two modern streams B,E, and the buried ancient 
 river 8U, with those portions of its lateral streams 
 which have not been worn away in the general denuda- 
 tion. L represents the lava and pipeclay capping; G 
 the gravel, and the heavy black lines that portion 
 which is known as the bottom gravel and is suitable 
 for drifting. As the denudation has not progressed 
 evenly, it may happen that the gravel at some points 
 has not been exposed, and the lava apparently lies on 
 the bedrock, as at U. 
 
 "Over/lows." In other places it may be exposed on 
 ona or both sides of the ridge, or the lava cap may have 
 entirely disappeared, as at (7, showing the gravel on 
 the surface all the way across the dividing ridge. The 
 richer bottom gravel found in the lateral branches of 
 the stream will naturally be exposed as at T, T. A 
 common term for these exposures is an "overflow," as 
 though the gravel had been squeezed out of the hill, 
 but that this expression is erroneous is shown from the 
 fact chat the grade or inclination of the bedrock dips 
 into the hill, as shown in pi. 10, fig. 5, where a 
 is the so-called overflow and g the main channel 
 to which it leads. The only exception to this rule 
 is where a remnant of the head of one of these lateral 
 branches is left on the other side of the modern ravine, 
 which has cut the lateral in two without removing the 
 upper portion. Unless this lateral was a large stream, 
 the gravel left will be only a small patch. If a large 
 stream it may present all the features of the main chan- 
 nel if it happened to be covered with lava (which does 
 not necessarily follow). 
 
 Laterals. We also frequently hear miners speak of 
 two or more channels in the hill. Such a condition of 
 things is against all probability; the dividing of a stream 
 into several branches being almost exclusively confined 
 
282 PROSPECTING AND VALUING MINES. 
 
 to those portions which have a flat grade, and does 
 not occur where the grades are such as we find in 
 mountain regions. What does occur is shown on the 
 line OP, pi. 11, fig. 1, where if OP were a tunnel it 
 would cut two bodies of gravel, but they would be only 
 branches of the same stream, the first one encountered, 
 if the tunnel started at 0, having a steeper grade than 
 the second, as lateral branches of a river have almost 
 universally heavier grades than the main river. If 
 there is a sudden expansion of the lava cap, and a more 
 than ordinary width between the rims, such a proposi- 
 tion is almost sure to be found beneath the surface. 
 PI. 10, fig. 2, represents such a structure as would be 
 found on the line OP of pi. 11, fig. 1, where we have 
 two gravel banks c,c, under one lava cap a. Without 
 going into further detail it may be said that all these 
 features can be reproduced in a model, thus proving 
 the general accuracy of the theory of origin. 
 
 Faulted Ancient Channels. It is not to be expected 
 in a country which has been the seat of such compara- 
 tively recent volcanic activity that there will be an 
 absence of faults and dislocations in the channels. Un- 
 fortunately these are numerous and often interfere with 
 the successful working of otherwise valuable property. 
 
 Three examples of such faulting are shown on pi. 
 11, in figs. 4, 5 and 6, all taken from the mining re- 
 gions of Plumas and Sierra counties, Cal. Fig. 4 shows 
 the situation at Grass Flat, near Laporte. Here the 
 fault AB has cut the channel across its general direc- 
 tion, the left hand portion in the figure having been 
 raised, or the right hand portion depressed, as shown. 
 The bedrock at e consequently acted as a dam, and 
 backed up the water flowing down the bedrock, 
 till it formed an underground reservoir P, the drainage 
 outlet of which near A was so near the surface that 
 grassy meadows were formed at C, sustained by the 
 perennial water in P; hence the name. It was impos- 
 sible to work the submerged ground until a long and 
 expensive drain tunnel had been run. 
 
GOLD GRAVEL DEPOSITS. 283 
 
 Fig. 5, same plate, shows a fault running lengthwise 
 of the channel in the pit at Laporte, ab being the dis- 
 location, d the bedrock, c the gravel, and e gravel from 
 the later series of gravels previously described, barren 
 and almost entirely devoid of quartz bowlders. Such 
 a fault is not so detrimental to the working of the de- 
 posit, as it can be followed upstream without interfer- 
 ence; but in such a case as in fig. 6, where the dikes 
 c,c,c, have broken through and dislocated the gravel 
 g, the drifting operations on the bottom gravels, shown 
 in black, became so expensive that while the gravel was 
 rich the expense involved in hunting the continuation 
 of the channel beyond each dike consumed all the 
 profits. 
 
 Folded Gravel Beds. Instead of sharp faulting, 
 gravel beds sometimes show evidence of disturbance 
 in the shape of folds, either in smooth long sweeps or 
 in a complication of smaller waves (pi. 12, figs. 1 and 
 2). Folds are, like faults, often accompaniments of 
 volcanic eruptions, and the gravel may be dragged with 
 the lava sheets. 
 
 HILLSIDE DEPOSITS. These have the same origin as 
 those just described, and are in fact in many cases, if 
 not in all, only their lower portions, which, being at 
 the time of the lava flows below the level of the sea or 
 interior lakes, or for other causes, escaped the lava cap 
 which buried the upper portions of the streams. As 
 the land rose the streams began to cut down into these 
 deposits, concentrating the contained gold on the bars 
 and riffles along their sides, which sustain a constant 
 renewal as the rainfall washes the hillsides down into 
 the river bottoms. 
 
 There is one class of hillside deposits, of local origin, 
 in which part of the gold has, in descending, been con- 
 centrated in pockets formed where favorable rock for- 
 mations occur, as in the case of slates dipping into the 
 hill. These pockets have since been covered over with 
 soil and debris, and some of the gold may have bees 
 
2S4 PROSPECTING AND VALUING MINES. 
 
 carried out of them and further down the hillside, 
 spreading out in fanlike shape. In searching for such 
 pockets the prospector pans out samples of dirt along 
 the foot of the hill, noting where pay or at least some 
 gold begins and ends; then runs a corresponding line 
 of pan tests parallel and higher up, marking the limits 
 of the pay. If this second line is, as is probable, 
 shorter, it will indicate a triangle near the apex of 
 which the pocket is sought for by trenching. 
 
 SEA BEACH DEPOSITS. These are mainly derived 
 from ancient gravel beds, which are reconcentrated by 
 being broken down by the impact of the waves, and 
 sorted by the waves and tides. As these deposits are 
 in most cases the furthest removed from their original 
 source, the contained gold is of the very finest char- 
 acter, and consequently the most difficult to save by 
 mechanical appliances; these difficulties becoming 
 steadily greater as the size of the particles of gold 
 diminishes. If, however, the ocean were operating on 
 solid rocks of any of the various kinds which contain 
 gold, there is no reason why we should not find deposits 
 of conglomerate with coarse gold, gradually fading out 
 into finer and finer sediments with finer and finer gold, 
 as the beds recede into deeper and deeper water, to 
 which only the finer sediments would be carried by the 
 reflux of the waves, or undertow. And further, if the 
 coast line which is being destroyed be gradually sink- 
 ing, as we know to be the case in many localities, just 
 as it is rising in others, we should have such a bed of 
 conglomerates, consisting of the larger waterworn frag- 
 ments, extending over a large area, both in breadth 
 and length, fading out on its upper surface into the 
 finer and poorer material, and in some such way as 
 this the beds of gold-bearing conglomerates may have 
 been formed. The destruction of the shore line would 
 be more rapid and the deposits more extensive than in 
 those cases where the coast is gradually rising, as in 
 this instance the same material would be longer exposed 
 
GOLD GRA VEL DEPOSITS. 285 
 
 to the abrading action of the waves, the formation of 
 conglomerates would be less, and of fine sediments 
 more extensive, and the gold particles would suffer 
 more abrasion and be reduced in size. 
 
 In searching for gold-bearing beach sands, these are 
 naturally to be looked for under bluffs of gravel and 
 conglomerate. A favorable time is after a strong wind 
 blowing along the coast line, which makes cross waves, 
 advantageous for concentration. The best spots will 
 usually be those marked by lines and patches of black 
 sand, which are almost alwa3 r s concentrated wherever 
 any gold is. 
 
 Besides the beach sands proper, gold-bearing sands 
 have been worked, off-shore, by dredging, on the coast 
 of New Zealand. 
 
 GLACIAL DEPOSITS. Under this head are included all 
 those deposits in which ice has played a part in their 
 formation, and we have consequently evidences of more 
 complicated action. As in all other deposits there 
 must be, to start with, a belt of gold-bearing rocks to 
 be removed, or the resulting mass will be barren. 
 Given such a belt of rocks there is no reason why 
 glacial deposits should not contain gold, just as those 
 which have been derived from aerial erosion, but we 
 are likely to find a greater variety in the physical ap- 
 pearance of the gold, either smooth or angular, coarse 
 or fine, because it has been released from the contain- 
 ing rocks by a variety of methods. 
 
 Glaciers transport to the lower valleys, first, the 
 rocks or bowlders which are detached by frost from the 
 exposed bluffs which form their boundary walls; and 
 secondly, the rounded bowlders and sediment which 
 are formed by their grinding action on the rocks over 
 which they travel. If they cross a belt of gold-bearing 
 rocks they must discharge into the valleys the contents 
 of these rocks, along with the remains of the rocks 
 themselves, either in the stream which issues from 
 their "foot," or into the terminal moraine, if they 
 
286 PROSPECTING AND VALUING MINES. 
 
 terminate on land; or the contents may be widely dis- 
 persed by floating ice or icebergs if they terminate in 
 the water. 
 
 While morainal deposits may be unsuited to min- 
 ing ventures, the river deposits resulting from glacia- 
 tion may be worked by machinery suitable to the re- 
 tention of the excessively tine gold, which must neces- 
 sarily be lost in the agitated waters of a sluice box. 
 
 GRAVEL MINING. 
 
 What Constitutes a Workable Gravel Proposition. 
 The elements which go to make a workable gravel mine 
 are : 1, the amount of and distribution of the gold in 
 the gravel; 2, the width, continuity, and extent of the 
 deposit; 3, the character of the bedrock; 4, the depth 
 of the bedrock in relation to the neighboring ravines; 
 5, the grade of the channel or bedrock and freedom 
 from faults; 6, the available dumping ground for the 
 waste material ; 7, the character and amount of the water 
 supply. While all these elements enter into every 
 working proposition, they have widely varying values 
 according to other conditions. 
 
 Placer Mining. This term is sometimes used to in- 
 clude all methods of working placers or gravel deposits; 
 it is here applied in the usual and more restricted sense, 
 excluding hydraulic mining (which involves the use of 
 water under pressure) and covering only those methods 
 of gravel washing (mainl.y in recent placers) in which 
 the water depends for its working qualities simply on 
 its quantity and the grade of the sluice boxes in which 
 it is used. The altitude of the source of supply cuts 
 no figure, except as it affects the grades on which the 
 gravel can be washed. As this condition involves the 
 handling of every pound of gravel by manual labor, or 
 practically so, it is only the richer and consequently 
 the shallower deposits which are available, such as the 
 beds of ravines, river-bars and the shallower adjacent 
 
GOLD GRAVEL DEPOSITS. 287 
 
 deposits. When the former become too poor to work, 
 the miner says he has lost the channel. It is not 
 always meant that there is no longer indication of gold, 
 but its concentration is not sufficient to warrant hand- 
 ling by such slow methods. For the "pan" and the 
 "rocker" a very small quantity of water may be suffi- 
 cient, and the amount of material handled daily is so 
 comparatively small that the question of dumping 
 ground does not trouble the miner, neither does the 
 grade of the channel, nor disturbance by faults, be- 
 cause his appliances are movable on short notice; and 
 the same may be said of the "long torn" or sluice box 
 into which the gravel is shoveled when working on a 
 somewhat larger scale; but the depth and character of 
 the bedrock may be all important, as it is on the bed- 
 rock that the miner finds his chief reward. If he is 
 unable to reach it on account of the influx of water, 
 the cost of wing-damming the stream or pumping may 
 eat up all the profits, and after all the bedrock may be 
 such that it has not been able to retain the gold. 
 
 A perfectly smooth sluice box would permit all the 
 gold to escape, and to avoid this the bottom is either 
 provided with riffles in the shape of slats, or paved 
 with bowlders and sometimes with wooden blocks cut 
 across the grain. All of these methods provide crevices 
 into which the gold drops as it is swept through the 
 boxes by the force of the w j ater, and is thus prevented 
 from escaping. The bedrock in a stream acts in the 
 same way. If perfectly smooth, as at E, pi. 12, tig. 
 3, it may be absolute!} 7 clean, there being no obstruction 
 to give anything a retentive hold. A case of this 
 kind occurred at Gibsonville, Cal., where a long 
 tunnel was run to open a piece of ground lying between 
 two mines which had paid handsomely, only to find on 
 reaching the channel a perfectly smooth bedrock and 
 almost perfectly barren. The most favorable condition 
 is a bedrock pitching down stream as at A, in the same 
 diagram, so that all the crevices are presented to the 
 
388 PROSPECTING AND VALUING MINES. 
 
 impact of the descending material. In such crevices 
 the gold is literally jammed into the rock, and it will 
 usually pay to mine from 6 in. to 1 ft. of its surface 
 .ilong with the gravel, especially if it be softer, as the 
 miners say, "cheesy." A similarly good bedrock is 
 formed by the worn surfaces of limestone B and (7, 
 which being eaten out into irregular holes act as per- 
 fect riffles and give good results, as at Shaw's Flat and 
 Columbia, Cal. ; but less satisfactory returns are 
 usualb' had from slaty rocks pitching up stream as at 
 D, especially if the rocks be hard, as objects slip 
 readily over such surfaces. The application of these 
 principles will soon enable the prospector to work out 
 the problems for himself and test his theoretical knowl- 
 edge by experience. "Potholes," which are smooth 
 round pits worn in the solid rock by the constant fall 
 of water charged with sand, or the grinding action of 
 an imprisoned bowlder, like a pestle in a mortar, are 
 apt to be swept clean of any valuable contents. 
 Bowlders in the bed of the stream of course act as 
 riffles, but when large they add materially to the cost 
 of mining, requiring derricks for their removal and 
 much extra labor. If the gravel is cemented, as is not 
 infrequently the case, it may be necessary to leave it 
 exposed to the air to slack, if the cementing material 
 (as clay) is such as will yield to such simple treat- 
 ment; or it may be even necessary to pass it through 
 a stamp mill; but deposits of this character are not 
 likely to attract the placer miner, as they involve the 
 outlay of considerable capital, which is only warranted 
 by extensive explorations and the proof of extensive 
 deposits. 
 
 Gold Pan. Prospecting is usually done with a large 
 shallow iron pan about 16 in. or more in diameter 
 across the top, by 2| in. deep, with flaring sides, 
 stamped out of a single piece of charcoal sheet iron, 
 called and well known as a "gold pan." Such a pan 
 filled with gravel and fairly heaped in the center will 
 
GOLD GRAVEL DEPOSITS. 289 
 
 hold about 25 Ib. and about 150 pans are usually con- 
 sidered equal to a cubic yard (the number varies with 
 the size of the pan); values of gravel being estimated 
 either by the pan or by the cubic yard and not by the 
 ton. A cent is a piece of gold about -^ in. square and 
 half as thick as a $5 piece, as an approximation to give 
 some comparative idea of size and value. With these 
 figures the prospector can form some idea of 
 what he may be able to do daily, as soon as he has 
 found out how many pans of dirt he can wash daily 
 or how many yards of gravel he can shovel into a 
 sluice box, both of which will vary according to 
 the locality, the character of the ground and the dis- 
 tance to water. Persistent panning is the only thing 
 which will test a gulch. Just as one swallow does not 
 make a summer, one pan of good dirt does not make a 
 mine; nor does the failure to find gold in the first pan 
 prove the locality to be barren. As a usual thing an 
 abundance of quartz pebbles in the gravel is a good 
 indication, and when these are accompanied with an 
 abundance of black sand, minute garnets (transparent 
 and red) and small rounded shot-like pebbles of chrome 
 iron, it is not well to be easily discouraged. The 
 signs of course may fail, but they are what the 
 Mexicans term pintas or colors, and call for a thorough 
 search. If the deposits are too poor to be worked by 
 these primitive methods, but are shown to carry gold (as 
 proved by extensive panning) over a large and well 
 defined area, we may resort to the methods employed in 
 Hydraulic mining, by which we can move and wash 
 per man so vastly an increased quantity of gravel, that 
 ground very poor in its average contents may prove 
 remunerative ; but we must remember that the hydraulic 
 miner always calculates on a rich bottom streak which 
 has to bear the loss, if any, involved in removing the 
 top dirt, which may sometimes be a valueless clay; 
 and generally stops work on the bank when the limits 
 of this bottom streak are reached laterally 
 
290 PROSPECTING AND VALUING MINES. 
 
 By hydraulic mining we understand the use of water 
 under pressure; that is to sa3 r , at some suitable point 
 the stream is turned into pipes which convey it to the 
 ground to be worked ; and by this means we take advan- 
 tage of the weight of the water in the pipes to force 
 large quantities through a nozzle, and secure a power 
 to cut away the gravel bank without the aid of pick 
 or shovel, and wash the material into suitable sluices. 
 According to the pressure or head and the amount 
 of water used, a miner's inch of water* will wash from 
 3 to-10 cu. yd. of gravel. The "head" is the differ- 
 ence in height between the point at which the water 
 enters the pipe and that from which it is discharged; 
 while the "pressure" is equal to the weight of a column 
 of water of this height multiplied by the cross sectional 
 area of the pipe, both in feet, by the weight of 1 cu. ft. 
 of water, from which must be deducted the loss 
 caused by friction (called the friction head) against 
 the sides of the pipe, which will be governed by its 
 length, size and condition of its interior as regards 
 smoothness and cleanliness. This loss is greatest in 
 small pipes. 
 
 It is evident that the grade of the gravel to be 
 worked will depend on the number of yards which can 
 be moved daily by a given quantity of water, and that 
 this will depend on the pressure under which the water 
 is used. To increase this pressure we have to gain 
 altitude, and this forces the head of the water supply 
 further and further back into the mountains; and as 
 this supply must be constant during time of rain and 
 drought alike, we are compelled to build reservoirs, into 
 which the various minor sources of supply are collected 
 and held in reserve. When we remember that mines 
 such as those at North Bloom field and Cherokee Flat, 
 using 2,000 miner's inches or over, consume daily 
 more than 33,000,000 gal., or water sufficient for a city 
 
 * 2,230 cu. ft. a tank 12x12x15 ft. (See Chapter XVII. on Water.) 
 
GOLD GRA VEL DEPOSITS. 291 
 
 of 350,000 inhabitants, it is not to be wondered at that 
 there must sometimes be an expenditure of $400,000 
 or $500,000 on the water plant before a yard of gravel 
 can be washed. With such a heavy preliminary ex- 
 penditure on water, besides the cost of tunnels, 
 sluices, buildings, etc., at the mine, annual repairs and 
 working expenses, we must have correspondingly 
 large deposits of gravel to justify the enterprise. The 
 North Bloomfield Company in 1879 used 931,000 
 miner's inches of water (15,000,000,000 gal.), each inch 
 of which moved on an average about 4 cu. -yds. of 
 gravel, or a total of about 3,724,000 cu. yds., equal to 
 2,310 acres 1 ft. thick, 231 acres 10 ft. thick or 23 
 acres 100 ft. thick. The actual area removed was prob- 
 ably about 7 acres some 300 ft. in depth. These are of 
 course outside figures, but they emphasize very 
 strongly the necessity of a thorough inspection of the 
 water supply, and the facilities for disposing of or im- 
 pounding the debris, before opening an extensive 
 hydraulic proposition. It is time enough to test the 
 quality of the bank when the water and debris ques- 
 tions are settled. 
 
 It would be beyond the proper scope and purpose 
 of the present work to enter into the details of this 
 highly developed method of mining. For such infor- 
 mation the reader is referred to "A Practical Treatise 
 on Hydraulic Mining in California, " by Augustus J. 
 Bowie, Jr.; "Practical Notes on Hydraulic Mining," 
 by Geo. H. Evans; "Manual of Hydraulic Mining 
 for the Use of the Practical Miner, " by Theo. F. Van 
 Wagenen, and other books and current literature. 
 
 Drift Mining.- There are, however, large bodies of 
 gravel which cannot be handled by purely hydraulic 
 methods for one or other of the following reasons: (1) 
 The water supply may be totally inadequate, or the 
 deposit may not justify the expense of bringing it on 
 the ground; (2) the dumping ground also may be in- 
 adequate, or local interests may prevent it from being 
 
292 PROSPECTING AND VALUING MINES. 
 
 made available; (3) the' top dirt may be so thick and 
 worthless as not to warrant its removal ; (4) the de- 
 posit may be entirely capped with lava, which cannot 
 be economically removed; (5) the ravines on either 
 side of the ridge containing the channel may not have 
 been cut down deep enough to enable us to put in a 
 tunnel on a hydraulic grade, or they may be too flat 
 for suitable washing sluices; or (6) the ravines may be 
 so high that their bottom is above that of the old chan- 
 nel, as in pi. 10, fig. 3, and we cannot gain access by a 
 tunnel under any conditions. 
 
 In this last case it will be necessary to work the mine 
 with pumping machinery through either shaft or in- 
 cline, of which latter method the successful Damascus 
 mine in California is a good example; but in this in- 
 stance the incline followed the channel on its descend- 
 ing grade, and did not involve the dead work of shaft- 
 ing, the use of which cannot be said to have been more 
 than partially successful. In all the other cases bed- 
 rock tunnels are resorted to, which are run through 
 the rim on a water grade until the channel is reached, 
 when the gravel is extracted and handled in cars very 
 much in the same way as a coal mine is operated. 
 Water can be accumulated until sufficient gravel is 
 taken from the mine, and a clean up can be made daily, 
 weekly or monthly as the case may be. Having to 
 wash so small a quantity of gravel, comparatively 
 speaking, the sluice boxes may be small, and but little 
 water is required under very slight pressure or none 
 at all, so that the plant is not necessarily costly. Given 
 the gravel, the success of drift mining depends on the 
 location of the tunnel with regard to the bottom of the 
 channel, for many months of labor and many thousands 
 of dollars may be expended on a tunnel which may be 
 valueless if it should unluckily enter the gravel above 
 the bottom of the channel, which it is unable to drain 
 and render workable, as is the case with the lower 
 tunnel in pi. 11, fig. 2. It is infinitely better to be 
 
GOLD GRAVEL DEPOSITS. 293 
 
 too low than too high, but the location of these tunnels 
 is a problem which will severely task the engineer and 
 geologist combined. 
 
 The greater number of the drift mines are located 
 well up in the mountains, on the steeper grades near 
 the head of the old channels, and it is only here and 
 there that the shape of the country has caused the re- 
 moval of the lava cap and exposed the underlying 
 gravel in such a shape that hydraulic work was pos- 
 sible, so that long stretches of the ancient river lie be- 
 tween these isolated spots where the altitude of the 
 bedrock has been ascertained. In these unexplored 
 sections it is only by inference that we know the chan- 
 nel to exist, and numberless abandoned tunnels show 
 how little the miners were acquainted with its struc- 
 ture. To open a mine in such a situation is a delicate 
 task and can only be safely done after boring across 
 the general line of the old river, to ascertain the true 
 position of its deepest portions, and its depth from the 
 present surface. But before this can be done we must 
 determine the course of the old stream so that we may 
 be sure that the bore holes are located across, and do 
 not follow it lengthwise. To make certain of this the 
 rim of the channel on each side of the ridge must be 
 carefully traced out and platted as in pi. 11, fig. 1, 
 noting where the lava, pipeclay or gravel shows in 
 contact with it; and the survey should be extended to 
 include the bed of the ravines on each side of the ridge ; 
 levels should be run the entire length of the rim and 
 the creek bottoms, with full notes of the rocks exposed 
 in the latter, and these levels will disclose the exposed 
 ends o.f the lateral streams T, T, which will outcrop in 
 the lowest parts of the rim. When such a survey is 
 platted we can approximately draw in the center line of 
 the main channel, and of its branches, on the plan; 
 which will cover only the main stream where its rims 
 are approximately parallel, or the main stream and a 
 lateral if there are wide expansions as at OP, and an 
 
294 PROSPECTING AND VALUING MINKS. 
 
 exposure as at /. From these data we can draw an 
 approximate cross section at any point, such as pi. 10, 
 fig. 4, in which the rims are at the same altitude, 
 making the unseen slopes of the old river af and gf, 
 the same as those visible between the rim a and the bed 
 of the creek h. It is evident that under such condi- 
 tions the length of a horizontal tunnel to tap the bottom 
 /would be equal to the width of the channel between 
 the rims a g, as the triangles dca, abf and fbg are all 
 similar. More difficulty will attend the determination 
 of the length on such a line as OP, pi. 11, fig. 1, but 
 the solution is practicable as an approximation. Of 
 course this is not an absolute method, as it is based on 
 the probability of the same rock taking the same or 
 practically the same slopes when worn away under 
 similar conditions, and this maj r not ahvays be the 
 case; but it will do to determine whether a tunnel is 
 feasible, as, if the distance to the creek, as from e 
 to h, is less than one-half the width between the rims, 
 the probabilities are altogether in favor of the condi- 
 tions shown in pi. 10, fig. 3. If the rims are of differ- 
 ent altitudes, as in fig. 3, the center of the old channel 
 will probably be located proportionately nearer the 
 lower rim. 
 
 If this preliminary test prove satisfactory we can 
 locate the borings with certainty, and they should be 
 not less than three in number, probably five or up- 
 wards, as their respective depths may indicate. To 
 ascertain the probable grades of the channel we must 
 extend our investigations to the beds of the creeks on 
 each side of the ridge, as it is important to know be- 
 forehand whether the country is faulted, whether the 
 channel is choked by bowlders, and whether we are 
 likely to encounter flat, moderate or steep grades in 
 the ground when opened, as bad faulting might lead 
 to failure, and might not be disclosed by the borings; 
 bowlders are more difficult to handle even than in the 
 open air; and the grades, as we have seen, largely in- 
 
QOLD GRAVEL DEPOSITS. 295 
 
 fluence the amount of gold in the bedrock gravel. 
 There will probabb r be under any circumstances a slight 
 flattening at the junction of each lateral branch with 
 the main stream. By examining the modern ravines 
 we may possibly find in each a band of rock as F, pi. 
 11, fig. 1, which is easily recognizable, and by using 
 this as a common base, and following each ravine 
 both up and down with a line of levels, we can arrive at 
 a very fair idea of the probabilities where we cannot 
 see the bed of the channel from what is visible in those 
 of modern origin, especially if we find the rock strata 
 occurring in orderly succession in each stream, on all 
 points on which we desire information, whether it be 
 faulting, dip of the rocks, accumulation of bowlders or 
 grade. It would be possible to enlarge on this theme 
 almost indefinitely, but enough has been said to furnish 
 the key to the methods of exploration, which must be 
 varied to suit each particular locality; and the miner, 
 by the aid of this key, can study for himself the 
 chances of success. The boiing is not difficult or ex- 
 pensive, and will be nearly as satisfactory as an open 
 shaft, which will cost more, take more time to sink, 
 and might not after all be suitably located. The 
 trachytic lavas seem to abound in choke-damp or car- 
 bonic acid gas, making good ventilation in the shafts 
 imperative. 
 
 Machine Washing. The operations just spoken of 
 are based on the use of large quantities of water in 
 open sluice boxes, in which there must inevitably be a 
 loss of fine gold, as the records of the undercurrents 
 show. Workings on a large scale have demonstrated 
 the presence in gravel of gold so fine that it is not 
 visible in the pan to the naked eye, just as reasoning 
 demonstrated should be the case in gravels which owe 
 their origin to glacial action, or which contain the 
 products of the decomposition of pyrites. This very 
 fine gold must certainly be swept away in the swirl of 
 such streams as are used in either hydraulic or drift 
 
296 PROSPECTING AND VALUING MINES. 
 
 operations, as it takes a long time to settle even in 
 still water. To save such gold it must be brought into 
 contact with quicksilver in such a way that it cannot 
 escape amalgamation. Such is the intention of all 
 mechanical appliances which have been proposed. It 
 is sufficient to say that by their means gold has been 
 saved which is so infinitely fine that it can be applied 
 as a paint on paper, producing a gilding smoother and 
 thinner than gold leaf. Its presence having been 
 demonstrated, the apparent absence of gold in the de- 
 bris from localities where auriferous pyrites have been 
 largely denuded is explained, and the metal is probably 
 much more widely disseminated than has heretofore 
 been supposed. The discovery of gold in this condi- 
 tion and the ability to save it may have far-reaching 
 results in gold mining, especially as in talcose rocks 
 and serpentines much fine gold occurs as films of in- 
 finitesimal thinness, which increase the value of the 
 assays, but is exceedingly difficult to save in the mill. 
 In a piece of solid rock we have the material con- 
 trolled, no matter how fine it may be, and can detect 
 its presence by assay of even small samples, but unfor- 
 tunately we have no way of concentrating gravel so as 
 to get suitable assay samples except by laborious 
 processes, and may have to depend on working tests 
 for the detection of such gold. 
 
 Test for Fine Gold in Gravel. Probably the best ex- 
 perimental method would be to wash a large quantity 
 of gravel, previously measured, in the same water, 
 never allowing any of the latter to escape, but using 
 it over and over again, retaining only the finest sands 
 by a proper system of screens; and when a suitable 
 quantity of sands had been accumulated they might be 
 treated by the chlorination process, which dissolves 
 every trace of fine gold in the mass and saves 
 nearly all of it. The result obtained divided by the 
 number of yards of gravel concentrated would give the 
 average value per yard, and this might be greatly 
 
GOLD GRAVEL DEPOSITS. 297 
 
 more than shown by test workings in the sluice box. 
 The difference between the two results would be the 
 invisible gold. 
 
 All machines suitable for this class of work use 
 much less water per yard of gravel washed than is 
 necessary in hydraulic operations, and this is a most 
 important item if the deposits are so situated that 
 pumping mast be resorted to, as a good head of water 
 (pumped) will cost from 15 to 30 cents per miner's 
 inch according to the height to which it must be 
 raised, and the length of the pipe through which it 
 has to be forced, or the cost of labor and fuel. 
 
 Dry Washing. The difficulties attending the sepa- 
 ration of gold without the use of water, or as it is 
 called rather curiously, "dry washing," are enormous, 
 and it can only be attempted on the richest kind of 
 material with even a shadow of success. The great 
 mistake is made, as in so many other mining machines 
 and processes, originated by persons who as a usual 
 thing are totally ignorant of what has been attempted 
 by others before they became inoculated with the idea, 
 of supposing that the careful manipulation to which 
 the inventor subjects the small quantity of material on 
 which he operates can be repeated on a large scale in 
 actual mining. For success it is absolutely necessary 
 that the material should be absolutely dry and thor- 
 oughly pulverized, as any moisture, especially in clayey 
 soils, will prevent the grains of gold from separating 
 from the earthy matter. 
 
 Hydraulic Elevators. -Not a few localities in which 
 gold is found abundantly present difficulties due to 
 insufficient room below the deposit, on which we can 
 construct sluices of sufficient length to properly 
 wash the gravel, and in which we can deposit the 
 debris after it is washed. In such cases we are com- 
 pelled to resort to hydraulic elevators, by which the 
 gravel is lifted from 30 to 50 ft. or over and there 
 dumped into the sluice boxes, which can then be from 
 
29S PROSPECTING AND VALUING MINES. 
 
 one-eighth to a quarter of a mile longer than would 
 otherwise be possible. The method is of course only 
 available on moderately coarse material, as the diame- 
 ter of the tube and the force of the lifting jet prevent 
 the passage of very coarse material. 
 
 River Bars. These usually form at the junction of 
 two streams, or just below the point at which the cur- 
 rent is deflected from one side of the river to another. 
 If a stream is auriferous, these bars are often rich in 
 gold, which is brought down in flood time from the 
 upper country, often many miles. The Snake, Colum- 
 bia and Fraser Rivers are good examples of such 
 streams, in addition to the well known California 
 localities. On the Fraser, at Yale, the amount of fine 
 gold brought down by the stream, to localities not less 
 than 50 miles from the source of supply, is so great 
 that the surface of the pebbly bars, which act as riffles, 
 pays to work over annually; and a panful of moss 
 gathered from the bowlders exposed between high and 
 lo\v water mark, will show from fifty to several hun- 
 dred colors. It can easily be understood from this 
 that bars which have remained untouched for years 
 may therefore be very rich; immensely so in some in- 
 stances. Hill's bar, below "Yale, must have yielded 
 many dollars per cubic yard, when seven men with 
 three rockers took out $90,000 in 90 days. These bars 
 may be so near the level of the water, that it inter- 
 feres materially with working them. In such cases 
 Wing dams are resorted to. These structures 
 consist of a wall of brush and bowlders, built out in 
 the shallow water at some suitable point above the 
 ground to be worked, to divert the current and inclose 
 a block of desirable ground. The current is used to 
 run water wheels which pump the inclosure dry or 
 sufficiently so to enable the working of the gravel to 
 be successfully carried on. Such structures are of 
 course only available during a low stage of water, and 
 sudden flood is apt to wash them away, making 
 
GOLD GRA VEL DEPOSITS. 299 
 
 the operation risky, as a whole season's work, as well 
 as the money invested, may be lost in an hour. In 
 some few cases ifc may be possible to divert the stream, 
 which is a more satisfactory method if the ground 
 rendered available is sufficiently extensive to justify 
 the expense. Probably one of the most successful 
 enterprises of this kind was on the Cape claim near 
 Oroville, in California, the owners of which in early 
 days turned the Feather River into a flume 40 ft. 
 wide, and cleaned up from $600,000 to $700,000 in one 
 summer's work, although they lost the flume during a 
 sudden freshet before the job was completely finished. 
 
 Dredging the bed of the stream is sometimes 
 resorted to, it being reasonable to suppose, from all we 
 know of gravel mining, that if the bars in a river are 
 worth working, the gravel beneath the surface, which 
 we cannot see, must also contain gold in paying quan- 
 tities. Such dredges are in successful operation in 
 several localities, both in America and elsewhere. 
 Some machines can handle as much as 150 tons of 
 gravel an hour; but the quantity, as well as the suc- 
 cess of the dredge, will depend largely on the character 
 of the river bottom. If it is encumbered with large 
 bowlders, it may be impossible to work it to advan- 
 tage, and the best results will be obtained in moder- 
 ately fine material of a uniform character. 
 
 Adjustment of Saving Appliances to the Size of the 
 Gold. In any appliance for working gravel by 
 water, the measure of success will largely depend on 
 the careful adjustment of the amount of water used, 
 and the grade of the tables or sluice boxes, on or in 
 which the gravel is washed, to the size of the particles 
 of gold in the material under treatment; and the finer 
 and finer these become the more accurate must be the 
 adjustment. There are many localities where the entire 
 bulk of the gold is so fine that we have to resort to the 
 use of the principles involved in the undercurrent, or 
 to the use of amalgamated plates, or to a lining in the 
 
300 PROSPECTING AND VALUING MINES. 
 
 sluice box, made of inch boards bored full of holes, or 
 to blankets, burlaps, or rawhides with the hair point- 
 ing up stream, as in China; or to cocoanut matting 
 laid over a coarse linen cloth, as in New Zealand. The 
 localities where this kind of gold is chiefly found are 
 along the banks of large rivers and sea beaches, and 
 the gold is frequently accompanied by such large 
 quantities of "black sand" (consisting of magnetic 
 and titaniferous iron derived from the decay of granitic 
 rocks) that these, in any stream weak enough to save 
 the flaky gold, choke the saving appliances with a 
 solid bed of iron sand, through which it is impossible 
 for the gold to sink and reach the riffles or quick- 
 silvered surface below, and it is consequently passed on 
 through the sluices, on the top of the sand. The only 
 method of improving this state of affairs is to first 
 extract the iron sand, or that portion of it which is 
 magnetic, from the material under treatment, so that 
 the remainder may be finished in a much gentler cur- 
 rent than would be necessary to carry off the iron 
 sand, and yet sufficient for the task of separating the 
 quartz sands from the gold. Various appliances have 
 been designed to work these sands, but until recently 
 they have met with but a very limited share of suc- 
 cess. There appears, however, now to be a prospect, 
 by the use of magneto-electrical appliances, of making 
 more progress in the solution of the problem, which is 
 a fascinating one on account of the abundance and 
 widespread area of the material, and its constant 
 restoration by the operations of nature. 
 
 In working this class of material, the aim should be 
 to make the machinery as light and portable as possi- 
 ble, so that it may be readily moved to the material 
 instead of hauling the material to the machine, as this 
 rapidly becomes an expensive process, for while the 
 material may be abundant it is usually of no great 
 thickness at any one point. This is particularly the 
 case in beach sands, which may be scattered by heavy 
 
GOLD GRAVEL DEPOSITS. 301 
 
 storms and afterward reasserted by the gentler action 
 of the waves in more moderate weather, which pan out 
 the lighter particles of sand, leaving the gold and iron 
 in a concentrated form. 
 
 Throughout this chapter especial attention has been 
 paid to gold, but the same principles of prospecting 
 and working are equally applicable to all minerals 
 found in similar conditions, such as tin, platinum and 
 its allies, and even native silver as at Planchas de 
 Plata, in southern Arizona. These metals are, how- 
 ever, all worked in open air placers, and have not yet 
 been found, so far as the writer is aware, in paying 
 quantities in drift operations, though platinum and 
 iridosmine are found in nearly all the gravel diggings 
 of California, along with occasional diamonds. 
 
CHAPTER XVII. 
 WATER AND ITS MEASUREMENT. 
 
 WATER plays so important a part in all mining 
 operations that the available supply becomes a vital 
 question, whether for gold washing, for power or for 
 milling and domestic use. The following simple rules 
 for ascertaining the quantity and estimating the power 
 which can be derived from it will be found useful in 
 this connection. 
 
 Unit. Water may be measured by the gallon, the 
 cubic foot or the miner's inch, and the use of the 
 special term depends somewhat on the purpose to 
 which the water is to be applied; thus, city supplies 
 are usually estimated in gallons; irrigation quantities 
 in cubic feet or miner's inches, and for mining opera- 
 tions on a large scale almost universally in inches. 
 
 Weight. A cubic foot of fresh water, with the 
 barometer at 30 in., weighs, at 39 F., 62.423 Ib. ; 
 62.367 Ib. at 60; 62.218 Ib. at 90; and only 59.7 Ib. 
 at 212, a fair average being 62.33 Ib., but usually 
 called 62.51b. for convenience. Below 39 the weight 
 decreases, so that at 32, or the freezing point, it is 
 only 57.2 Ib. and its specific gravity only 0.9195. Sea 
 water weighs from 64.02 to 64.27 Ib. per cu. ft. 
 
 Bulk. 'A gallon of water U. S. standard contains 
 231 cu. in. This is equal to a cylinder 7 in. high by 
 6 in. in diameter, or to a cube 6.1358 in. on the edge, 
 and is 0.13368 of 1 cu. ft., so that 1 cu. ft. contains 7.48 
 gal., or in general terms 1\ gal. 
 
 Miner's Inch. This is the quantity of water which 
 
WATER AND ITS MEASUREMENT. 303 
 
 will flow through an orifice in a 1-in. board, 1 in. sq., 
 in 24 hours. In selling water, however, the water 
 companies sometimes make rates by the 10-hour and 
 12 hour in., users not requiring it for the full 24 hours. 
 The inch varies according to the pressure under which 
 it is discharged. The term arose in California in the 
 early days of gold mining, but the customs of differ- 
 ent camps varied, as the "head/* by which is meant 
 the distance from the top of the water to the center of 
 the hole, ranged from 4 to 7, or sometimes as much as 
 8 in. The 4-in. head is still used in the irrigation 
 districts of southern California, but the 6-in. head has 
 of late years been considered the standard in mining 
 estimates. Under a 4-in. head, through an orifice 1 
 in. sq., the discharge is equal to 1,728 cu. ft. or 12,- 
 925 gal. in 24 hours. The 6-in. head discharges 
 about 2,150 cu. ft., or 16,082 gal. in the same time. 
 The North Bloornfield reports, as the results of experi- 
 ments by Hamilton Smith, give 2,230 cu. ft. or 16.680 
 gal. The measurement is made by leading the water 
 into a tank, provided at a height of 2 in. from the bot- 
 tom with a horizontal slot of given dimensions, say 2 
 in., which can be closed by a moving bar, sliding in 
 it. If it is desired to measure all the water, this bar 
 is slid back until it allows the water to escape at such 
 a rate that the surface stands constantly at the re- 
 quired head, and the size of the aperture can be read 
 off immediately by graduations on the bar. If the 
 slot is 2 in. high and the bar has been slid back 60 in. 
 the flow will equal 2 X 60 = 120 in. If it is desired 
 to measure off a definite quantity the slot or gate is 
 properly adjusted, and the waste gate opened until the 
 requisite head is obtained in the measuring tank. 
 
 Pressure. Water exerts the same pressure in all 
 directions. In pipes the pressure is equal to the area 
 of the pipe in feet, multiplied by the vertical height 
 of the pipe (not by its length), and the quantity thus 
 Ascertained by 62^ lb, (the weight of 1 cu. ft. of 
 
304 
 
 PROSPECTING AND VALUING MINES. 
 
 water), or, if the area is calculated in inches, by 
 0.432292 of a pound (the weight of a column of water 
 1 in. sq. and 1 ft. high), and this by the height ver- 
 tically of the pipe in feet, the result will be the pres- 
 sure per inch in pounds. Moving water exerts less 
 pressure than when it is stationary, but when cut off 
 suddenly puts a greater strain on the pipe than the 
 simple stationary load, to which the momentum of the 
 moving column has been added. 
 
 The following table (condensed from Trautwine) 
 gives the weight of water, at 62 Ib. per cu. ft., con- 
 tained in 1 ft. of pipe of different diameters from 1 to 
 36 in. The fractions of inches are omitted, as seldom 
 us^d in mining operations. 
 
 WEIGHT OF WATER IN 1 FT. OF PIPE. 
 
 Diam. 
 in 
 Inches. 
 
 Weight, 
 Lb. 
 
 Diam. 
 in 
 
 Inches. 
 
 Weight, 
 Lb. 
 
 Diam. 
 in. 
 
 Inches. 
 
 Weight, 
 Lb. 
 
 Diam. 
 in 
 Inches. 
 
 Weight, 
 Lb. 
 
 1 
 
 0.33952 
 
 10 
 
 33.952 
 
 19 
 
 122.56 
 
 28 
 
 266.18 
 
 2 
 
 1.3581 
 
 11 
 
 41.082 
 
 20 
 
 135.81 
 
 29 
 
 285.53 
 
 3 
 
 3.0557 
 
 12 
 
 48.891 
 
 21 
 
 149.73 
 
 30 
 
 305.57 
 
 4 
 
 5.4323 
 
 13 
 
 57.379 
 
 22 
 
 164.33 
 
 31 
 
 326.27 
 
 5 
 
 8.4880 
 
 14 
 
 66.545 
 
 23 
 
 179.60 
 
 32 
 
 347.66 
 
 6 
 
 12.223 
 
 15 
 
 76.392 
 
 24 
 
 195.56 
 
 33 
 
 369.74 
 
 7 
 
 16.636 
 
 16 
 
 86.916 
 
 25 
 
 212.20 
 
 34 
 
 392.48 
 
 8 
 
 21.729 
 
 17 
 
 98.121 
 
 26 
 
 229.51 
 
 35 
 
 415.90 
 
 9 
 
 27.501 
 
 18 
 
 110.000 
 
 27 
 
 247.51 
 
 36 
 
 440.00 
 
 The quantities increase as the squares of the diame- 
 ter of the pipes. Thus a 36-in. pipe contains four 
 times as much as one 18 in. in diameter 440 to 110. 
 
 Discharge Under Head. The discharge of a pipe 
 from the bottom of a reservoir is found by multiply- 
 ing the area of the orifice by the velocity of the 
 stream, which depends upon the head or pressure. If 
 the opening is circular multiply the square of the 
 diameter in feet or inches by 0.7854, and this will be 
 the area in feet or inches. The velocity of discharge is 
 ascertained by multiplying the square root of the 
 bead in feet by 8,03, and the result will be the veloc- 
 
WATER AND ITS MEASUREMENT. 
 
 305 
 
 ity in feet per second. The following table (con- 
 densed from Trautwine) gives the velocity of dis- 
 charge in feet per second for heads of from 50 to 500 
 ft. Intermediate heads can be made proportional to 
 the nearest figures: 
 
 VELOCITY OF DISCHARGE UNDER DIFFERENT HEADS. 
 
 Head. 
 
 Velocity 
 Per Second. 
 
 Head. 
 
 Velocity 
 Per Second. 
 
 50 
 
 56.7 
 
 125 
 
 89.7 
 
 55 
 
 59.5 
 
 150 
 
 98.3 
 
 60 
 
 62.1 
 
 175 
 
 106.0 
 
 65 
 
 64.7 
 
 200 
 
 114.0 
 
 70 
 
 67.1 
 
 225 
 
 120.0 
 
 75 
 
 69.5 
 
 250 
 
 126.0 
 
 80 
 
 71.8 
 
 275 
 
 133.0 
 
 85 
 
 74.0 
 
 300 
 
 139.0 
 
 90 
 
 76.1 
 
 350 
 
 150.0 
 
 95 
 
 78.2 
 
 400 
 
 160.0 
 
 100 
 
 80.3 
 
 500 
 
 179.0 
 
 Power of Falling Water, (on the assumption that 
 one horse power is equal to 33,000 Ib. raised 1 ft. per 
 minute). Multiply together the number of cubic feet 
 of water which fall per minute; the vertical height of 
 the fall or head in feet; and the number 62.3 (the 
 weight of 1 cu. ft. of water in pounds) ; and divide the 
 result by 33,000. Thus 800 cu. ft. of water falling 16 
 ft. would give a theoretical horse power of 24.17. But 
 water wheels do not realize all this power. Undershot 
 wheels only realize from one-quarter to one-third; 
 breast wheels about one-half; overshots, from two- 
 thirds to three-quarters; turbines and wheels of the 
 Pelton type from three-quarters to 85%. In general 
 terms large quantities of water under small heads are 
 best utilized by turbines; but above 20-ft. heads the 
 impact wheel will be found satisfactory even up to 
 pressures of 2,000 ft. The makers of the Pelton wheel 
 issue a circular giving useful data in relation to the 
 measurement and use of water, and from it the follow- 
 ing tables are extracted. The first gives the b. p. of 
 
306 
 
 PROSPECTING- AND VALUING MINES. 
 
 1 in. of water under heads from 1 up to 1,100 ft. 
 This inch equals 1| cu. ft. per minute. The table 
 assumes 85% efficiency. 
 
 TABLE FOR CALCULATING HORSE POWER. 
 
 Heads 
 in Ft. 
 
 Horse 
 Power. 
 
 Heads 
 in Ft. 
 
 Horse 
 Power. 
 
 Heads 
 in Ft. 
 
 Horse 
 Power. 
 
 Heads 
 in Ft. 
 
 Horse 
 Power. 
 
 1 
 
 0.0024147 
 
 320 
 
 0.772704 
 
 170 
 
 0.410499 
 
 480 
 
 .159056 
 
 20 
 
 0.0482294 
 
 330 
 
 0.796851 
 
 180 
 
 0.434646 
 
 490 
 
 .183206 
 
 30 
 
 0.072441 
 
 340 
 
 0.820998 
 
 190 
 
 0.458793 
 
 500 
 
 .207-350 
 
 40 
 
 0.096588 
 
 350 
 
 0.845145 
 
 200 
 
 0.482940 
 
 520 
 
 .255644 
 
 50 
 
 0.120735 
 
 360 
 
 0.869292 
 
 210 
 
 0.5071/87 
 
 540 
 
 .303938 
 
 60 
 
 0.144882 
 
 370 
 
 0.893439 
 
 220 
 
 0.531234 
 
 560 
 
 .352232 
 
 70 
 
 C. 169029 
 
 380 
 
 0.917586 
 
 230 
 
 0.555381 
 
 580 
 
 .400526 
 
 80 
 
 0.193176 
 
 390 
 
 0.941733 
 
 240 
 
 0.579528 
 
 600 
 
 .448820 
 
 90 
 
 0.217323 
 
 400 
 
 0.965880 
 
 250 
 
 0.603675 
 
 650 
 
 .569555 
 
 100 
 
 0.24147'0 
 
 410 
 
 0.990027 
 
 260 
 
 0.627822 
 
 700 
 
 .690290 
 
 110 
 
 0.265617 
 
 420 
 
 .014174 
 
 270 
 
 0.651969 
 
 750 
 
 .811025 
 
 120 
 
 0.289764 
 
 430 
 
 .038321 
 
 280 
 
 0.676116 
 
 800 
 
 1.931760 
 
 130 
 
 0.313911 
 
 440 
 
 .062468 
 
 290 
 
 0.700263 
 
 900 
 
 2.173230 
 
 140 
 
 0.338058 
 
 450 
 
 .086615 
 
 300 
 
 0.724410 
 
 1000 
 
 2.414700 
 
 150 
 
 0.362205 
 
 460 
 
 .110762 
 
 310 
 
 0.748557 
 
 1100 
 
 2.656170 
 
 160 
 
 0.386352 
 
 470 
 
 .134909 
 
 
 
 
 
 Measurement by Weirs. In general terms a weir 
 is any obstruction across a stream, as a dam, over 
 which all the water in the stream is compelled to flow, 
 or so much of it as may be desired, which can be 
 regulated by suitable waste gates, which will maintain 
 a constant depth on the weir. Select a place in the 
 stream, where on being dammed a pond will be formed 
 of sufficient length to check the velocity of the stream. 
 Across the lower end of this spot place a board or 
 plank, in which a square notch has been previously 
 cut through which the water must flow. The length 
 of the notch in the dam should be from two to four 
 times its depth for small quantities of water, and 
 longer for large quantities. The edges of the notch 
 should be beveled toward the intake or upper side, 
 and the clear fall below the notch should be not less 
 than twice the depth, that is 12 in. if the notch is 6 
 in. deep, and so on, to prevent loss by back water. In 
 the pond, from 3 to 6 ft, above the dam, according as 
 
WATER AND ITS MEASUREMENT. 
 
 30? 
 
 the stream is small or large, drive a stake, and then 
 obstruct the water until it rises precisely to the bot- 
 tom of the notch (which must be level) and mark the 
 stake at this level. Then complete the dam so as to 
 cause all the water to flow through the notch, and 
 after allowing time for the water to settle, mark the 
 stake again for this new level. If preferred the stake 
 can be driven with its top precisely level with the 
 bottom of the notch and the depth of water be measured 
 with a rule after the water is flowing freely through 
 the notch, but the marks are preferable in most cases. 
 The distance between the marks is the theoretical 
 depth of flow corresponding to the depth in the table, 
 where an example is given of the method of making 
 the calculation. The quantity thus obtained can be 
 converted into gallons or miner's inches as desired. 
 
 The following table will save trouble in making com- 
 putations from weir measurements : 
 
 TABLE FOR WEIR MEASUREMENT. 
 
 Giving cubic feet of water per minute that will flow over a weir 1 in. wide 
 and from y% to 20% in. deep. 
 
 Inches. 
 
 M 
 
 M 
 
 % 
 
 Yz 
 
 % 
 
 H 
 
 % 
 
 
 
 .00 
 .40 
 1.13 
 2.07 
 3.20 
 4.47 
 5.87 
 7.40 
 9.05 
 10.80 
 12.64 
 14.59 
 16.62 
 18.74 
 20.95 
 23.23 
 25.60 
 28.03 
 30.54 
 33.12 
 35,77 
 
 .01 
 .47 
 1.23 
 2.21 
 3.35 
 4.64 
 6.06 
 7.60 
 9.26 
 11.02 
 12.88 
 14.84 
 16. 83 
 19.01 
 21.23 
 23.52 
 25.90 
 28.34 
 30.86 
 33.45 
 36.11 
 
 .05 
 .55 
 1.35 
 2.34 
 3.50 
 4.81 
 6.25 
 7.80 
 9.47 
 11.25 
 13.12 
 15.09 
 17.15 
 19.29 
 21.51 
 23.82 
 26.20 
 28.65 
 31.18 
 33.78 
 36.45 
 
 .09 
 .64 
 1.46 
 2.48 
 3.66 
 4.98 
 6.44 
 8.01 
 9.69 
 11.48 
 13.36 
 15.34 
 17.41 
 19.56 
 21.80 
 24.11 
 26.50 
 28.97 
 31.50 
 34.11 
 36.78 
 
 .14 
 .73 
 
 1.58 
 2.61 
 3.81 
 5.15 
 6.62 
 8.21 
 9.91 
 11.71 
 13.60 
 15.59 
 17.67 
 19.84 
 22.08 
 24.40 
 26.80 
 29.28 
 31.82 
 34.44 
 37.12 
 
 .19 
 .82 
 1.70 
 2.76 
 3.97 
 5.33 
 6.82 
 8.42 
 10.13 
 11.94 
 13.85 
 15.85 
 17.94 
 20.11 
 22.37 
 24.70 
 27.11 
 29.59 
 32.15 
 34.77 
 37.46 
 
 .26 
 .92 
 1.82 
 2.90 
 4.14 
 5.51 
 7.01 
 8.63 
 10.35 
 12.17 
 14.09 
 16.11 
 18.21 
 20.39 
 22.65 
 25.00 
 27.42 
 29.91 
 32.47 
 35.10 
 37.80 
 
 .32 
 
 1.02 
 1.95 
 3.05 
 4.30 
 5.69 
 7.21 
 8.83 
 10.57 
 12.41 
 14.34 
 16.36 
 18.47 
 20.67 
 22.94 
 25.30 
 27.72 
 30.22 
 32.80 
 35.44 
 38.15 
 
 1 
 
 2 
 
 3 
 
 4 
 
 5........ 
 
 6 
 
 7 ,. 
 
 g 
 
 9 
 
 10 
 
 11 
 12 
 
 13 
 
 14 .. 
 
 15 
 
 16. 
 
 17 
 
 18 
 
 19 
 
 20 
 
 
308 PROSPECTING AND VALUING MINES. 
 
 Suppose the weir to be 66 in. long, and the depth of 
 water on it to be 11| in. Follow down the left hand 
 column of the figures in the table until you come to 11 
 in. Then run across the table on a line with the 11, 
 until under f on top line and you will find 15.85. 
 This multiplied by 66, the length of weir, gives 
 1046.10, the number of cubic feet of water passing 
 per minute. 
 
 Measurement in an Open Stream by Velocity and 
 Cross Section. Measure the depth of the water at 
 from 6 to 12 points across the stream at equal dis- 
 tances between. Add all the depths in feet together 
 and divide by the number of measurements made; 
 this will be the average depth of the stream, which 
 multiplied by its width will give its area or cross 
 section. Multiply this by the velocity of the stream 
 in feet per minute, and you will have the cubic feet 
 per minute of the stream. 
 
 The velocity of the stream can be found by laying 
 off 100 ft. on the bank and throwing a float into it at 
 the middle, noting the time passing over the 100 ft. 
 Do this a number of times and take the average. 
 Then dividing this distance by the time gives the 
 velocity in feet per minute at the surface. As the top 
 of the stream flows faster than the bottom or sides 
 the difference being about 8% it is better to measure 
 a distance of 120 ft. for float and reckon it as 100. 
 
 This method can also be applied to measurements of 
 water in flumes. The error will tend toward excess, 
 if the friction along the sides and bottom is not 
 allowed for. 
 
WATER AND ITS MEASUREMENT. 309 
 
 TABLE FOR MEASURING WATER BY MINER'S INCHES. 
 
 Length of Opening in 
 Inches. 
 
 Openings 2 Inches High. 
 
 Openings 4 Inches High. 
 
 Head to 
 Center 
 5 in. 
 
 Head to 
 Center 
 6 in. 
 
 Head to 
 Center 
 7 in. 
 
 Head to 
 Center 
 5 in. 
 
 Head to 
 Center 
 6 in. 
 
 Head to 
 Center 
 7 in. 
 
 4 . 
 
 Cu. Ft, 
 
 1.348 
 1.355 
 1.359 
 1 361 
 
 Cu. Ft. 
 1.473 
 1.480 
 1.484 
 1.485 
 1.487 
 1.488 
 1.489 
 1.489 
 1.490 
 1.490 
 1.490 
 1.490 
 1.491 
 1.491 
 1.492 
 1.493 
 1.493 
 1.493 
 1.493 
 1.493 
 1.494 
 
 Cu. Ft. 
 1.589 
 1.596 
 1.600 
 1.602 
 1.604 
 1.604 
 1.605 
 1.606 
 1.606 
 1.607 
 1.607 
 1.607 
 1.607 
 1.608 
 1.608 
 1.609 
 1.609 
 1.609 
 1.609 
 1.610 
 1.610 
 
 Cu. Ft. 
 1.320 
 1.336 
 1.344 
 1 349 
 1.352 
 1.354 
 1.356 
 1.357 
 1.359 
 1.359 
 1.360 
 1.361 
 1.361 
 1.362 
 1.363 
 1.364 
 1.365 
 1.365 
 1.366 
 1.366 
 1.366 
 
 Cu. Ft. 
 1.450 
 1.470 
 1.481 
 1.487 
 1.491 
 1.494 
 1.496 
 1.498 
 1.499 
 1.500 
 1.501 
 1.502 
 1.503 
 1.503 
 1.505 
 1.507 
 1.508 
 1.508 
 1.509 
 1.509 
 1.509 
 
 Cu. Ft. 
 
 1.570 
 1.595 
 .608 
 .615 
 .620 
 .623 
 .626 
 .628 
 1.630 
 1.631 
 1.632 
 1.633 
 1.634 
 1.635 
 1.637 
 1.639 
 1.640 
 1.641 
 1.641 
 1.641 
 1.642 
 
 6 
 
 8 
 
 10 
 
 12 
 
 1.363 
 1.364 
 1.365 
 1.365 
 1.365 
 1.366 
 1.366 
 1.366 
 1.367 
 1.367 
 1.367 
 1.368 
 1.368 
 1.368 
 1.368 
 1.369 
 1.369 
 
 14 
 
 16 
 
 18 
 
 20 
 
 22 
 
 24 
 
 26 
 
 28 
 
 30 
 
 40 
 
 50 
 
 60 
 
 70 
 
 80 
 
 90 
 
 100 . . . . , 
 
 
CHAPTER XVIII. 
 
 ARTESIAN WELLS. 
 
 Definition. Strictly speaking, an artesian well 
 should flow naturally over the top of the pipe without 
 pumping. The name is very frequently but erro- 
 neously applied to any bored well, but such wells merely 
 differ from any ordinary well in the size of the hole 
 and the method of lining it. 
 
 Theory. Artesian wells depend for their success on 
 the property of water finding its own level, or the 
 tendency to stand at the same height in both the legs 
 of a tube bent into the shape of a U. We must there- 
 fore have for the source of water a region higher than 
 the one where the well is to be sunk, and even then, 
 owing to the friction in the ground and tube, the 
 water will not rise quite to this level. 
 
 Basin Wells. To secure the best results we must 
 have a saucer-shaped basin of strata all dipping 
 toward the center, and no part of the rim of the basin 
 must be lower than the point at which the well is sunk 
 (except as hereafter explained); and this basin must 
 be filled with alternating layers or strata of material 
 which will allow the ready flow of water, such as 
 gravel; and others, such as clay, which will not per- 
 mit its passage. Such a condition of the strata is 
 shown in pi. 14, fig. 8. To make it more intelligible 
 the vertical heights are made out of proportion to the 
 horizontal, but this does not affect the principle. 
 
 We have here three beds of clay, c,b,d, and two 
 
ARTKSIAN WELLS. 311 
 
 beds of gravel g and e, with surface dirt a. Now if a 
 well be sunk at the center of the basin, as at w, it 
 would penetrate all these beds. The upper bed of 
 clay c would hold water, and if the well did not go 
 through it we should have only an ordinary well. 
 But as the stratum of clay c would prevent any water 
 which fell on the surface exposure of the gravel g 
 from reaching the surface again, this bed would form 
 a reservoir in which the permanent water level would 
 be the height of its lower outlet If then we extend 
 the well into the gravel g we should make a lower 
 opening and the pressure in the underground reservoir 
 would force the water up the well, and perhaps over 
 the top. But if we extend the well through g and the 
 clay b into the gravel e we shall have tapped a larger 
 reservoir, the gravel being thicker, with a larger sur- 
 face exposure at a greater height, and the increased 
 pressure will cause the water to rise above the top of 
 the well, giving a permanent flow without pumping. 
 This is a true artesian well. 
 
 It might however happen, as in pi. 14, fig. 9, that 
 a portion of the strata had been cut away and subse- 
 quently overlaid by horizontal deposits as at c, but if 
 these should be a retentive clay, the result would be 
 the same, as the lower edges of the gravel g lying be- 
 tween the beds of clay a t b y would be hermetically 
 sealed by the clay c, and the well w would still be 
 artesian on account of the pressure resulting from the 
 altitude of a and b. 
 
 From the foregoing it will be seen that the best 
 results will be obtained in. those wells which are near- 
 est the center of the basin. These will be under 
 greater pressure than those nearer the rim of the 
 basin, and the flow will gradually diminish as it is ap- 
 proached, until those nearest to it, penetrating the 
 retaining clay higher than the natural outlet, will have 
 no overflow and become pumping wells. The central 
 wells will, however, be more expensive to put down. 
 
312 PROSPECTING AND VALUING MINES. 
 
 Exceptional Cases. Otber causes, however, than the 
 occurrence of saucer-shaped basins may give rise to 
 favorable conditions for artesian wells, as in the case 
 of San Bernardino in Southern California, which lies 
 a few miles north of Colton. All the wells in the 
 latter town are supplied with windmills, while in San 
 Bernardino there are upward of 800 artesian wells, 
 furnishing an immense flow of water. The quantity is 
 so great that large irrigating ditches are supplied 
 from this source. The boundary line between the two 
 regions is a nearly straight line running west of north. 
 Along this line there has been an immense fault across 
 the wide valley of the San Gabriel River, with its alter- 
 nating beds of clay and gravel, which has raised the 
 solid rock on the west, until it acts as a retaining 
 dam, converting the valley to the eastward into a huge 
 underground reservoir, very much as in pi. 11, fig. 4, 
 where AB may represent the fault, forming the reser- 
 voir P, so that while wells to the left of A would re- 
 quire windmills those at C might be artesian. (The 
 illustration is drawn for a different purpose, but the 
 relative position of the rocks and gravel beds is the 
 same.) Here the water finds its way into the up- 
 turned edges of the strata, bounded by the two walls 
 of the valley, and not being able to pass the barrier of 
 rock at the western end of the valley is forced to the 
 surface through any opening piercing the retaining 
 clays. That this is the case is proved by the wells 
 being deep close up to the break or fault instead of 
 encountering the retentive clays at gradually dimin- 
 ishing depths going westward. 
 
 Requisite Conditions. In the case just cited, the fault 
 haviDg become impermeable, or not affording an out- 
 let for the water, an artesian basin was formed where 
 none would otherwise have been possible, but it does 
 not always follow that because we have the proper 
 shaped basin it will furnish an artesian flow. If 
 the beds of clay are thin, very slight earthquake dis- 
 
ARTESIAN WELLS. 313 
 
 turbances may have broken them, so that they no 
 longer act as retaining walls, but allow the escape of 
 the water to other lower strata where it may be lost; 
 or the gravel beds may not be continuous over large 
 areas, but contained instead between two layers of clay 
 united all round like the crust of a pie over the fruit, 
 in which case there would be no pressure; and some- 
 times, when the flow is small, a deeper sinking in 
 search of a greater supply may allow the water to 
 escape into a lower stratum having a natural outlet, 
 and the flow be lost altogether. So many contin- 
 gencies surround the successful sinking of artesian 
 wells that only actual trial can determine the proba- 
 bility of success, except in cases where obviously 
 there can be no. extensive basin, as in broken moun- 
 tain countries. 
 
 The writer sunk 500 ft. in the San Joaquin Valley, 
 Cal., but never found water which came nearer the 
 top of the well than 12 ft., while further north, in 
 what would have been deemed a less favorable locality, 
 18 out of 19 wells were successful and the deepest 
 was less than 200 ft. 
 
 While gravel has been spoken of as the source of 
 water in the foregoing pages, it may be found in any 
 other porous rock which will easily permit its flow, 
 such as sand, sandstone, conglomerate, shale, chalk or 
 even limestone, the essential point being that what- 
 ever its nature it must lie between two non-permeable 
 strata of clay or rock. The retaining strata, instead 
 of clay, as assumed above, may be of any compact 
 rocks such as hard and unbroken slates, quartzite, 
 etc. Without these there can be no artesian well. 
 When such a bed is found in sinking, the operator 
 may expect satisfactory results, not otherwise; and if 
 water is found beneath it in reasonable quantity care 
 should be taken not to break the underlying one, for 
 the reasons already given. 
 
 If successful, artesian wells are invaluable for the 
 
314 PROSPECTING AND VALUING MINES. 
 
 water supply of cities and irrigation, as, though in 
 some cases their first cost may be large, it is not inva- 
 riably so, but on the contrary often quite moderate, 
 and the annual repairs are nominal. 
 
 Permanence of Supply. The well at Aire in Artois, 
 France, has given a stream rising 11 ft. above the sur- 
 face for the last 100 years, but in some cases where 
 the success of the experiment has induced the sinking 
 of a large number of wells in the same basin, the con- 
 sequent increase in the size of the outlet, combined 
 with excessive demands on the reservoir, has dimin- 
 ished the pressure and reduced the flow, as in the 
 London basin in England. Aside from such causes 
 there is little to fear except from destructive earth- 
 quakes which may rupture the strata, but fortunately 
 these are rare. 
 
 Examples. The following table of a few wells will 
 give some idea of the depths which have been attained 
 and show that there is no relationship between the 
 depth of the well and the quantity of water obtained. 
 In "Physical Data and Statistics of Calfornia," by W. 
 H. Hall, there are minute details of many hundreds of 
 wells varying in depth from 90 to over 1,000 ft., and 
 with bores ranging from 2 in. to 7 in. As is the case 
 elsewhere, many of the wells proved valueless for 
 either drinking purposes or for irrigation on account 
 of the large amount of mineral matter (chiefb 7 the 
 salts of sea water) which the water contains, the 
 amount running up to as much as 231 grains of solid 
 matter per gallon; but the general results have been 
 very satisfactory. The deepest bore reached a depth 
 of 2,160 ft. without finding artesian water. 
 
ARTESIAN WELLS. 
 SPECIMEN ARTESIAN WELLS AND BOREHOLES. 
 
 315 
 
 Locality. 
 
 Depth. 
 Ft. 
 
 Diameter 
 Inches. 
 
 Flow in 
 Gal. 
 24 Hours. 
 
 Height. 
 Ft. 
 
 Temper- 
 ature. 
 
 Grenelle, France .'. 
 Passy France 
 
 1798 
 1923 
 
 "*28" 
 
 864,000 
 5,582,000 
 
 54 
 
 82 
 82 
 
 Paris Basin France 
 
 300 to 400 
 
 2 8 
 
 
 
 
 London Basin 
 
 300 to 000 
 
 
 
 4 
 
 
 Chicago 
 
 700 to 1000 
 
 5 
 
 800000 
 
 
 
 Sperenberg Germany 
 
 4194 
 
 13 
 
 
 
 
 Louisville 
 
 2086 
 
 3 
 
 800 000 
 
 
 76^ 
 
 Bourne England 
 
 95 
 
 
 500000 
 
 40 
 
 
 Philadelphia 
 
 200 
 
 g 
 
 50 000 
 
 
 
 California 
 
 72 
 
 4 
 
 271 000 
 
 2 
 
 67 
 
 California 
 
 85 
 
 3 
 
 139,000 
 
 2 
 
 68 
 
 California <. 
 
 90 
 
 4 
 
 239 000 
 
 3 
 
 
 California 
 
 95 
 
 7 
 
 465 000 
 
 
 68 
 
 California . . . . 
 
 100 
 
 3 
 
 224 000 
 
 2V 
 
 
 California. . . . < 
 
 106 
 
 6 
 
 315,000 
 
 1 
 
 65Mj 
 
 California 
 
 123 
 
 3 
 
 164000 
 
 2 
 
 
 California 
 
 123 
 
 7 
 
 1,011,000 
 
 
 ;" 
 
 California 
 
 140 
 
 3 
 
 173 000 
 
 2 
 
 
 California 
 
 205 
 
 T 
 
 926 000 
 
 
 
 California 
 
 300 
 
 r~ 
 
 388000 
 
 7 
 
 64 
 
 
 
 
 
 
 
USEFUL TABLES. 
 
 ELEMENTS (CLARKE). 
 
 Name. 
 
 Sym- 
 bol. 
 
 Atom- 
 icity. 
 
 Atomic Weight. 
 
 Sp. Gr. 
 
 H=l. 
 
 O=-16. 
 
 
 Al 
 
 Sb 
 (?) 
 As 
 
 Ba 
 Bi 
 B 
 Br 
 Cd 
 Cs 
 Ca 
 
 C 
 
 Ce 
 Cl 
 Cr 
 Co 
 CborNb 
 
 Cu 
 
 Er 
 F 
 Gd 
 Ga 
 Ge 
 
 BeorGl 
 Au 
 He 
 
 H 
 In 
 I 
 
 IV. 
 V 
 
 (?) 
 V 
 
 II 
 
 V 
 
 III 
 I 
 II 
 I 
 II 
 
 IV 
 
 III 
 I 
 
 VI 
 IV 
 V 
 
 II 
 
 (?) 
 
 (?) 
 (?) 
 (?) 
 
 II 
 
 HI 
 (?) 
 I 
 III 
 I 
 
 26.91 
 119.52 
 (?) 
 74.44 
 
 136.39 
 206.54 
 10.86 
 79.34 
 111.10 
 131.89 
 39.76 
 
 11.91 
 
 138.30 
 35.18 
 51.74 
 58.55 
 93.02 
 
 63.12 
 
 165.06 
 18.91 
 155.57 
 69.38 
 71.93 
 
 9.01 
 195.74 
 (?) 
 1.000 
 112.99 
 125.89 
 
 27.11 
 120.43 
 
 (?) 
 75.01 
 
 137.43 
 208.11 
 10.95 
 79.95 
 111.95 
 132.89 
 40.07 
 
 12.00 
 
 139.35 
 35.45 
 52.14 
 58.99 
 93.73 
 
 63.60 
 
 166.32 
 19.06 
 156 76 
 
 2.502.81 
 1 6.626.86 
 ) 5.74 5.83 amorphous 
 (?) 
 ) 5.635.96 
 1 3.70 4.72 allotropic 
 3.75-4 
 9.67-10 
 2.532.68 
 2.95-3.19 
 7.99-8.69 
 1.87-1.89 
 1 55 1 80 
 
 AntimonyCstibni 1 m) 
 Argon 
 
 Arsenic 
 
 Barium 
 
 Bismuth 
 
 Boron 
 
 
 Cadmium 
 
 
 Calcium 
 
 
 f 3.33 3.55 diamond 
 I 1.842.5 graphite 
 1 1.76-2.10 charcoal 
 ^ 1.72-1.78 lampblack 
 6.63-6.73 
 1.33 liquefied 
 6.207.3 
 7.72-8.95 
 6-7.37 
 ( 8.398.96 
 < 8-8.2 allotropic 
 ( 7.27-8.22 molten 
 
 Cerium . . . . . 
 
 Chlorine 
 
 Chromium . < . . 
 
 Cobalt 
 
 Columbium (nio- 
 bium). 
 Copper (cuprum) . . 
 
 Fluorine 
 
 
 Gadolinium 
 
 
 Gallium 
 
 69.91 
 
 72.48 
 
 9.08 
 197.23 
 (?) 
 1.008 
 113.85 
 126.85 
 
 5.93-5.96 
 5.469 
 
 1.64-2.01 
 19.219.47 
 (?) 
 j .025-.033 liquefied 
 
 Germanium 
 
 Glucinum (berylli- 
 
 Gold (aurum) 
 Helium 
 
 
 Indium 
 
 ) .620 .628 occluded 
 7.117.42 
 j 4.82-5.02 solid 
 1 3.794 molten 
 
 Iodine 
 
 
USEFUL TABLES. 
 
 ELEMENTS (CLARKE). - Continued. 
 
 317 
 
 Name. 
 
 Sym- 
 bol. 
 
 Atom- 
 icity. 
 
 Atomic Weight. 
 
 Sp. Gr. 
 
 H=l. 
 
 O=16. 
 
 Iridiuin 
 
 Ir 
 Fe 
 
 La 
 Pb 
 
 Li 
 Mg 
 Mn 
 
 Hg 
 
 Mo 
 Nd 
 Ni 
 
 N 
 
 ds 
 
 
 Pd 
 Ph 
 
 Pt 
 
 K 
 Pr 
 Rh 
 Rb 
 Ru 
 Sm 
 Sc 
 Se 
 Si 
 
 Ag 
 
 Na 
 Sr 
 S 
 Ta 
 Te 
 Tr 
 Tl 
 Th 
 Tu 
 
 Sn 
 
 Ti 
 W 
 U 
 V 
 Yt 
 Y 
 Zn 
 Zr 
 
 IV 
 VI 
 
 in 
 
 IV 
 
 i 
 ii 
 
 VI 
 
 II 
 
 VI 
 
 
 
 V 
 VI 
 
 II 
 
 IV 
 V 
 
 IV 
 
 I 
 (?)] 
 
 IV 
 
 I 
 
 VI 
 
 (?) 
 Ill 
 
 VI 
 IV 
 
 I 
 
 I 
 II 
 
 VI 
 V 
 VI 
 
 (?) 
 Ill 
 
 IV 
 
 (?) 
 
 IV 
 
 IV 
 VI 
 VI 
 V 
 
 III 
 III 
 II 
 
 IV 
 
 191.66 
 55.60 
 
 137.59 
 205.36 
 
 6.97 
 24.10 
 54.57 
 
 198.49 
 
 95.26 
 139.70 
 58.24 
 13.93 
 189.55 
 15.88 
 105.56 
 30.79 
 
 193.41 
 
 38.82 
 142.50 
 102.23 
 84.78 
 100.91 
 149.13 
 43.78 
 78.42 
 28.18 
 
 107.11 
 
 22.38 
 86.95 
 
 31. as 
 
 181.45 
 126.52 
 158.80 
 202.61 
 230.87 
 169.40 
 
 118.15 
 
 47.79 
 183.43 
 237.77 
 50.99 
 171.88 
 88.35 
 64.91 
 89.72 
 
 193.12 
 56.02 
 
 138.64 
 206.92 
 
 7.03 
 
 24.28 
 54.99 
 
 200.00 
 
 95.99 
 140.80 
 58.69 
 14.04 
 190.99 
 16.00 
 106.36 
 31.02 
 
 194.89 
 
 39.11 
 143.60 
 10H.01 
 85.43 
 101.68 
 150.26 
 44.12 
 79.02 
 28.40 
 
 107.92 
 
 23.05 
 87.61 
 32.07 
 182.84 
 127.49 
 160.00 
 204.15 
 232.63 
 170 70 
 
 18 61 22 42 
 
 Iron (ferrum) 
 
 f 7.48-7.87 bar 
 1 7.13 reduced by C 
 \ 8.12 electrolytic 
 | 6.88 molten 
 i. 8.05 molten steel 
 6.05-6.16 
 ) 11.1611.50 
 } 10.3710.95 molten 
 5.78- 5.89 
 1.69- -2. 24 
 6.86 8.03 
 I 14. 15.19 solid 
 1 12.5713.61 liquid 
 8.498.64 
 
 Lanthanum 
 Lead (plumbum) . . . 
 Lithium 
 
 Magnesium 
 
 Manganese 
 
 Mercury (hydrar- 1 
 gyruin) ..... f 
 
 Molybdenum 
 
 Neody mium 
 Nickel 
 
 7,819.26 
 0.370.90 liquefied 
 21.422.477 
 0.581.24 liquefied 
 10.812.15 
 1.482.34 
 ( 19.5-21.8 
 -j 15.79-21. 15 spongy 
 J20.98-22.89precip. 
 .84 .87 [black 
 
 Nitrogen . . 
 
 Osmium 
 
 Oxygen 
 
 Palladium 
 
 Phos phorus 
 
 Platinum 
 
 Potassium (kalium) 
 Praseodymium 
 Rhodium 
 
 1112.1 
 1.52 
 1112.26 
 
 Rubidium 
 
 Ruthenium 
 
 
 Scandium 
 
 '"4.2-4.86"" 
 2-2.49 
 I 9.5510.62 
 J 9.12 10 molten 
 93 .98 
 2.40-2.58 
 1.46-2.09 
 10.0810.78 
 6.116.34 
 
 
 Silicon . 
 
 Silver (argentum). . 
 
 Sodium (natrium). . 
 Strontium 
 
 Sulphur 
 
 Tantalum 
 
 Tellurium 
 
 
 Thallium. 
 
 11.78-11.91 
 10.9711.23; 
 
 Thorium 
 
 Thulium . 
 
 Ti i (stannum) . . . 
 
 119.05 
 
 48.15 
 184.83 
 239.59 
 51.38 
 173.19 
 89.02 
 65.41 
 90.40 
 
 j 7.147.60 
 | 5.80 6.02 allotropic 
 
 16.619.26 
 18.2318.68 
 5.55.87 
 
 Titanium 
 Tungsten (wolfram) 
 Uranium , 
 
 Vanadium 
 
 Ytterbium . .- 
 
 Yttrium 
 
 
 Zinc 
 
 6.487.21 
 4.15 
 
 Zirconium 
 
 
318 PROSPECTING AND VALUING MINES. 
 
 The atomic weights here given have been compiled by Prof. F. W. Clarke 
 from the most recent and reliable determinations and are adopted as stand- 
 ard by the American Chemical Society. 
 
 In addition to the foregoing there are a number of supposed elements-- 
 actinium, holmium, idunium, ilmenium, mosaadrium, neptunium, phillippium 
 and decipium, not accepted as valid by all chemists. Argon and helium, 
 however, are placed in the list, though little is known about them. 
 
 The wide range in specific gravity is due to impurity of samples in some 
 cases; temperature when tested; with metals whether cast, rolled, ham- 
 mered, etc. ; and to the fact that the determinations were made by different 
 chemists using different methods. 
 
 In the older chemical nomenclature oxygen v as assumed as 16 to 1 of 
 hydrogen. Later determinations give 15.88 to 1. Consequently the values 
 of atomic weights are calculated on two scales, on one of which hydrogen is 
 taken as 1, and on the other, oxygen as 16. The differences are only 
 fractional. 
 
 GENERAL CLASSIFICATION OF MINERALS (BRUSH). 
 I. MINERALS WITH METALLIC OR SUB-METALLIC LUSTER. 
 
 NOTE. Minerals having metallic luster are opaque, and do not transmit 
 light even through their thinnest edges. The color of their powder, or their 
 streak, is therefore dark, though not necessarily black. The minerals with 
 sub-metallic luster which are included in this section all give dark-colored 
 streaks. Many dark-colored minerals whose luster is doultful have been 
 placed here, and also in Section II. 
 
 A. FUSIBLE PROM 1 TO 5 OR EASILY VOLATILE. 
 
 1. Arsenic Compounds. B. B. on charcoal give a volatile coating of arsenious 
 
 oxide. 
 
 2. Selenium Compounds. B. B on charcoal give a characteristic radish-like 
 
 odor and impart an azure-blue color to the reducing flame. 
 
 3. Tellurium Compounds. When treated in a test-tube with 5 cc. of concen 
 
 trated H 2 SO 4 and gently heated, the acid assumes a reddish-violet color. 
 
 4. Antimony Compounds. B. B. on charcoal give a dense white coating of 
 
 oxide of antimony. 
 
 5. Sulphides. When roasted in the open tube or on charcoal give the odor 
 
 of sulphurous anhydride, but do not give the reactions of the preceding 
 divisions. 
 
 6. Not belonging to the foregoing divisions. 
 
 B. INFUSIBLE, OR FUSIBLE ABOVE 5, AND NON-VOLATILE. 
 
 1. Iron Compounds. Become magnetic after heating B. B. in the reducing 
 
 flame. 
 
 2. Manganese Compounds. Impart to the borax bead in O, F. a reddish- 
 
 violet color. 
 
 3. Not belonging to the foregoing divisions. 
 
 II. MINERALS WITHOUT METALLIC LUSTER. 
 
 NOTE. Minerals without metallic luster are transparent, although they 
 may have such an intense color that they transmit light only through very 
 thin edges. The color of their powder, or their streak is generally white or 
 light-colored, never black. 
 
 A. EASILY VOLATILE, OR COMBUSTIBLE. 
 
 Eapidly disappear when heated B. B. on charcoal. 
 
USEFUL TABLES. 319 
 
 B. FUSIBLE FROM 1 TO 5, AND NON-VOLATILE, OR ONLY SLOWLY OR PARTIALLY 
 VOLATILE. 
 
 PART I. Give a Metallic Globule when fused with sodium carbonate on 
 
 charco 1. 
 J. Silver Compounds. B. B. with sodium carbonate on charcoal give a 
 
 globule of silver. 
 2 Lead Compounds. B. B. with sodium carbonate on charcoal give a globule 
 
 of lead. 
 
 3. Bismuth Compounds. B. B. with sodium carbonate on charcoal give a 
 
 globule of bismuth. 
 
 4. Antimony Compounds. B. B. with sodium carbonate on charcoal give a 
 
 globule of antimony. 
 
 5. Copper Compounds. B. B. with sodium carbonate on charcoal give a 
 
 globule of copper. The powdered mineral on charcoal, after moistening 
 with hydrochloric acid, imparts an azure-blue color to the blowpipe 
 flame. 
 
 PART II. Iron Compounds. Become magnetic after heating before the 
 blowpipe in the reducing flame. 
 
 1. Sulphates, Arsenides, and Phosphates, chiefly. Soluble in hydrochloric or 
 
 nitric acid without a perceptible residue, and without yielding gelatinous 
 silica upon evaporation. 
 
 2. Silicates. Soluble in hydrochloric or nitric acid, and yield gelatinous silica 
 
 upon evaporation, or decomposed with the separation of silica. 
 
 3. Not belonging to the foregoing divisions. Insoluble in hydrochloric acid. 
 
 PART III. When fused with sodium carbonate on charcoal do not give a 
 metallic globule, and when fused alone in the reducing flame do not 
 become magnetic. 
 
 1. Salts of the Alkali and Alkali-Earth Metals. After intense ignition be- 
 
 fore the blowpipe, either in the forceps or on charcoal, the ignited 
 material giv s an alkaline reaction when placed on moistened turmeric 
 paper. 
 
 a) Easily and completely soluble in water. 
 
 b) L soluble in water, or difficultly or only partially soluble. 
 
 2. Arsenates. Phosphates and Borates, chiefly. Soluble in hydrochloric 
 
 acid, but do not yield a jelly or a residue of silica upon evaporation. 
 
 3. Silcates. Soluble in hydrochloric acid, and yield gelatinous silica upon 
 
 evaporation. 
 
 a) In the closed tube give water. 
 
 b) In the closed tube give little or no water. 
 
 4. Silcates. Decomposed by hydrochloric acid with the separation of silica, 
 
 but without the formation of a jelly. 
 
 a) In the closed tube give water. 
 
 b) In the closed tube give little or no water. 
 
 5. Not belonging to the foregoing divisions. Insoluble in hydrochloric acid. 
 
 C. INFUSIBLE, OR FUSIBLE ABOVE 5. 
 
 1. Salts of the Alkali-Earth Metals. After intense ignition before the blow- 
 
 pipe, either in the forceps or on charcoal, the ignited material gives an 
 alkaline reaction when placed on moistened turmeric paper. 
 
 2. Carbonates. Sulphates, Oxides, Hydroxides and Phosphates, chiefly. 
 
 Soluble in hydrochloric acid, but do not yield a jelly or residue of silica 
 upon evaporation. 
 
 3. Silicates. Soluble in hydrochloric acid, and yield gelatinous silica upon 
 
 evaporation. 
 
 4. Silicates. Decomposed by hydrochloric acid with the separation of silica, 
 
 but without the formation of a jelly., 
 
320 PROSPECTING AND VALUING MINES. 
 
 5. Not belonging to the foregoing divisions. Insoluble in hydrochloric acid. 
 
 a) Hardness less than that of glass or a good quality of steel. Can 
 
 be scratched by a knife. 
 
 b) Hardness equal to or greater than that of glass. Cannot be 
 
 scratched by a knife. 
 
 CHARACTERS OF MINERALS (DANA). 
 
 1. Name, synonyms. 
 
 2. Crystalline, form and structure. 
 
 System of crystallization. 
 
 Axial ratio and angular elements. 
 
 Twinning 
 
 General structure, amorphous varieties, initiative forms, etc. 
 
 3. Physical characters : 
 
 Cohesion, Cleavage, Fracture, Hardness. 
 
 4. Characters relating to 
 
 Heat, 
 
 Electricity, 
 
 Magnetism. 
 
 5. Taste and odor. 
 
 6. Chemical composition. 
 
 7. Pyrognostic qualities (blowpipe). 
 
 SYSTEMS OF CRYSTALLIZATION (DANA). 
 
 I. Isometric 3 equal axes, at right angles to each other. (Ex. cube, octa- 
 
 hedron , dodecahed ron = py rite). 
 
 II. Tetragonal 3 axes. The 2 lateral axes equal, the vertical axis longer or 
 
 shorter: all at right angles to each other. 
 
 III. Hexagonal and Rhombohedral, 4 axes; 3 lateral axes in same plane at 
 
 60 from each other and a fourth vertical axis at right angles to them 
 and either longer or shorter. 
 
 In the Hexagonal system proper there are 4 principal planes of 
 symmetry; 3 equal planes intersecting at 60, and a fourth unequal, 
 normal to them ; also 3 auxiliary planes diagonal to the first set (ex- 
 ample, apatiie group). 
 
 The Rhpmboheclral system includes forms with only 3 planes of 
 symmetry intersecting at 12u in the vertical axis. (Ex. rhombohe- 
 dron many forms of calcite and tourmaline). 
 
 IV. Orthorhombic 3 unequal axes at right angles to each othe-; 3 planes 
 
 of symmetry, which intersect in these axes but are all different. 
 
 V. Monoclinic 3 unequal axes, of which one lateral axis is inclined to the 
 
 vertical axis, the other angles right angles; 1 plane of symmetry. 
 
 VI. Triclinic 3 unequal axes, and their intersections are all oblique. 
 
 MINERAL CHARACTERS DEPENDING UPON 'LIGHT (DANA). 
 Kinds of Luster : 
 
 1. Metallic; sub-metallic. 
 
 2. Adamantine (like diamond). 
 
 3. Vitreous (like broken glass). 
 
 4. Resinous (like yellow resinj. 
 
 5. Greasy (like elaeolite). 
 
 6. Pearly. 
 
 7. Silky (the result of a fibrous structure). 
 
USEFUL TABLES. 321 
 
 Degrees of Intensity : 
 
 1. Splendent. 
 
 2. Shining. 
 
 3. Glistening. 
 
 4. Glimmering. 
 
 INDIVIDUALIZATION OF CRYSTALS (CROSBY). 
 
 I. Distinct, separate and so nearly perfect minerals that their proper forms 
 
 may be clearly recognized^ crystallized. 
 
 II. Confused mass showing crystal faces or planes and cleavage planes. 
 
 but no perfect crystals (rock salt and white marble) crystalline or 
 massive. 
 
 III. Crystalline form and cleavage both entirely wanting to the unaided 
 
 eye, but the specimen shows double refraction when a thin section is 
 viewed by polarized light (chalcedony)=cryptocrystalline or com- 
 pact. 
 
 IV. Entirely devoid of crystallization (opal and obsidian) amorphous. 
 Implanted crystals =crystals of uniform size thickly set on a surface. 
 Drusy=very small implanted crystals. 
 
 INTERNAL STRUCTURE OF MINERALS (CROSBY). 
 
 Granular Fine to coarse = in grains. 
 
 Compact or impalpable=when the grains are invisible to the naked eye. 
 
 Glassy or vitreous=no trace of granular structure even under microscope; 
 
 may be crystalline (like vitreous quartz) or amorphous (like obsidian). 
 Lammellar= lamination independent of crystallization, or dependent. In the 
 
 first case called b ;nded; in the second, foliated. 
 Fibrous=if coarse, called columnar or baaded. 
 
 EXTERNAL FORMS OF MINERALS (CROSBY). 
 
 Botryoidal=rounded, grapelike. 
 
 Mammillary= larger rounded prominences. 
 
 Stalactitic= deposited from solution by dripping water from overhanging 
 rock. 
 
 Stalagmitic^Deposited from solution by dripping water on floor of caves, etc. 
 
 Tufaceous porous deposits formed when reeds, grasses, moss, etc., are in- 
 crusted by mineral solutions. 
 
 Concretionary = rounded mass or nodule produced by aggregations of min- 
 eral matter in the body of a rock. 
 
 Pisolitic if the concretions are small (about size of peas). 
 
 Oolitic = if very small (fish roe or mustard seed). 
 
 Geodes=hollow concretions. 
 
 Amydaloids almond shaped, deposited in the vesicles or steamholes of lava 
 
 Dendritic, arborescent, mossy = (stains of iron and manganese, native copper, 
 etc.), resembling vegetation. 
 
 Reticulated. = net-like. 
 
 Plumose feather-like. 
 
 Filiform wire or thread-like. 
 
 Acicular=like needles. 
 
 FRACTURE (CROSBY). 
 Conchoidal = shelly. 
 Even. 
 Uneven. 
 
 Earthy (like clay or chalk). 
 Hackly. 
 Splintery. 
 
322 PROSPECTING AND VALUING MINES. 
 
 SCALE OF FUSIBILITY OF MINERALS (VON KOBELL). 
 
 1. Stibnite (antimony glance), large fragments are fusible in the ordinary 
 
 flame of a candle. 
 
 2. Natrolite; fine needles are fusible in the flame of a candle; large frag- 
 
 ments fuse to a globule B.B. 
 
 3. Almandite (alumina-iron garnet); infusible in the flame of a candle; can be 
 
 fused to a globule B.B. if in small fragments. 
 
 4. Actinolite (var. amphibolite): fusible to a globule in fine splinters B.B. 
 
 5. Orthoclase: in very fine splinters is still fusible to an irregular globule; if 
 
 in larger fragments only the edges are rounded B. B. 
 
 6. Bronzite (diallage); only the finest edges or points can be rounded B.B. 
 
 To these Crosby adds : 
 
 7. Quartz; infusible alone, B.B. 
 
 THE GEOLOGIC SERIES, ACCORDING TO LE CONTE. 
 
 Eras. 
 
 Ages. 
 
 Periods. 
 
 Epochs. 
 
 5. Psychozoic . . 
 
 7. Age of Man. 
 
 Human. 23. 
 
 Recent. 
 
 4. Cenozoic... 
 
 6 . Age of Mamm als . . 
 
 f Quaternary 22 
 
 ( Terrace. 
 < Cham plain. 
 ( Glacial. 
 ( Pliocene. 
 < Miocene. 
 ( Eocene. 
 
 j 
 [.Tertiary 21 
 
 
 3. Mesozoic . . . 
 
 5. Age of Reptiles 
 
 ( Cretaceous ... 20 
 
 
 -< Jurassic 19 
 ( Triassic 18 
 
 
 Upper. 
 2. Palaeozoic... 
 
 Lower. 
 
 CARBONIFEROUS 
 
 4. Age of Acrogens 
 and Amphibians. 
 
 ( Permian 17 
 
 
 -\ Carboniferous 16 
 ( Sub-carboniferous. 15 
 
 DEVONIAN. 
 
 3. Age of Fishes 
 
 ( Chemung . . . 14 
 
 
 J Hamilton 13 
 
 1 Corniferous 12 
 LOriskany 11 
 
 
 SILURIAN. 
 
 2. Age of Invertebrates 
 
 CAMBRIAN. 
 
 f Helderberg . . .10 
 
 
 Salina 9 
 
 Niagara . 8 
 
 Trenton 7 
 
 [ Canadian 6 
 
 
 ( DikelocephaPs zone 5 
 < Paradoxides zone. . 4 
 f Olenellus zone 3 
 
 
 1 . Archaean or 
 Archaezoic 
 
 1 Archaean 
 
 \ Huronian 2 
 
 
 
 / Laurentian 1 
 
USEFUL TABLES* 
 
 323 
 
 THE GEOLOGIC SERIES, ACCORDING TO DANA. 
 [See also p. 68 for the system adopted by the U. S. Geological Survey.] 
 
 Age of Man, or Quaternary. 
 
 Mammalian Age. 
 
 Tertiary Period. 
 
 Reptilian Age. 
 
 Cretaceous. 
 
 
 Jurassic. 
 
 Wealden (epoch). 
 
 Oolitic (epoch). 
 
 Liassic (epoch). 
 
 Triassic. 
 
 
 Carboniferous Age. 
 
 Permian. 
 
 Carboniferous. 
 
 Sub-carboniferous. 
 
 Devonian Age, 
 or Age of Fishes. 
 
 Catskill. 
 
 Chemung. 
 
 Hamilton. 
 
 Corniferous. 
 
 Silurian Age, or 
 Age of Inverte- 
 brates. 
 
 Upper Siluria-i. 
 
 Oriskany. 
 
 Lower Helderberg. 
 
 Salina. 
 
 Niagara. 
 
 Lower Silurian. 
 
 Trenton. 
 
 Canadian. 
 
 Primordial, or Cambrian. 
 
 Below the Lower Silurian come the azoic schists and granite. 
 
324 
 
 PROSPECTING AND VALUING MINES. 
 
 CLASSIFICATION OF ROCKS. 
 A. Igneous Rocks. B. Aqueous and 
 IGNEOUS 
 
 Glassy. 
 
 Acid Glasses. 
 Obsidian, Perlite, Pumice, 
 Pitchstone. 
 
 
 Chief Feldspar Orthoclsae. 
 
 Chief Feldspar 
 
 Biotite (or) (and) Hornblende 
 (or) (and) Auglite. 
 
 Biotite (or) (and) 
 Hornblende. 
 
 
 +Quartz. 
 
 Quartz. 
 
 Nepheline 
 or Leucite. 
 
 +Quartz. 
 
 Quartz. 
 
 TRACHYTE GROUP. 
 
 ANDESITE GROUP. 
 
 Felsitic 
 and 
 
 Rhyolite. 
 
 Trachyte. 
 
 Phonolite 
 (rare). 
 
 Dacite. 
 
 Andesite. 
 
 Porphyritic. 
 
 (Quartz 
 Porphyry.) 
 
 (Prophyry.) 
 
 Leucite 
 Phonolite 
 (very rare). 
 
 (Porphy- 
 rite.) 
 
 (Porphy- 
 rite.) 
 
 
 (Quartz 
 Felsite.) 
 
 (Felsite.) 
 
 
 
 
 Fragmental. 
 
 Rhyolite 
 Tuff and 
 Breccia. 
 
 Trachyte 
 Tuff and 
 Breccia. 
 
 Phonolite 
 Tuff and 
 Breccia. 
 
 Andesitic Tuff 
 and Breccia. 
 
 
 GRANITE GROUP. 
 
 
 DIORITE GROUP. 
 
 Granitoid. 
 
 Granite 
 (Pegmatite) 
 
 Syenite 
 (rare). 
 
 Nepheline- 
 Syenite 
 (rare). 
 
 Leucite- 
 Syenite 
 (very rare). 
 
 guartz- 
 iorite 
 (Tonalite). 
 
 Diorite. 
 
 Si0 3 . 
 
 80.65# 
 
 65.55# 
 
 60.50# 
 
 70.60# 
 
 65.05$ 
 
USEFUL TABLES. 
 
 325 
 
 ACCORDING TO PROF, J. F. KEMP. 
 ^Eolian Rocks. C. Metamorphic Rocks. 
 ROCKS). 
 
 Andesite Obsidian. 
 
 Basic Glasses, 
 
 Scorias, Tachylite, 
 
 Basic Obsidian. 
 
 Plagioclase. 
 
 Nepheline, 
 Leucite. 
 
 No Feldspar. 
 
 Pyroxenes. 
 
 A Series of 
 Rare Basaltic 
 Rocks. 
 
 Augite (or) (and) 
 Hornblende 
 (or) (and) Biotite. 
 
 ~ Olivine. 
 
 +Olivine. 
 
 Olivine. 
 
 -fOlivine. 
 
 Augite- 
 Andesite. 
 
 Oli vine- 
 free 
 Basalt. 
 
 (Diabase.) 
 
 Basalt. 
 
 Dolerite. 
 
 (Oli vine- 
 Diabase.) 
 
 With Nephel- 
 ine, Leucite 
 ( eldom Meilite) 
 one or all. 
 
 Not readily 
 
 distinguishable 
 
 from Basalt 
 
 without the 
 
 microscope. 
 
 Extremely rare 
 
 in America. 
 
 Augitite. 
 
 Limburgite 
 
 Not readily distinguish 
 able from Bas lit. 
 
 Extremely 
 rare in America. 
 
 Basaltic Tuffs and Breccias. 
 
 GABBRO GROUP. 
 
 
 Diabase. 
 Gabbro. 
 
 Anortho- 
 site. 
 
 Olivine- 
 Diabase. 
 
 Olivine- 
 Gabbro. 
 
 Theralite 
 (extremely 
 rare). 
 
 Pyroxen- 
 ite. 
 
 Peridotite. 
 
 Ice. 
 
 Norite. 
 
 Olivine- 
 Norite. 
 
 
 
 
 
 55.45$ 
 
 45.38# 
 
 55.40:* 
 
 45.300J< 
 
 30.00# 
 
 Ultra-basic 
 Rocks. 
 
 Basic 
 Segrega- 
 tions 
 in normal 
 Magmas. 
 
 Meteorites. 
 Water. 
 
326 PROSPECTING AND VALUING MINES. 
 
 THE PRINCIPAL 
 
 Grand 
 Divisions. 
 
 Origin. 
 
 Structure. 
 
 Material. 
 
 Incoherent 
 State. 
 
 
 
 
 
 Sand. 
 
 
 
 
 
 Gravel. 
 
 
 
 
 
 Shingle. I 
 Rubble, f 
 
 
 
 
 Arenaceous 
 or sandy. 
 
 Volcanic frag- 
 ments. 
 
 
 
 
 
 Volcanic ash. 
 
 Stratified. 
 
 Aqueous 
 and .^Eolian 
 (the latter 
 only slightly 
 stratified, 
 of fine 
 mated Is 
 usually not 
 compacted). 
 
 More or 
 less earthy. 
 
 
 
 Argillaceous 
 or clayey. 
 
 Mud. 
 Clay. 
 
 Calcareous or 
 limey. 
 
 Ooze. 
 Chalk. 
 Chemical pre- 
 cipitate. 
 
 Metamorphic 
 or 
 Transition. 
 
 Aq'.eous, 
 with subse- 
 quent heat, 
 pressure and 
 chemical 
 agencies. 
 
 Roughly 
 stratified; in 
 part crystal- 
 line; usually 
 fissile. 
 
 
 
USEFUL TABLES. 
 
 ROCKS (LE CONTE). 
 
 Compacted State. 
 
 Essential Components. 
 
 Remarks. 
 
 Sandstoi.e. 
 
 Silica, often with iron oxide. 
 
 
 Grit. 
 
 Small pebbles (mostly quartz) ce- 
 mented with silica and iron oxide. 
 
 
 Conglomerate. 
 
 Large pebbles and bowlders 
 similarly cemented. 
 
 
 Breccia. 
 
 Angular fragments (usually volcanic) 
 of various rocks, cemented with 
 silica and iron oxide. 
 
 
 Tufa. 
 
 Fine volcanic dust compacted under 
 water. 
 
 
 Shale, 
 
 Indurated particles of clay, usually 
 with some quartz grains and 
 iron oxide. 
 
 Limestone. 
 
 Calcite, amorphous or partly crys- 
 talline. 
 
 Magnesian lime- i y 
 stone, dolomite, f 
 
 Dolomite and calcite. 
 
 
 Magnesite. 
 
 Magnesite. 
 
 
 Gneiss. 
 
 Mica, quartz, feldspar. 
 
 
 Mica schist. 
 
 Mica, quartz, feldspar. 
 
 
 Chlorite schist. 
 
 Chlorite, quartz, feldspar. 
 
 
 Talcose schist. 
 
 Talc, quartz, feldspar. 
 
 
 Hornblende schist. 
 
 Hornblende, quartz, feldspar. 
 
 
 Garnet schist. 
 
 Garnet, quartz, feldspar. 
 
 
 Slate. 
 
 Hardened shale, cleavage across 
 stratification planes. 
 
 
 Quartzite. 
 
 Altered sandstone. 
 
 
 Marble. 
 
 Altered limestone, calcite. 
 
 
 Serpentine. 
 
 Altered magnesian minerals. 
 
 
328 PROSPECTING AND VALUING MINES. 
 
 THE PRINCIPAL 
 
 Grand 
 Divisions. 
 
 Origin. 
 
 Structure. 
 
 Material. 
 
 Occurrence. 
 
 
 
 
 
 Occurring 
 massive. 
 
 Unstratifled. 
 
 Igneous. 
 
 Crystalline. 
 
 Plutonic or 
 massive. 
 
 
 Occurring in 
 intrusions. 
 
 Volcanic or 
 true eruptives. 
 
 Occurring in 
 overflows. 
 
 Besides the essential components there are many minor u accidental " 
 rphic such as magnetite, pyrite, olivine, etc., but these usually occur in 
 
USEFUL TABLES. 
 ROCKS (LE CONTE). (Continued.) 
 
 329 
 
 Compacted State. 
 
 Essential Components. 
 
 Remarks. 
 
 ACIDIC 
 
 
 
 Pegmatite (graphic 
 
 Large plates of mica imbedded in 
 
 
 granite). 
 
 feldspar. 
 
 
 Granite. 
 
 Quartz, orthoclase feldspar, mica. 
 
 
 Eurite or granulite. 
 Syenite. 
 Quartz syenite. 
 
 A fine-grained granite. 
 Orthoclase feldspar, hornblende. 
 Quartz, orthoclase feldspar, horn- 
 
 Entirely crystalline 
 (holocrystalline) ; 
 
 
 blende. 
 
 usually coarse 
 
 Porphyritic granite 
 
 Large crystals of feldspar in a 
 finer groundmass. 
 
 grained 
 (microcrystalline). 
 
 BASIC-r 
 
 
 
 Diorite. 
 
 Plagioclase feldspar, hornblende. 
 
 
 Quartz diorite. 
 
 Plagioclase feldspar, hornblende, 
 
 
 
 quartz. 
 
 
 Gabbro. 
 
 Plagioclase feldspar, augite, < livine 
 
 
 
 (granitoid variety of diabase). 
 
 
 ACIDIC 
 
 Quartz porphyry. 
 
 Microcrystalline groundmass, with 
 
 
 Felsite. 
 
 larger crysta's of 
 orthoclase and quartz. 
 Microcrystals of orthoclase and 
 
 Microcrystalline 
 groundmass, with 
 or without 
 
 BASIC 
 
 Diorite. 
 
 quartz. 
 Piagioclase and hornblende (micro- 
 
 larger crystals 
 imueaaeci. 
 
 
 crystalline). 
 
 
 Diabase. 
 
 Augite and hornblende (microcrys- 
 
 
 
 talline). 
 
 
 ACIDIC 
 
 
 Glassy ground- 
 
 Rhyalite. 
 
 Vitreous groundmass. with crystals 
 
 mass, with fine to 
 
 
 of quartz an orthoclase 
 
 coarse crystals im- 
 
 
 (sanidin). 
 
 bedded, or wholly 
 
 Trachyte. 
 
 Vitreous groundmass, with crystals 
 
 vitreous. Usually 
 
 
 of orthoclase (sanidin). 
 
 fine-grained (micro- 
 
 Phonolite. 
 Light colored 
 
 Vitreous groundmass, with crystals 
 of sanidin and nepheline. 
 
 crystalline) or im- 
 oerfectly crystal- 
 
 scoriae. 
 Pumice. 
 
 
 ine (cryptocrystal- 
 ine). The following 
 
 Obsidian. 
 
 
 exist in the stony 
 
 BASIC 
 
 
 condition ; rhyolite, 
 
 Andesite. 
 
 Vitreous groundmass, with crystals 
 
 iparite, trachyte, 
 
 
 of plagioclase, augite or hornblende. 
 
 Dhonolite, basalt, 
 
 
 
 dolerite and ande- 
 
 Basalt. 
 
 Vitreous groundmass, with crystals 
 of plagioclase, augite and olivine. 
 
 site. The following 
 are glassy: Scoriae, 
 
 Black scoriae. 
 Tachylite. 
 
 
 pumice, obsidian, 
 and tachylite. 
 
 or accessory minerals in most rocks, especially in the igneous and meta- 
 small proportions. 
 
330 PROSPECTING AND VALUING MINES. 
 
 CLEAVAGE (CROSBY) 
 Kinds : 
 
 In the isometric (I.) system I Cubic, octahedral dodeca- 
 
 tetragonal (II.) system f hedral, etc. 
 
 hexagonal and rhombrohedral (III.) system! 
 
 orthorhombic (IV.) system. ) \ prismatic, basal and 
 
 monoclinic (V.) system ..... > pinacoidal . . . . / pyramidaL 
 
 triclinic (VI.) system . . . . ... ) J 
 
 Degrees : 
 
 Perfect or eminent (like mica). 
 
 Distinct. 
 
 Indistinct or imperfect 
 
 In traces. 
 
 Difficult. 
 
 MINERALS DISTINGUISHED ACCORDING TO TOUCH OR 
 FEEL (CROSBY). 
 
 Meager (like chalk, clay, etc). Smooth. 
 Harsh. Unctuous. 
 
 Rough. Greasy. 
 
 MINERALS DISTINGUISHED ACCORDING TO TASTE (CROSBY), 
 
 Astringent. Saline. 
 
 Cooling. Alkaline. 
 
 Sour. Adhesive. 
 Bitter. 
 
 MINERALS DISTINGUISHED ACCORDING TO ODOR (CROSBY). 
 
 Sulphurous. Argillaceous (like clay) 
 
 Arsenical (like garlic). Fetid (like some limestones). 
 
 Horseradish (selenium). 
 
 SCALE OF HARDNESS (MOHS). 
 
 1. Talc (foliated), very soft. 
 
 2. Gypsum (compact alabaster), can be scratched by the finger nail. 
 
 3. Calcite, can be crushed between the teeth. 
 
 4. Fluorite, easily scratched by knife steel. 
 
 5. Apatite, about the hardness of knife steel. 
 
 6. Feldspar (orthoclase), easily scratched by quartz. 
 
 7. Quartz (crystalline), scratches ordinary glass. 
 
 8. Topaz, easily scratches quartz, 
 
 9. Corundum, scratched only by diamond. 
 10. Diamond, the hardest mineral known. 
 
 Dr. F. M. Endlich says : " In testing the hardness of a mineral by this 
 scale, care should be taken that the pure mineral, not a mixture, is obtained. 
 If a mineral scratches calcit , but is scratched by fluorite, to about the same 
 degree, its hardness lies nearly midway between 3 and 4, and is expressed by 
 3.5. If it barely scratches calcite, but is decidedly scratched by fluorite, the 
 hardness is 33.5; if nearer to fluorite in hardness, but still scratched by 
 it, the hardness is 8.5-4." 
 
USEFUL TABLES. 
 
 VALUES OF METAI^, ORES, MINERALS, ETC. 
 
 331 
 
 [Quotations are those ruling in the United States January 1, 1899. The 
 selling point, when not otherwise stated, is assumed to be New York City.] 
 
 Substance. 
 
 Unit. 
 
 Price. 
 
 Remarks. 
 
 NON-METALLIC. 
 Abrasives: 
 Corundum . . . <, 
 
 Lb. 
 
 Long ton. 
 Long ton. 
 Short ton. 
 Short ton. 
 Lb. 
 Short ton. 
 Lb. 
 Lb. 
 Short ton. 
 100 Ib. 
 100 Ib. 
 Short ton. 
 
 Short ton. 
 
 Short ton. 
 Short ton. 
 
 Long ton. 
 Lb. 
 Short ton. 
 Lb. 
 Lb. 
 
 Bbl. 
 Bbl. 
 Bbl. 
 Short ton, 
 Long ton. 
 
 Short ton. 
 
 Short ton. 
 Long ton. 
 Short ton. 
 Short ton. 
 Short ton. 
 Short ton. 
 Short ton. 
 Lb. 
 100 Ibs. 
 Lb. 
 Lb. 
 Short ton. 
 Short ton. 
 Short ton. 
 IOC Ib. 
 
 4.5-lOc. 
 
 $20. 00-40. 00 
 18.50-32.00 
 38.00-57.00 
 10.50 
 4-40c. 
 $3.00 
 6-18c. 
 17-30c. 
 $12.00 
 1.65 
 1.25-1.75 
 19.50 
 f 40.00 
 ! 18.00 
 j 30.00 
 I 40.00-60.00 
 12.12 
 j 7.75 
 1 10.00 
 3.00-4.50 
 3^-5c. 
 
 $&E 
 
 6% 7^C. 
 
 Best ground 
 Crude Naxos. 
 
 Lump. 
 Lump. 
 Lump. 
 
 Lump. 
 
 Best Cuban. 
 Lower grade. 
 Trinidad. 
 Utah gilsonite. 
 
 Crude. 
 Best. 
 
 Crystal and Powder 
 
 Barrels of 300 Ibs. 
 Barrels of 400 Ibs. 
 Barrels of 350 Ibs. 
 Commercial lump. 
 
 J Domestic f. o. b at 
 1 works. 
 Best 
 Scranton, Pa. 
 Pittsburg. 
 
 Denver. 
 Pittsburg. 
 Denver. 
 
 Best grade. 
 From Greenland. 
 Ground. 
 Lump. 
 Crushed. 
 Lump. 
 
 Diatomaceous or in- 
 fusorial earth ..... 
 
 Emery 
 
 
 
 
 
 Rottenstono 
 
 
 Tripoli 
 
 
 Aluminum sulphate.. . . 
 Asbestos 
 
 
 Asphaltic limestone. . . . 
 Barytes 
 
 Bauxite 
 
 
 Bituminous sandstone . 
 Borax 
 
 Bromine 
 
 45c. 
 
 65c.75 
 $1.75@,2.50 
 1.65 
 2.00-2.10 
 
 $20.25 
 
 7.50-9.50 
 
 4.00-5.00 
 2.00 
 40-70c. 
 $2.95 
 1.25 
 1.84 
 1.25 
 $1.76-1.85 
 57^c.65c 
 3%c. 4c 
 8^c. 
 $7.00-7.75. 
 2.50-4.00 
 6.00 
 75c.85c 
 
 Cement, natural hy- 
 draulic .... 
 
 Cement, Portland 
 
 Cement slag . . . 
 
 Chalk 
 
 Chrome ore 
 
 day china 
 
 Clay fire 
 
 Coal, anthracite, stove 
 Coal bituminous 
 
 Coal cannel 
 
 Coal lignite 
 
 Coke, Connellsville .... 
 Coke, Trinidad 
 Cobalt, oxide 
 
 Copperas 
 
 Copper sulphate 
 Cryolite . .... 
 
 Feldspar 
 
 Flint silica 
 
 Fluorspar 
 
 Fuller's earth 
 
 
332 PROSPECTING AND VALUING MINES. 
 
 VALUES OF METALS, ORES, MINERALS, 'ETC.- Continued. 
 
 Substance. 
 
 Unit. 
 
 Price. 
 
 Remarks. 
 
 Grahamite 
 
 Short ton. 
 Lb. 
 Long ton. 
 100 Ib. 
 Long ton. 
 
 Long ton. 
 
 Long ton. 
 
 Bbl. 
 
 Short ton. 
 Short ton. 
 Long ton. 
 Short ton. 
 Lb. 
 
 $33.00 
 lM-4^c. 
 $4.00 
 2.55 
 3.25-3.65 
 
 2.10-3.25 j 
 
 J 3.25-3.65 
 i 2.55-3.25 
 75c.-$1.00 
 $91.50 
 7.00-8.00 
 2.05 
 8.00 
 4-6c. 
 1 
 
 Ceylon, crude. 
 Rock. 
 Crude. 
 Cleveland, bessemer. 
 Cleveland, non-bes- 
 semer. 
 Cleveland bessemer. 
 " Non-bessemer. 
 Barrels of 250 Ibs. 
 
 Crude lump. 
 
 501 
 
 According to size 
 and quality. 
 Slag. H 
 92#. 
 Imported. 
 American. 
 American. 
 American lead. 
 Chinese quicksilver. 
 English quicksilver. 
 American, dry. 
 American, extra dry. 
 Bbl. of 42 gal., crude. 
 
 American lump ore, 
 Barrels of 280 Ibs. 
 Crude. 
 
 " Square " = 100 sq. 
 ft. as laid on roof. 
 
 Lump, Sicilian. 
 Southern. 
 New York. 
 
 98& 
 
 9o#; 
 
 Sheets. 
 Nickel alloy. 
 Cookson's. 
 Other. 
 Lake. 
 Pittsburg. 
 
 At furnace. 
 
 Graphite (plumbago).. 
 Gypsum . . . 
 
 
 iron ore, hematite 
 Iron ore limonite. . 
 
 Iron ore, magnetite. . . . 
 
 Litharge 
 
 
 Manganese ore . . 
 
 Marble flour , . . . 
 
 Mica ground .... 
 
 
 
 100 Ib. 
 Short ton. 
 Lb. 
 Short ton. 
 Lb. 
 
 Lb. 
 
 Lb. 
 Lb. 
 Bbl. 
 P. unit. 
 Gal. 
 Long ton. 
 Bbl. 
 Lb. 
 Short ton. 
 
 Square. 
 
 Short ton. 
 100 Ib. 
 Lb. 
 Long ton. 
 Short ton. 
 Short ton. 
 Lb. 
 
 Lb. 
 
 Lb. 
 
 Lb. 
 Long ton. 
 Troy oz. 
 Long ton. 
 
 $1.00-4.00 
 140.00 
 6-8c. 
 $8.00-15.00 
 5M-6c. 
 ( 14-1 6c. 
 4 90c. 
 ( 90c. 
 4V4-6C. 
 
 ^- 
 
 7-10c. 
 Be. 
 
 $3.25-5.00 
 3.50-6.00 
 3-3%c. 
 
 $4.00-6.00 
 
 2. 25-10. 50 -j 
 
 11.00 
 1.50-1.60 
 13-1 4c. 
 
 $19.00-21.50 
 10 00 15 50 
 
 Monazite 
 
 
 Paints ocher 
 
 Paints red led 
 
 Paints vermilion 
 
 Paints white lead .... 
 
 Paints zinc white .... 
 
 
 Phosphate rock 
 
 Pitch coal tar 
 
 Pyrites 
 
 Salt ground 
 
 Saltpeter 
 
 Slate ground 
 
 
 Soapstone 
 
 Sodium nitrate 
 Strontium carb. prec . 
 Sulphur 
 
 Talc common 
 
 Talc, fibrous 
 
 8.00-9.00 
 2.00-3.00 
 
 ( 30-34c. 
 30-43C. 
 1 38c. 
 [ 33-39c. 
 J 9i4c. 
 1 8-M-8%c. 
 12%c. 
 $50.00 
 20.67 
 11.25 11.50 
 
 Uranium oxide 
 
 METALS. 
 
 
 Copper 
 
 Ferromanganese 
 Sold 
 
 Iron, No 2 foundry. . . . 
 
USEFUL TABLES. 333 
 
 VALUES OF METALS, ORES, MINERALS, ETC. Continued. 
 
 Substance. 
 
 Unit. 
 
 Price. 
 
 Remarks. 
 
 Iridium 
 
 Gram 
 
 $1.19 
 
 Price in Germany 
 
 Lead. ... 
 
 100 Ibs 
 
 3 75 
 
 New York 
 
 Nickel 
 
 Lb 
 
 33 36c 
 
 Accord'sr to Quantity 
 
 Platinum. . 
 
 Troy oz 
 
 $14 50 16 00 
 
 
 Quicksilver 
 
 Flask 
 
 41 00 
 
 New York; flask of 
 
 Silver.... 
 
 Troy oz 
 
 59^3 60c 
 
 76^ Ibs. 
 Com''! valu 
 
 Spiegeleisen 
 
 Long ton 
 
 $23 00 
 
 
 Zinc 
 
 100 Ib 
 
 5 00 
 
 New York 
 
 RARE ELEMENTS. 
 [Prices given are ai 
 makers' works in Ger 
 many, unless other 
 wise noted.] 
 Barium Amalgam 
 Electrol 
 
 Gram. 
 Gram. 
 
 $1.19 
 5.71 
 
 
 Beryllium Powder 
 Crystals '. . . 
 
 Gram. 
 Gram. 
 
 5.95 
 9.04 
 
 
 Nitrate 
 
 Oz 
 
 2 50 
 
 New York 
 
 Boron- 
 Amorphous, pure 
 Crystals, pure 
 Nitrate 
 
 Gram. 
 Gram. 
 Lb 
 
 19c. 
 : $1.43 
 1 50 
 
 New York 
 
 Calcium Elect' ol 
 Cerium Fused 
 
 Lb. 
 Gram 
 
 4.28 
 2 02 
 
 
 Nitrate 
 
 Lb 
 
 28 00 
 
 New York 
 
 Chromium Fused 
 Pure powder 
 
 Kg. 
 Kg. 
 
 5.95 
 1 79 
 
 
 Chem. pure cryst 
 Cobalt (98@99$) 
 
 Gram. 
 
 Ke- 
 
 19c. 
 
 $5 35 5 71 
 
 
 Pure 
 
 if: 
 
 30 94 
 
 
 Didymium Powder. . . 
 
 Nitrate 
 
 Gram. 
 Oz 
 
 3.81 
 4 00 
 
 New York 
 
 Erbium 
 
 Gram 
 
 3 09 
 
 
 Nitrate 
 
 Oz. 
 
 3.00 
 
 New York 
 
 Gallium. 
 
 Grain 
 
 9 52 
 
 
 Germanium Powder. . 
 Fused 
 
 Gram, 
 Gram 
 
 33.32 
 35 70 
 
 
 Glucinum Powder 
 Crystals ... 
 
 Gram. 
 Gram 
 
 5.95 
 9 04 
 
 
 Nitrate , 
 
 Lb. 
 
 2.50 
 
 New York 
 
 Indium . . . 
 
 Gram. 
 
 4 05 
 
 
 Lanthanum Powder... 
 Electrol, in balls 
 
 Gram. 
 Gram. 
 Oz 
 
 4.28 
 9.04 
 3.50 
 
 New York 
 
 Lithium 
 
 Gram 
 
 2 38 
 
 
 Nitrate 
 Molybdenum Po *vder 
 Fused, electrol 
 Niobium 
 
 Oz, 
 
 Kg. 
 100 grams. 
 Gram 
 
 60c. 
 $2.62 
 15.47 
 3 81 
 
 New York. 
 
 Osmium 
 
 Gram 
 
 95c 
 
 
 Palladium Sponge 
 Sheet and wire 
 
 Gram. 
 Gram. . 
 
 95c. 
 
 $1.70 
 
 
334 PROSPECTING AND VALUING MINES. 
 
 VALUES OF METALS, ORES, MINERALS, ETC. Continued. 
 
 Substance. 
 
 Unit. 
 
 Price. 
 
 Remarks. 
 
 Rhodium 
 
 Gram 
 
 $2 87 
 
 
 Rubidium Pure 
 Ruthenium Pure 
 Selenium Com! pwd'r 
 Sublimed powder. . . . 
 Sticks 
 
 Gram. 
 Gram. 
 Kg. 
 Kg. 
 Kg 
 
 4.76 
 1.55 
 26.18 
 35.70 
 
 28 56 
 
 
 Silicium Amorphous.. 
 Crystals pure 
 
 100 grams. 
 100 grams 
 
 2.87 
 7.14 
 
 
 Strontium Electrol.. . . 
 Tantalum Pure 
 
 Gram. 
 Gram 
 
 6.19 
 3 57 
 
 
 Tellurium C. p. sticks 
 Powder 
 
 100 grams. 
 100 grams. 
 
 11.90 
 9.52 
 
 
 Thallium 
 
 
 23 80 
 
 
 Thorium- 
 Nitrate, 45@-50$ 
 
 Gram. 
 Lb. 
 
 7.85 
 7.50-8.00 
 
 New York, 
 
 Titanium 
 
 Gram. 
 
 71c. 
 
 
 Uranium 
 
 Gram. 
 
 48c. 
 
 
 Nitrate 
 
 Oz 
 
 25c. 
 
 New York, 
 
 Vanadium Fused ..... 
 Wolfram Fused 
 
 Gram. 
 100 grams 
 
 $1.19 
 23.80 
 
 
 Powder, 95@98 
 Chem pure . . 
 
 If: 
 
 2.38 
 7.14 
 
 
 Ore 
 
 IS 
 
 47.60 
 
 Lump. 
 
 Yttrium . 
 
 Gram 
 
 3.33 
 
 
 Nitrate 
 
 Oz. 
 
 4.00 
 
 New York. 
 
 Zirconium Com 1 ! . . 
 
 Ks 
 
 119 00 
 
 
 Pure 
 
 Gram. 
 
 71c. 
 
 
 Nitrate 
 
 Oz 
 
 $1.00 
 
 New York. 
 
 
 
 
 
USEFUL TABLES. 
 
 335 
 
 H 
 
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 ^ 
 
 H 
 
 
 
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 I 
 
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336 PROSPECTING AND VALUING MINES. 
 
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USEFUL TABLES. 337 
 
 The only material standard of customary length authorized by the U. S. 
 Government is the Troughton scale, whose length at 59. 02 Fahr. conforms to 
 the British standard. The yard in use in the United States is therefore equal 
 to the British yard. 
 
 The only authorized material standard of customary weight is the Troy 
 pound of the Mint. It is of brass of unknown density, and therefore not 
 suitable for a standard of mass. It was derived from the British standard 
 Troy pound of 1758 by direct comparison. The British avoirdupois pound 
 was also derived from the latter, and contains 7000 grains Troy. 
 
 The grain Troy is therefore the same as the grain avoirdupois, and the 
 pound avoirdupois in use in the United States is equal to the British pound 
 avoirdupois. 
 
 The British gallon = 4.54846 liters. 
 
 The British bushel = 36.3477 liters. 
 
 By the concurrent action of the principal Governments of the world an 
 International Bureau of Weights and Measures has been established near 
 Paris. Under the direction of the International Committee, two ingots were 
 cast of pure platinum-iridium in i lie proportion of 9 parts of the former to 1 
 of the latter metal. From one of these a certain number of kilograms were 
 prepared, from the other a definite number of meter bars. These standards 
 of weight and length were mtercompared, without preference, and certain 
 ones were selected as International prototype standards. The others were 
 distributed by lot to the different Governments and are called Natio al pro- 
 totype standards. 
 
 The metric system was legalized in the United States in 1866. 
 
 The International Standard Meter is derived from Metre des Archives, and 
 its length is defined by the distance between two lines at Centigrade, on a 
 platinum-iridium bar deposited at the International Bureau of Weights and 
 Measures. 
 
 The International Standard Kilogram is a mass of platinum iridium depos- 
 ited at the same place, and its weight in vacuo is the same as that of the 
 Kilogramme des Archives. 
 
 The liter is equal to a cubic decimeter of water, and it is measured by the 
 quantity of distilled water which, at its maximum density, will counterpoise 
 the standard kilogram in a vacuum, the volume of such a quantity of water 
 being, as nearly as has been ascertained, equal to a cubic decimeter. 
 Long ton: 2240 Ib. avoirdupois =1016 kilogram. 
 Short ton: 2000 " " =907.2 
 
 Pound avoirdupois 453.6 grams. 
 
 Flask of mercury =76)^ Ib. avoir. = 34.700 kilogram. 
 Troy ounce = 31. 104 grams. 
 
 Gallon rr 3. 785 liters. 
 
 Barrel of petroleum = 42 gal. = 1.59 hectoliter, 
 
 " " salt = 280 Ib. 127 kilogram. 
 
 41 " lime = 200 " 90.720 
 
 " " natural cement =300 " 136.080 " 
 
 " " Portland cement = 400 " 181.440 " 
 
 Gold coining value per oz. Troy = $20.6718 = $0.6646 per gram. 
 Silver " " " " Troy = $1.2929 =$0.04157" " 
 
GOOD BOOKS OF REFERENCE. 
 
 [Any of the following books can be obtained at list prices, carriage 
 prepaid, from the Scientific Publishing Co., 253 Broadway, New York, 
 
 ASSAYING. 
 
 Assayer's Guide. By O. M. Liebeiv , 1.50 
 
 Assayer's Manual. By Bruno Kerl .... 3.00 
 
 Assaying. By C. H. Aaron, Part I.^Gold arid Silver Ores $1.00 
 
 Parts II. arid III., Gold and Silver Bullion, Lead, Copper, Tin, 
 
 Mercury 1 .75 
 
 Assaying, A Text-Book on. By C. & J. J. Beringer , 3.25 
 
 Assaying, Manual of Practical. By John Mitchell 10.00 
 
 Assaying, Notes on. By P. de P. Ricketts and H. Miller 3.00 
 
 Assaying of Lead, Copper, Silver, Gold and Mercury. By T. Bodeman 1.50 
 
 Assaying With the Blowpipe, Quantitative. By E. L. Fletcher 1.50 
 
 Practical Metallurgy and Assaying. By A. H. Trliorns 1.50 
 
 Manual of Practical Assaying. By II . Van F. Furman 3.00 
 
 Manual of Assaying. By W. L. Brown 2 50 
 
 and B. Kerl ., . . . i.50 
 
 CHEMISTRY. 
 
 Alkali Maker's Pocket Book, By G. Lunge 3.0G 
 
 Alkali Manufacture in Great Britain, in Vol. II. of " The Mineral In- 
 dustry " ...... 5.00 
 
 Alum and Sulpha:e of Alumina. By John Enequist, in Vol. III. of " The 
 
 Mineral Industry " -5.00 
 
 Briefer Course in Chemistry. By Ira Remsen 1.12 
 
 Chemical Analysis. By D. O'Brine 2.00 
 
 Chemical Analysis of Iron. By A. A. Blair 4.00 
 
 Chemical Analysis, Select Methods in. By Wm. Crookes 8.00 
 
 Chemical and Metallurgical Handbook. By J. H. Cremer and G. A. 
 
 Bicknell 2.75 
 
 Chemical Technology. By C. E. Groves and W. Thorpe 7.50 
 
 Chemical Technology. By R. Von Wagner.. . , 7.50 
 
 Chemistry for Engineers and Manufacturers. By B. Blount and G. 
 Bloxam. Vol. L, Chemistry and Engineering, Building and Metal- 
 lurgy 3..50 
 
 Chemistry, Principles of. By D. Mendeleeff 10.00 
 
 Dictionary of Applied Chemistry. By T. E. Thorpe. Vol. I. (A-I)y), 
 
 $15.00; Vol. II. (Eau-Nux), $15.00; Vol. III. (O-Z), $20.00; complete. . . 50.00 
 
 Electro-Chemical Analysis. By E. F. Smith 1.25 
 
 Electro- Chemistry and Electro-Metallurgy. By W. Borchers. In Vol. 
 
 IV. of " The Mineral Industry " 5.00 
 
 Electro-Chemistry. By G. Gore 80 
 
 Electro-Chemistry. By M ,x Le Blanc 1.50 
 
 Electrolysis. By H. Fontaine 3.50 
 
 Engineering Chemistry. By T. B. Stillman ,V. 4.50 
 
 Industrial Chemistry. By J. Payen 10.50 
 
 Inorganic Chemistry for Beginners. By H. E. Roscoe and J. Lunt . .75 
 
 Laboratory Manual and Principles of Chemistry. By G. M. Richardson. 1.10 
 
 Laboratory Manual. By Ira Remsen 40 
 
GOOD BOOKS OF REFERENCE. 339 
 
 Metallurgical Analysis. By N. W. Lord. , . . 1.25 
 
 Potassium Cyanide Manufacture, By Titus Ulke. In Vol. IV. of ''The 
 
 Mineral Industry " , 5.00 
 
 Qualitative Analysis, Notes on. By W. P. Mason 80 
 
 Qualitative Chemical Analysis, A Short Course in. B. C. A. Schaeffer. 1.50 
 
 Qualitative Chemical Analysis. By F. Clowes. 2.50 
 
 Qualitative Chemical Analysis. By C. R. Fresenius , 5.00 
 
 Qualitative Chemical Analysis. By A. A. Noyes , 1.25 
 
 Qualitative Chemical Analysis. By John A. Miller 1.50 
 
 Quantitative Analysis. By H. C. Bolton 1.50 
 
 Quantitative Chemical Analysis. By T. E. Thorpe 1.50 
 
 Quantitative Chemical Analysis by Electrolysis. By A. Classen 3.00 
 
 Quantitative Chemical Analysis. By H. P. Talbot 1.50 
 
 Quantitative Chemical A alysis. By C. R Fresenius... 6.00 
 
 Salts, Tables and Quantitative Analysis. By M. M. Pattison Muir. = . . . .50 
 
 Sulphuric Acid Manufacture. By Geo. Lunge, 3 vols 35.00 
 
 Volumetric Analysis. By H. W. Shimpf 2.50 
 
 Volumetric Analysis. By F. Sutton 4.50 
 
 ELECTRICITY. 
 
 Electric Transmission of Energy. By G. Kapp, 3.50 
 
 Electric Transmission Handbook. By F. B. Badt. 1.00 
 
 Electrical Distribution. By M H. Kilgour, H. Swan and B. H. W. Boggs 4.00 
 
 Electrical Engineering. By W. Slingo and A. Brooker 3.50 
 
 Electrical Engineering as a Profession. By A. I). Southam 1.25 
 
 Electrical Pocket-Book. By G. Munro and A. Jamieson 2.50 
 
 Electrical Power Transmission. By L. Bell 2.50 
 
 Electrical Transmission of Energy. By A. V. Abbott 4.50 
 
 Electricity and Water Power. By M. A. Replogle 1 .00 
 
 Electricity for Engineers. By C. Desmond . . 2.50 
 
 Electricity in Mining. By S. P. Thompson 80 
 
 EXPLOSIVES AND BLASTING. 
 
 Blasting. By O. Guttmann 3.75 
 
 Blasting and Quarrying. By J. Burgoyne , 60 
 
 Blasting in Mines, Quarries, Tunnels, etc. By A. W. and Z. W. Daw. . . . 6.00 
 
 Explosives and Their Powers. By M. Eerthelot 9.75 
 
 Explosives and Explosive Compounds, A Brief Primer of. By M. 
 
 Berthelot 50 
 
 Lectures on Explosives. By W. Walke 4.00 
 
 Modern High Explosives. By M. Eissler 4.00 
 
 Nitro- Explosives. By P. G. Sanford 3.00 
 
 Rock Blasting. By G. G. Andre 3.0C 
 
 GEOLOGY. 
 
 Aspects of the Earth. By N. S. Sha ; er. 2.5C 
 
 Chemical and Geological Essays. By T. S. Hunt 2.50 
 
 Economic Geology. By R. S. Tarr 4.00 
 
 Elementary Geology. By R. S. Tarr 1.40 
 
 Elements of Geology. By J. LeConte 4.00 
 
 Engineering Geology. By W. H. Penning 1 .40 
 
 Field Geology. By W. H. Penning 1.40 
 
 Field Geology, Outlines of. By A. Geikie 1.00 
 
 Genesis of Ore Deposits. By F. Posepny 2.50 
 
 Geological Story Briefly Told. By J. D. Dana 1.15 
 
 Geology. By A. J. J. Brown 1.00 
 
 Geology. By J. Prestwich. Vol. I. Chemical and Physical 6.25 
 
 Vol II. Stratigraphical and Physical 9.00 
 
 Geology, Class Book of. By A. Geikie 1.10 
 
 Geology, Comparative. Translated by P. Lake 4.50 
 
 Geology, Compend of. By J. LeConte 1.20 
 
 Geology, New Text-Book of. By J. D. Dana 2.00 
 
 Geology of Colorado and Western Ore Deposits. By G. Lake 2.50 
 
340 PROSPECTING AND VALUING MINES. 
 
 Geology, Practical Aids in. By G. A. J. Cole 3.00 
 
 Geology, Principles of. By Sir John Lyell 8.00 
 
 Geology, Text-Book of. By A. Geikie 7.50 
 
 Hand-Book of Rocks. By J. F, Kemp 1.50 
 
 Limestones and Marbles. By S. M. Burnham 6.00 
 
 Lithology. Manual of. By E. H. Williams 3.00 
 
 Manual of Geology. By J. D. Dana 5.00 
 
 Open Air Studies in Geology. By G. A. J. Cole 3.00 
 
 Ore De osits, By J. A. Phillips 7.00 
 
 Ore Deposits of the United States. By J. F. Kemp 4.00 
 
 Ore Deposits, Formation of Eruptive. By I. H. L. Vogt. In Vol. IV. 
 
 of "The Mineral Industry 11 5.00 
 
 Origin of Ores, Views Held To-day. By J. F. Kemp. In Vol. IV. of 
 
 " The Mineral Industry " 5.00 
 
 Railway Guide, An American Geological. By J. Macfarlane 2.50 
 
 Rocks and Soils. By H. E. Stockbridge 2.50 
 
 METALLURGY -GENERAL. 
 
 Aluminum. By J. W. Richards 6.00 
 
 Alloys. Translated and edited by Wm. Brannt 4.50 
 
 Alloys and Their Constituents. By R. H. Thurston 2.50 
 
 Argentiferous Lead Ores, Treatment of. By H. O. Hofman. Articles 
 on this subject are contained in Vols. L, II., III., IV. and V. of " The 
 
 Mineral Industry " each 5.00 
 
 Copper Smelting, Modern. By Edward D. Peters, Jr 5.00 
 
 Copper Sulphate Manufacture at Freiberg. By A. Doerr. In Vol. V. 
 
 of " The Mineral Industry " 5.00 
 
 Electro-Chemistry and Electro-Metallurgy in 1896. By W. Borchers. 
 
 In Vol. V. of " The Mineral Industry." 5.00 
 
 Electro-Chemistry and Electro-Metallurgy, Progress in 1895. By W. 
 
 Borchers. In Vol. IV. of " The Mineral Industry " 5.00 
 
 Electro-Metallurgy. By A. Watt 1.00 
 
 Electro-Metallurgy. By G. Gore 2.00 
 
 Electro-Metallurgy. By W. G. McMillan 3.50 
 
 Lead and Copper Smelting and Copper Converting. By H W. Hixon. . 3.00 
 Lead, Metallurgy of, and the Desilverization of Base Bullion. By H. O. 
 
 Hofman 6.00 
 
 Lead Burning. By J, E. Rothwell. In Vol. IV. of " The Mineral In- 
 dustry " 5.00 
 
 Matte Smelting. By H. Lang 2.00 
 
 Metals, Their Properties and Treatment. By C. L. Bloxam and A. K. 
 
 Huntington 2.00 
 
 Metalliferous Minerals and Mining. By D. C. Davies 5.00 
 
 Metallurgy of Tin. By H. Louis. In Vol. V. of " The Mineral Industry. 1 ' 5.00 
 
 Metallurgy, Introduction to the Study of. By W. C. Roberts- Austen. . . 5.00 
 
 Metallurgy, Elementary. By A. H. Hiorns 1.00 
 
 Metallurgy, Elements of. By J. A. Phillips 9.00 
 
 Metallurgy and Assaying. By A. H. Hiorns 1.50 
 
 Mill Practice in California. By E. E. Preston 1.00 
 
 Progress in Ore Dressing in 1896. By R. H. Richards. In Vol. V. of 
 
 " The Mineral Industry " 5.00 
 
 Rare Elements. By L. M. Dennis. In Vol. V. of "The Mineral In- 
 dustry <)1 5.00 
 
 Recent Improvements in Lead Metallurgy. By H. O. Hofman. In Vol. 
 
 V. of " The Mineral Industry V 5.00 
 
 Regenerator Furnaces. By M. Graham 1.25 
 
 Zinc and Cadmium. By W. R. Ingalls. In Vol. V. of "The Mineral 
 
 Industry. 11 5.00 
 
 Zinc Refining. By Bruno KerL In Vol. V. of " The Mineral Industry. ". 5.00 
 
GOOD BOOKS OF REFERENCE. 341 
 
 METALLURGY -GOLD AND SILVER. 
 Amalgamation of Free-Milling Gold Ores. By L. Janin, Jr. In Vol. 
 
 III. of " The Mineral Industry. 11 5.00 
 
 Barrel Chlorination Process. By J. E. Rothwell. In Vol. V. of "The 
 
 Mineral Industry " 5.00 
 
 Chloridizing Roasting of Calcareous Silver Ore Containing Arsenic in 
 Large Quantities. By O. Hofmann. In Vol. V. of "The Mineral 
 
 Industry. 11 , 5.00 
 
 Cyanide Process. By L. Janin, Jr. In Vol. I. of the Mineral Industry. 11 2.50 
 
 Cyanide Process. By A. Scheidel 1.00 
 
 Cyanide Process. By J. Parks 2.75 
 
 Cyanide Process. By E. B. Wilson 1.50 
 
 .Cyanide Solutions, Precipitation of Gold from. By W. R, Ingalls. In 
 
 Vol. IV. of " The Mineral Industry. 11 , . 5.00 
 
 Getting Gold. By J. C. F. Johnson 1.50 
 
 Gold Amalgamation, Losses in. By W. McDermott and P. W. Duffield. 2.00 
 
 Gold and Silver Ores. By Win. Hamilton Merritt 75 
 
 Gold Chlorination. By J. E. Rothwell. In Vol. I. of " The Mineral In- 
 dustry. 11 2.50 
 
 Gold Extraction at the Witwatesrand. By W. R. Feldtman . , 1.96 
 
 Gold, Metallurgy of. By M. Eissler 5.00 
 
 Gold, Metallurgy of. By T. Kirk Rose 6.50 
 
 Gold Milling. By H. Louis 3.25 
 
 Gold Mines of the Rand. By F. H. Hatch and J. A. Chalmers 5.50 
 
 Gold Ores, Notes on the Treatment of. By F. O'Driscoll 2.00 
 
 Hydro-Metallurgy of the Precious Metals. By Henry Wurtz. In Vol. 
 
 V. of " The Mineral Industry " 5.00 
 
 Leaching of Gold and Silver Ores. By C. H. Aaron 5.00 
 
 Lixiviation of Silver Ores. By C. A. Stetefeldt 5.00 
 
 Ore Roasting. By Kustel 3.00 
 
 Parting and Refining Gold and Silver Ores. By T. Ulke. In Vol. IV. 
 
 of * The Mineral Industry. 11 5.00 
 
 Silver, Metallurgy or. By M. Eissler 4.00 
 
 South Africa, Diamonds and Gold in. By T. Reunert 3.0* 
 
 Stamp Milling of Gold Ores. By T. A. Rickard 2.50 
 
 Yukon Gold Fields, Guide to. By V. Wilson 75 
 
 MINERALOGY. 
 
 Blowpipe Analysis and Determinative Mineralogy. By F. M. Endlich. . 4.00 
 
 .blowpipe Analysis. By J. Landauer 1.00 
 
 Blowpipe in Chemistry, Mineralogy and Geology. By W. A. Ross 2.00 
 
 Determination of Rock- Forming Minerals. By E. Hussack 2.00 
 
 Determinative Mineralogy. By C. G. Wheeler , 1.00 
 
 Gems and Precious Stones of North America. By G. F. Kunz 10.00 
 
 Hand Book of Rocks, for Use Without the Microscope. By J. F. Kemp. 1.50 
 
 Mineralogy. By F. H. Hatch 90 
 
 Mineralogy and Petrography. By J. D. Dana 2.00 
 
 Mineralogy, Crystallography and Blowpipe Analysis. By A. J. Moses 
 
 and C. L. Parsons 2.00 
 
 Mineral' gy, Descriptive, By H. Bauerman 2.00 
 
 Mineralogy, Determinative. By G. J. Brush. 3.50 
 
 Mineralogy, Elements of. By J. Nicol 2.00 
 
 Mineralogy, Handbook of. By J. C. Foye 50 
 
 Mineralogy, New System of. By J. D. Dana 12.50 
 
 Mineralogy, Systematic. By T. S. Hunt. 5.00 
 
 Mineralogy, Text-Book of. By E. S. Dana 3.50 
 
 Minerals, Catalogue of American Localities of. By E. S. Dana 1.00 
 
 Minerals, Catalogue of, and Synonyms. By Thos. Egleston 2.50 
 
 Minerals, Dictionary of Names of. By A. H. Chester. , 3.50 
 
 Minerals, How to Study Them. By E. S.. Dana. 1.50 
 
342 PROSPECTING AND VALUING MINES. 
 
 Petrology, A Text-Book of. By F. H. Hatch 90 
 
 Tables for the Determination of Common Minerals. By W. O. Crosby.. 1.25 
 
 Tables for the Determination of Minerals. By P. Frazer , 1.50 
 
 MINING. 
 
 Accidents, Mining, and their Prevention. By Sir F. A. Abel 4.00 
 
 American Mining Code. By H. N. Copp 50 
 
 Anthrar ite Coal Trade. Evolution of. By R. P. Rothwell. In Vol. IV. 
 
 of " The Mineral Industry.' 1 5.00 
 
 British Columbia Mining Laws 25 
 
 British Columbia, United States and Washington Mining Laws 50 
 
 Coal and Metal Miner's Pocket Book 2.75 
 
 Coal Mining. By H. W. Hughes 6.00 
 
 Coal Mining. By George G. Andre 15.00 
 
 Coal and Coal Mining. By W. W. Smyth 1.60 
 
 Colliery Manager's Calculator. By W. Fairley 1.60 
 
 Colliery Manager's Handbook. By C. Pamely 8.75 
 
 Colliery Working and Management. By H. F. Bulman and R. A. S. 
 
 Redmayne 6.00 
 
 Conversation on Mines. Between Father and Son. By Wm. Hopton. . . . 1.25 
 
 Earthy and Other Minerals and Mining. By D. C. Davies 5.00 
 
 Economic Mining. By C G. W. Lock 5.00 
 
 Hydraulic Mining. By A. J. Bowie 5.00 
 
 Hydraulic Mining. By T. E. Van Wagenan 1.00 
 
 Lead and Zinc Mining Industry of Missouri and Kansas. By J. R. Holi- 
 
 baugh 50 
 
 Metalliferous Mines. Machinery. By E. H. Davies 5.00 
 
 Mine Drainage, Pumps, Etc. By Hans Behr 1.50 
 
 Mine Timbering 1.00 
 
 Mine Ventilation. By E. B. Wilson 1.25 
 
 Mineral Industry, The. Its Statistics, Technology and Trade in the 
 United States and other countries from the earliest times. Vol. I. 
 
 Statistics to the end of 1892 2.50 
 
 Vol. II. Statististics to the end of ,1893. , 5.00 
 
 Vol. III. " 1894 5.00 
 
 Vol. IV. " " 1895 5.00 
 
 Vol. V. " 1896 5.00 
 
 Vol. VI. " " 1897 5.00 
 
 Vol. VII. " " 1898 5.00 
 
 Mineral Lands. By H. N. Copp 4.00 
 
 Minerals, Mines and Mining. By H. S. Osborn 4.50 
 
 Miners 1 Handbook. By John Milne 3.00 
 
 Miner's Pocket Book. By G. W. Lock 5.00 
 
 Miner's Pocket Book. By F. D. Powers. 3.50 
 
 Mines and Mining Men of Colorado 2.50 
 
 Mining. By Arnold Lupton 3.00 
 
 Mining Engineering. By G. C. Greenwell. 6.00 
 
 Mining Laws of Colombia ., 1.50 
 
 Mining Manual for 1896. By W. R. Skinner 5.00 
 
 Mining Rights in the Western States and Territories. By R. S. Morrison. 3.00 
 
 Mixed Metals or Metallic Alloys. By A. H. Hiorns. Illustrated 1 .50 
 
 Modern Coke Ovens and By-Products. By G. Lunge. In Vol. V. of 
 
 " The Mineral Industry. 11 5.00 
 
 Ore and Stone Mining. By C. Le Neve Foster 10.00 
 
 Phosphates of America. By F. Wyatt 4.00 
 
 Practical Notes on Hydraulic Mining. By George H. Evans. 1.00 
 
 Practical Mining. By J. G. Murphy. 1.50 
 
 Prospecting for Gold and Silver. By G. Lake 1.00 
 
 Prospectors, Explorers and Miners, A Practical Guide for. By C. W. 
 
 Moore 4.75 
 
 Prospector's Field Book and Guide. By H. S. Osborn 1.50 
 
GOOD BOOKS OF REFERENCE. 343 
 
 Prospector's Han ] book. By J. W . Anderson 1.50 
 
 Prospector's Manual. By H. N. Copp 50 
 
 Report Book for Mining Engineers. By A. G. Charleton 2.00 
 
 Slate and Slate Quarrying. By D. C. Dayies 2.00 
 
 Story of American Coals. By Win. J. Nicolls 3.50 
 
 Story of a Piece of Coal. By E. A. Martin 40 
 
 Story of the Mine as Illustrated by the Great Comstock Lode. By C. 
 
 H. Shinn 1.50 
 
 Tin Mining. By A. G. Charleton 4.25 
 
 Tunneling. By H. S. Drinker 25.00 
 
 Tunneling. By D. K. Clark . . 12.00 
 
 Ventilation of "Mines. By J. T. Beard , 2.50 
 
 MISCELLANY. 
 
 Civil Engineer's Pocket Book. By J. C, Trau twine. 5.00 
 
 Field Book for Engineers. By Henck 2.50 
 
 Hydraulic Formulae. By T. W. Stone 2.40 
 
 Hydraulic and Water Supply Engineering. By J. T. Fanning. 5.00 
 
 Hydraulics, Practical. By P. M. Randall , 2.00 
 
 Hydraulics, Practical. By T. Box 2.00 
 
 Mechanical Engineer's Pocket Book. By Wm. Kent 5.00 
 
 Petroleum. By W. T. Brannt .. 7.50 
 
 Petroleum. By Beuj. Crew 7.50 
 
 Petroleum Distillation and Modes of Testing Hydrocarbons. By A. N. 
 
 Leet 2.00 
 
 SURVEYING. 
 
 Colliery Surveying. By T. A. O'Donohue 50 
 
 Logarithm Tables. By Webster Wells , 60 
 
 Logarithmic Tables. By Von Vega : 2.50 
 
 Mathematical Tables. By J. Pryde 1.75 
 
 Mine Surveying. By B. H. Broiigh 2.50 
 
 Plane Surveying. By W. J. Raymond 3.00 
 
 Quantity Surveying for Engineers, etc. By J . Leaning 6..00 
 
 Survey Practice. By L. D. Jackson 5.00 
 
 Surveying. By W. M. Gillespie 2.50 
 
 Surveying. A Practical Treatise on. By H. S. Merritt 5.00 
 
 Surveying and Levelling Instruments. By W. F. Stanley 3.00 
 
 Surveying Instruments for Engineers. By I. O. Baker 3.00 
 
 Surveying, Manual of. By F. Hodgman 2.50 
 
 Surveying, Practical. By G. W. Usill,. . ., 3.00 
 
 Surveying, Theory and Practice of. By J. B. Johnson 4.00 
 
 Surveyors' Formulae, Tables and Memoranda. By J. T. Hur t 2.00 
 
 Surveyor's Guide. By A. Duncan 1.50 
 
 Surveyors, Hand Book for. By M. Merriman and J. P. Brooks 2.00 
 
 Subterraneous Surveying. By T. Fenwick and T. Baker. ..,*.., 1.25 
 
PLATE 1. 
 
 1. Idealized step faults. 
 
 Fig. 2. Actual fault in the Leadville district, 
 Fig. 3. Simple fissure without displacement. 
 Fig. 4. Idealized fault, hanging wall depressed. 
 Fig. 5. Idealized fault, reversed, foot wall de 
 
 pressed. 
 FigSo 6, 7, Actual condition of examples 4 and 5, 
 
 showing bent edges of the strata. 
 Fig 8 Contact vein, due to movement of strata 
 
 344 
 
Plate 1 
 
 Fig.l. 
 
 2. Cross Section of ZeadvzIIe jDistricf 
 
 West East 
 
 /ron ///// 
 
 LeadvJ71e 
 
 Quartz/te MM Wfi/'te L/meHi^B/ae Lime 
 
PLATE 2. 
 
 Fig. 1. Illustrating terms used in describing rocks. 
 A 9 conformable series; B, unconformable 
 with A\ C, D 9 E, unconformable with A 
 and B, but conformable among them- 
 selves. 
 
 Fig. 2. Generalized structure of the Gomstock lode. 
 
 Fig. 3. Difference between shales (a) and schists (b). 
 
 Figs. 4. 5. Effect of pressure on the earth's crust, 
 both upward and downward. 
 
 Fig. 6. Faults and throws in veins. 
 
 Figs. 7, 8, 9. Cross section of the Cumberland coal 
 mine, Skagit County, Wash., showing 
 parallelism of coal and iron ore beds. 
 
 346 
 
PLATE & 
 
 Figs. 1, 2, 3. Illustrations of trough faults. 
 Fig. 4. Different forms of fissures, shown horizon- 
 tally. 
 Fig. 5. Anticlinal axis (A) and synclinal axis (B). 
 
 348 
 
Plated Fig. I. 
 
 Fig.4. 
 
 LO 
 
 CJ) 
 
PLATE 4. 
 
 Fig. 1. Folding of rocks; horizontal plan (after 
 
 Geikie). 
 Figs. 2, 3. Cross section of the same rocks (after 
 
 Geikie). 
 Fig. 4. Value of rock exposures to the prospector; 
 
 showing utility of surface croppings, as 
 
 compared with underground workings. 
 Fig. 5. Trough faults in coal seam (after Jukes). 
 Fig. 6. Extreme folding of strata by lateral pressure 
 
 
 
 350 
 
Plate 4 
 
 Fig.3. 
 
 Fig.4. 
 
PLATE 5. 
 
 Figs. 1, 2, 3, 4. Lavas injected into the bedding 
 
 of rocks (after GeikieV 
 
 Fig. 5. Granite intruded into metamorphic schists. 
 Fig. 6. Basalt intruded into coal seam. 
 
 352 
 
PLATE 6. 
 
 Fig. 1. Compression veins in slates or shales (Key- 
 stone mine, Amador County, CaL). 
 
 Fig. 2.* Vein in granite, with spurs. 
 
 Fig. 3. Vein on contact of porphyry dike; one 
 wall "frozen." 
 
 Fig. 4. Vein on contact of porphyry dike, through 
 limestone. 
 
 Fig. 5. Exaggerated representation of "pocket 
 mines" in granite. 
 
 Fig. 6. Eefilling of a lode. 
 
 Fig. 7. Fissure veins, with associated beds, at 
 Tombstone, Ariz. 
 
 Fig. 8. Mineral deposit following joints in lime- 
 stone. 
 
 354 
 
Fig. I. Plate 
 
 Fig.3. 
 
 Fig .4 
 
 Fig. 5. 
 
 Fig.6. 
 
 Fig. 7. 
 
PLATE 7. 
 
 Fig. 1. Cross section of the Wheal Dolcoath, Corn-. 
 
 wall (after C. Le Neve Foster). 
 Fig, 2. Hematite deposit, Ulverstone, England 
 
 (after C. Le Neve Foster). 
 
 Fig. 3. Zinc (calamine) deposit, Altenberg, Ger- 
 many (after C. Le Neve Foster). 
 Fig. 4. "Wheal Mary Ann, Cornwall (after C. Le 
 
 Neve Foster). 
 Fig. 5. Great Flat lode (England), segregated 
 
 deposit (after C. Le Neve Foster). 
 Fig. 6. Cross section of Mother lode in Mariposa 
 
 County, Cal. 
 
 Fig. 7. Bedded porphyry and quartz veins. 
 Fig. 8. Veins of satin spar in conglomerates, Death 
 
 Valley, Cal. 
 Fig. 9. Veins of quartz in conglomerates, Death 
 
 Valley, Cal. 
 Figs. 10, 11. Bedded veins, cropping around hill. 
 
 356 
 
PLATE 8. 
 
 Longitudinal section of Wbeal Dolcoath tin 
 Cornwall (after C. Le Neve Foster). 
 
 358 
 
PLATE 9. 
 
 Fig. 1. Dip of veins. 
 
 Figs. 2, 4. Locating working shafts on a lode. 
 
 Figs. 3, 5. Illustrating course of an outcrop in a hilly 
 country. 
 
 Fig. 6, Bavine formed on lode, when the ore con- 
 sists of soft material. 
 
 Fig. 7. Eake of ore shoots, and formation of ravines 
 across a lode of hard quartz. 
 
 360 
 
/? 
 
 C > 
 
 I 
 
 D \ 
 
 B /I 
 
 Fig 6. 
 
 Fig 7. 
 
PLATE 10. 
 
 Figs. 1, 2, 3. Formation of the ancient buried 
 
 gold-bearing river deposits in California. 
 Fig. 4. Probable length of tunnel to tap the 
 
 "channel." 
 Fig. 5. Side ravine or so-called "overflow" of 
 
 gold-bearing gravel. 
 Fig. 6. Basalt cone (6), through gravel bed (d) 3 
 
 at Laporte, Cal 
 
 362 
 
Fig.!, 
 
 Plate JO ' 
 
 Fig: 2. 
 
 Fig. 3. 
 
 Fig. 4. 
 
 Fig.5, 
 
 Fig. 6. 
 
PLATE 11. 
 
 Fig. 1. Showing present shape and condition of 
 
 the ancient California river channels; 
 
 horizontal plan. 
 Fig. 2. Cross section of Breece & Wheeler placer 
 
 mine, California. 
 Fig. 3. Petrified tree, coated with iron pyrite, 
 
 Sailor Flat, Cal. 
 
 Fig. 4. Fault in placer beds, Grass Flat, Cal. 
 Fig. 5. Eeverse throw of placer beds, Laporte, 
 
 Cal. 
 Fig. 6. Faults in gravel bed, caused by dikes. 
 
 364 
 
Fig. 2 
 
 Fig.3- 
 
 Fig. 4 
 
 Fig.5 
 
 Fig. 6 
 
 C 
 
PLATE 12. 
 
 Figs. 1, 2. Folding of gravel beds at Tacoma, 
 
 Wash. 
 Fig. 3. Section of river bed, showing effect of 
 
 the bed rock on the retention of gold. 
 Fig. 4. Slate quarry, showing stratification lines, 
 
 B y B, and cleavage lines, L, L. 
 Fig. 5. Contact vein, Garibaldi mine, Cal. 
 Fig. 6. Unconformable gravel beds, divided by a bed 
 
 of sinter. 
 Fig. 7. Changes of currents of water in a gravel 
 
 deposit, with petrified trees, Sailor Flat 
 
 mine, Cal. 
 
 Fig. 8. Folding of slates by pressure of dike (D). 
 Fig. 9. Canon or ravine, following fault, Death 
 Valley, Cal. 
 
 866 
 
Fig.2 
 
 Fig. 3. 
 
 Bed of 
 
 Fig, 6 
 
 Fig, 7 
 
 Fig. 9 
 
PLATE 13. 
 
 Figs. 1, 2, 3, 4, 5, 6, 7. Data for estimating quan- 
 tity of ore in a mine. 
 Fig. 8. Miner's born spoon. 
 Fig. 9. Development of mines. 
 Figs. 10, 11, 12, 13. Strike and dip of outcrop. 
 Fig. 14. Mica crystal, 
 Fig. 15. Hornblende crystal. 
 Fig. 16 Augite crystal. 
 
 368 
 
PLATE 14. 
 
 Figs, 1, 2, 3, 4, 5, 6, 7. Showing method of mak- 
 ing locations, good and bad. 
 
 Fig. 8. Artesian well in basin with continuous rim 
 higher than pipe outlet; c, b, d, clay 
 beds; g and e, gravel beds; a, surface 
 dirt; w, well. 
 
 Fig. 9. Artesian well in basin with rim defective 
 on one side; but which flows because the 
 basin is sealed by the water-tight clay 
 bed c; g, gravel bed; a and b } clay seams; 
 w, well. 
 
 370 
 
Fig.5 
 
PLATE 15. 
 
 Figs. 1, 2. Correct form of blaze on trees as witness 
 
 marks. Fig. 1, front view; fig. 2, side 
 
 view. 
 Figs. 3, 4. Good (3) and bad (4) stone-and-stake 
 
 monuments. 
 
 Fig. 5. Posting location notice in tin can. 
 Figs. 6-12. Making locations (see Chap. X.), 
 Figs. 13, 14. Blind lodes; longitudinal and cross 
 
 sections. 
 
 378 
 
Fig.5. 
 
 Fig. I. Fig 2 Fig 5. 
 
 ff.q.S. Del?. 
 
INDEX. 
 
 Abyssinia, Erosion in 159 
 
 Adamantine 207 
 
 Agricultural rights 172 
 
 Alabaster 48 
 
 Alston Moor mine 101 
 
 Altenberg mines 116 
 
 Amador mines 102 
 
 Amorphous. . . . . . . . 207 
 
 Anglesite 216 
 
 Annabergite 224 
 
 Anthracite 262 
 
 Anticlines 146 
 
 Antimonial silver 210 
 
 Antimonides and arsenides 132 
 
 Antimony and country rocks.... 128 
 
 Antimony ores 226 
 
 Apatite 39 
 
 Aqueous theory 106 
 
 Arastra 28 
 
 Arborescent 207 
 
 Area vein worked 33 
 
 Argentite 210 
 
 Arsenic 226 
 
 Arsenical pyrite 221 
 
 Arsenides and antimonides 132 
 
 Artesian wells 310, 315 
 
 Asbestos 229 
 
 Asbestos in hornblende rocks 164 
 
 Asphaltum 231 
 
 Assaying 24 
 
 Assessment work 171 
 
 Atacamite 215 
 
 Atomic weight 316 
 
 Attle 205 
 
 Augite 39 
 
 Autunite 228 
 
 Azurite 214 
 
 B 
 
 Backs 34 
 
 Bald Mountain 134 
 
 Bars, River 298 
 
 Barytes 229, 231 
 
 Basalt 51, 54, 58 
 
 Basalt, Prospecting in 164 
 
 Batopilas .6, 101, 103 
 
 Bauxite 232 
 
 Becker, G. F., on Steamboat 
 
 Springs 107 
 
 Bedding planes 41 
 
 Bedrock 275, 287 
 
 Beds, Dip of 146 
 
 Beds, Ore ................. 144 
 
 Beds, Outcrops of 147 
 
 Beds, Thickness of 69 
 
 Beds, Workable 71 
 
 Bendigo mines 133 
 
 Bibliography 338 
 
 Bismuth, Native 226 
 
 Bismuth ores 226 
 
 Bituminous coal 263 
 
 Black silver , 211 
 
 Blende 218 
 
 Blende and galena. Separating.... 26 
 
 Blind lodes....... 77 
 
 Bog iron ore 8, 143 
 
 Books of reference 338 
 
 Borate of lime 251 
 
 Borax 142, 251 
 
 Borehole records 315 
 
 Borehole, Sperenberg 141 
 
 Borings for coa^ 10 
 
 Borings in gravel 10 
 
 Borings, Useless 8 
 
 Bornite 213 
 
 Botryoidal 207 
 
 Bottom gravel 275 
 
 Bowlder clay 67 
 
 Breccia 66 
 
 Breece & Wheeler mine 277 
 
 Brick clays 243 
 
 Brilliant 207 
 
 Brittle 207 
 
 Brittle silver 211 
 
 Bromide of silver 116, 211 
 
 Buhrstones 61 
 
 Bulk of ores 18 
 
 Burchardite 213 
 
 C. &C. shaft 109 
 
 Cadmium 227 
 
 Calamine 217 
 
 Calaverite . . 210 
 
 Calico district. . . . , 105 
 
 Cannel coal 265 
 
 Canon Creek 158 
 
 Cap rock 278 
 
 Carbonate of copper 214 
 
 Carbonate of lead 216 
 
 Carbonate of zinc 217 
 
 Carmen island salt. 141 
 
 Carpenter F, B., on Dakota gold 
 
 mines 134 
 
 Cascade range 136 
 
INDEX. 
 
 375 
 
 Caspian sea salt . . . , 141 
 
 Caves 148 
 
 Caving 13 
 
 Celestite , 247 
 
 Cerargyrite 211 
 
 Cerussite 216 
 
 Chalcocite 213, 215 
 
 Chalcopvrite 212 
 
 Chalk..: 45 
 
 Charges for locations 191 
 
 Cheshire salt 141 
 
 Chile saltpeter 255 
 
 Chloride of copper 215 
 
 Chloride of silver 116, 211 
 
 Chlorite 89 
 
 Chlorite schists 65 
 
 Chrome and country rocks 128 
 
 Chrome in schists 102 
 
 Chrome occurrences 132 
 
 Chrome ores. 223 
 
 Chromite 223 
 
 Chry socolla 215 
 
 Chrysolite 39 
 
 Chutes 81, 204 
 
 Cinnabar 11, 212 
 
 Claims (See also Locations). 
 
 Claims, Locating 167 
 
 Clay analyse^ 243 
 
 Clay, Bowlder 67 
 
 Clay, Brick 243 
 
 Clay, Fire 234 
 
 Clay gouge 79 
 
 Clay, Mine 14 
 
 Clays 62 
 
 Cleat 263 
 
 Cleavage 40, 330 
 
 Coal..... 259 
 
 Coal beds, Faulted 9 
 
 Coal, Commercial value 269 
 
 Coal, Composition of 260 
 
 Coal, Impurities in 266 
 
 Coal mines, Creeping 1C 
 
 Coal prospecting 269 
 
 Cobalt bloom 2^5 
 
 Cobalt in ocean 107 
 
 Cobalt-nickel 132 
 
 Cobalt ores 225 
 
 Cobaltite. . , 225 
 
 Coke tests 268 
 
 Colombia, Sulphur in 248 
 
 Compact 207 
 
 Compass 165 
 
 Competition 10 
 
 Compression veins 93, 102 
 
 Conistock lode. . . .13, 20. 78. 92, 95, 101 
 107, 109, 111, 112, 113 
 
 Concentration 30 
 
 Conchoidal 207 
 
 Concretionary 207 
 
 Conditions, Favorable 19 
 
 Conglomerate, Volcanic 66 
 
 Conglomerates 60 
 
 Contact veins 91 
 
 Contacts, Limestone , 94 
 
 Contests, Location 195 
 
 Copper and country rocks 126 
 
 Copper chloride 215 
 
 Copper in beds 144 
 
 Copper mines, Lake 100 
 
 Copper, Native 212 
 
 Copper occurrences 131 
 
 Copper ore, Testing. 27 
 
 Copper ores 212 
 
 Copper oxide , 214 
 
 Copper-silver 100, 13^ 
 
 Copper sulphate 213 
 
 Copper surface ores 160 
 
 Coralline limestone 46 
 
 Cornish mines 103, 104, 110, 112 
 
 Corundum 236 
 
 Country rock and gangue 133 
 
 Country rock samples 155 
 
 Country rocks and vein filling 120 
 
 Country roc us, Effect on fissures. 90 
 
 Cracow salt 141 
 
 Creeping .' 13 
 
 Croppings 72 
 
 Cross-cutting 202 
 
 Cross-cut tunnels 197 
 
 Cryolite 236 
 
 Crystal 246 
 
 Crystallization of minerals 320 
 
 Cubanite 213 
 
 Curtis, J. S., on gold and silver in 
 
 rocks 107 
 
 Cuprite 213 
 
 Dacite 55 
 
 Daintree on gold occurrences 107 
 
 Dana on metals in gneiss and 
 
 granite 107 
 
 Dana on nickel in lava 107 
 
 Daubree on meteoroids 108 
 
 Death Valley 88, 101 
 
 Decomposition of ore at surface. . 160 
 
 Deep gravels 276 
 
 Deposits, Evaporated 143 
 
 Deposits, Form of 112 
 
 Deposits in limestone 103, 115 
 
 Deposits, Mineral sediment 143 
 
 Deposits other than veins 138 
 
 Deposits, Physical character of. . . 69 
 
 Depth, Richness in 159 
 
 Derbyshire mines 135 
 
 Development 4, 197, 203 
 
 Diatomaceous earth 48, 240 
 
 Dikes 72,76, 99 
 
 Dikes, Lodes on 94, 154 
 
 Diorite, Gold in 107 
 
 Dip 70, 73, 146 
 
 Discharge of water 304 
 
 Dolcoath mine 13 
 
 Dolomite 47 
 
 Dredging 299 
 
 Drift mining 291 
 
 Drift tunnels 200 
 
 Drifts , , 804 
 
376 
 
 INDEX. 
 
 Dry bone 
 
 Dry washing. 
 Ductile , 
 
 217 
 
 297 
 
 207 
 
 E 
 
 Electro-chemical action 117 
 
 Elements 316 
 
 Elevator, Hydraulic 297 
 
 Elvanite 53 
 
 Embolite 211 
 
 Emerald nickel 224 
 
 Emery 236 
 
 End lines 183 
 
 Epsom salt 142 
 
 Erosion of veins 159 
 
 Erythrite 225 
 
 Evaporation 139 
 
 F 
 
 Faults 83 
 
 Faults in gravels 282 
 
 Faults, Reverse 85 
 
 Faults, Step 86 
 
 Faults, Strike 90 
 
 Faults, Trough 87 
 
 Feel of minerals 330 
 
 Feldspar 37 
 
 Felsite 53 
 
 Fibrous 207 
 
 Filiform 207 
 
 Filling of veins , 99 
 
 Fire clay 62, 234 
 
 " Fissure veins, True 11 89 
 
 Fissures 83 
 
 Flagstones. : 61 
 
 Flaming coal. 264 
 
 Flint 46 
 
 Float , 162 
 
 Floor 69 
 
 Fluorspar 237 
 
 Folded gravels 283 
 
 Foliated 207 
 
 Foot wall tunnels 199 
 
 Forchhammer on metals in sea 
 
 water 106 
 
 Formations, Succession of 138 
 
 Forms of minerals 321 
 
 Fragmental rocks 66 
 
 Franklinite 218 
 
 Eraser river 298 
 
 Freestone 61 
 
 Frieslebenite 211 
 
 Frozen veins 80 
 
 Fuliginous coal 264 
 
 Furnace Creek 104 
 
 Fusibility of minerals 322 
 
 G 
 
 Galena 215 
 
 Galena and blende, Separating. . . 26 
 
 Galena in limestone 102, 164 
 
 Gangue 80 
 
 Gangue and country rock 133 
 
 Garibaldi mine 7 
 
 Garnets 39 
 
 Gas coal. . ............ 3 ..... o ..... 264 
 
 Gas, Natural 258 
 
 Gash veins 86, 95 
 
 Geikie on salt in Caspian 141 
 
 Genthite........ 224 
 
 Geodes 102 
 
 Geologic series. 67, 322, 323 
 
 Geological Survey, U. S 68 
 
 Georgia mines 136 
 
 Gersdorffite... 224 
 
 Glacial depo its 285 
 
 Glacial products 67 
 
 Glacier mine '. 114 
 
 Gneiss 64 
 
 Gneiss and granite. Ores in 107 
 
 Gob 205 
 
 Gold and country rocks 122 
 
 Gold and silver in rocks 107 
 
 Gold, Crystallized 101 
 
 Gold gravel deposits 271 
 
 Gold gravels, Faults in 282 
 
 Gold gravels, Folds in 283 
 
 Gold in beds 144 
 
 Gold in diorite 107 
 
 Gold in granite , 102 
 
 Gold in sea water 106 
 
 'Gold in serpentine 107 
 
 Gold in South Dakota 134 
 
 Gold, Native 209, 259 
 
 Gold occurrences 131 
 
 Gold ore. Assaying 24, 25 
 
 Gold ore, Free 12 
 
 Gold ore, Horning 25, 26 
 
 Gold ore, Testing 25 
 
 Gold pan 288 
 
 Gold, Saving fine 299 
 
 Gold, Tests for 296 
 
 Gold tellurides 209 
 
 Gold veins, Erosion of 159 
 
 Gouge 79 
 
 Grade of gravel deposits 275 
 
 Grade of ore 21 
 
 Grand Canon 159 
 
 Granite 37, 52 
 
 Granite, gold in K 2 
 
 Granite, Veins in 97 
 
 Granular 207 
 
 Graphite 238 
 
 Gravel deposits 271 
 
 Gravel deposits, Origin of 272 
 
 Gravel mines, Clay in 14 
 
 Gravel mines, Creeping in 13 
 
 Gravel mining 286 
 
 Gravel, Faults in 282 
 
 Gravel, Folds In 283 
 
 Gravel, Testing 296 
 
 Gray copper 213 
 
 Great Flat lode 112 
 
 Gypsum 14, 48, 143, 239 
 
 Gypsum in solution 141 
 
 H 
 
 Hammers, Geological 166 
 
 Hanging wall tunnels. 199 
 
INDEX. 
 
 37? 
 
 Head Center mine 100 
 
 Head of water 304 
 
 Heading 204 
 
 Heat, Underground 109 
 
 Hematite 219 
 
 Hillside deposits 283 
 
 Horn silver ,100, 105, 211 
 
 Horn spoon 25, 165 
 
 Hornblende 39 
 
 Hornblende rocks, Asbestos in 164 
 
 Horses 79, 91 
 
 Hydraulic elevator. 297 
 
 Hydraulic mining 289 
 
 Igneous theory. 
 Illinois mines. . . 
 
 I 
 
 115 
 
 Ilmenite 221 
 
 Inch, Miner's 302, 309 
 
 Incline 204 
 
 Infusorial earth 48, 240 
 
 Iridescent 207 
 
 Iridosmine 212 
 
 Iron carbonate 220 
 
 Iron-manganese 132 
 
 Iron ore beds 143 
 
 Iron ore, Bog 8, 143 
 
 Iron ores 219 
 
 Iron sulphide 220 
 
 Isabel mine 105 
 
 Joints, Strike 41 
 
 Jukes on trough faults 87 
 
 Kaolin 62 
 
 Karaboghaz salt 141 
 
 Keystone mine 93, 112 
 
 Killas 103 
 
 Lake Superior mines 144 
 
 Lakes, Saline 59 
 
 Lamination 41 
 
 Land prices 195 
 
 Lands, Agricultural 172 
 
 Lands, Timber 172 
 
 Lapilli 66 
 
 Laterals 281 
 
 Lava 50, 51 
 
 Lava cup 278 
 
 Lava, Nickel in 107 
 
 Lead 72 
 
 Lead and country rocks 125 
 
 Lead and silver 132 
 
 Lead carbonate 216 
 
 Lead in Derbyshire 135 
 
 Lead in limestone 115, 164 
 
 Lead, Native 215 
 
 Lead occurrences 131 
 
 Lead ore .9, 101 
 
 Lead ore in beds 144 
 
 Lead oxide 216 
 
 Lead sulphate. 216 
 
 Lead-zinc 182 
 
 Leadville .9, 92, 148 
 
 Ledge 72 
 
 Leeds mine 105, 144 
 
 Levels 204 
 
 Light and minerals 320 
 
 Lime sulphate 239 
 
 Limestone .45, 241 
 
 Limestone, Caves in 148 
 
 Limestone contacts , 94 
 
 Limestone, Coralline 46 
 
 Limestone, Deposits in... 103, 115, 164 
 
 Limestone, Prospecting in 164 
 
 Limonite 219 
 
 Litigation 14 
 
 Liversidge on gold in sea water. . 107 
 
 Locating regulations 189 
 
 Location charges 191 
 
 Location end lines 183 
 
 Location, Final proof of 194 
 
 Location length 183 
 
 Location notices 175, 176 
 
 Location, Publication of 193 
 
 Location requirements 168 
 
 Locations, Describing 150 
 
 Locations, How made 170, 177 
 
 Locations, Imperfect 168 
 
 Locations, Lode 171, 177, 188 
 
 Locations, Making 167 
 
 Locations, Placer 170 
 
 Locations, Procedure in 191 
 
 Locations, Puzzling 185 
 
 Lode 72 
 
 Lode length 183 
 
 Lode line 179 
 
 Lode locations 171, 177, 188 
 
 Lode locations, Procedure in 188 
 
 Lodes, Blind 77 
 
 Lodes on dikes 94 
 
 Lost vein 6 
 
 M 
 
 Machine washing 295 
 
 Magnesite 47, 242 
 
 Magnet 165 
 
 Magnetite 219 
 
 Malachite 214 
 
 Malleable 207 
 
 Mammillary . . 208 
 
 Mammoth cave 115, 148 
 
 Manganes^ and country lodes.... 129 
 
 Manganese in ocean 107 
 
 Manganese-iron 132 
 
 Manganese occurrences 132 
 
 Manganese ores 221 
 
 Marble .. 47 
 
 Marcasite 220 
 
 Marks, Stake , 173 
 
 Marks, Tree 173 
 
 Masses 81 
 
 Massicot . 216 
 
 Massive 208 
 
 Matrix. 80 
 
 Mary Ann mine 110, 112 
 
378 
 
 INDEX. 
 
 Melaconite 214 
 
 Mercury (See Quicksilver). 
 
 Metacinnabarite 212 
 
 Metallic luster 208 
 
 Metallurgical experiments 3 
 
 Metallurgical plant, Planning 29 
 
 Metals and rocks 130 
 
 Metals associated with each other 132 
 
 Metals, Distribution of 106 
 
 Metals, Sp. gr. of 17. 18 
 
 Metals, Value of .' 331 
 
 Meteoroids 108 
 
 Metamorphic rocks. . 64 
 
 Metamorphism 42 
 
 Metric system. 335 
 
 Mica 38, 242 
 
 Micaceous , 208 
 
 Mill capacity 32, 33 
 
 Mill runs 27 
 
 Millstones 61 
 
 Mine cost and output 16 
 
 Mine, Definition of 34 
 
 Mine failures, Causes of 14 
 
 Mine water 157, 201 
 
 Mine, What constitutes a 16 
 
 Minerals. Characters of 320 
 
 Minerals, Classification of 318 
 
 Minerals Cleavage of 330 
 
 Minerals, Crystallization of 320 
 
 Minerals distinguished according 
 
 to feel 330 
 
 Minerals distinguished according 
 
 to odor 330 
 
 Minerals distinguished according 
 
 to taste 330 
 
 Minerals, External Forms of 321 
 
 Minerals, Fracture of 321 
 
 Minerals, Fusibility of 322 
 
 Minerals, Hardness of 330 
 
 Mineral " in place " 172 
 
 Minerals, Insoluble 229 
 
 Minerals, Qualities Depending on 
 
 Light of 320 
 
 Minerals, Rock-forming 36 
 
 Minerals, Separating 26 
 
 Minerals, Soluble 250 
 
 Minerals, Structure of 321 
 
 Minerals, Useful 229 
 
 Minerals, Value of 331 
 
 Minerals, Worthless 11 
 
 Miner's inch 302, 309 
 
 Mines, Development of 4, 197, 203 
 
 Mines, Unsuccessful , 10 
 
 Mines, Working facilities 157 
 
 Mining conditions 19 
 
 Mining Drift 291 
 
 Mining failures 2, 14 
 
 Mining ground, Patents to 187 
 
 Mining, Hydraulic . . . . . 289 
 
 Mining, Mistakes in 1 
 
 Mining, Placer 286 
 
 Minium 217 
 
 Mispickel 221, 225 
 
 Molybdenum 227 
 
 Mono lake 
 
 Monte Cristo district 78, 113, 
 
 Monuments 173, 174, 
 
 Mother lode 76, 104, 119, 
 
 N 
 
 . , mines 
 
 Nagygite 
 
 Natural gas 
 
 Niccolite 
 
 Nickel and country rocks. . 
 
 Nickel-cobalt 
 
 Nickel in lava. 
 
 Nickel in ocean ..., 
 
 Nickel ocher 
 
 Nickel ore 
 
 Nickel silicate 
 
 Niter 
 
 Niter, Chile 
 
 Niter (See Saltpeter). 
 Notic"s of locations 
 
 Notices, Posting 
 
 Nova Scotia schists 
 
 Obsidian 
 
 Ocotilla 
 
 Odor of Minerals , 
 
 Opals in basalt 
 
 Olivine 
 
 Onion Valley dike 
 
 Oolitic 
 
 Opaque 
 
 Ore change at water level 
 
 Ore, Definition of 
 
 Ore deposits and country rocks. . . 
 
 Ore deposits, Form of , 
 
 Ore, Distribution of 
 
 Ore, Grade of 
 
 Ore in depth 
 
 Ore in limestone 103, 115, 
 
 Ore "in sight 11 
 
 Ore, Origin of 
 
 Ore, Pockety 
 
 Ore sampling 
 
 Ore, Solution of 
 
 Ore, Source of 
 
 Ore supply needed 
 
 Ore deposits, Physical char, of ... 
 
 Ore thickness 
 
 Ore tonnage 
 
 Ores arid rocks 
 
 Ores, Bulk of 
 
 Ores from sea 
 
 Ores, Separating. 
 
 Ores, Sp. gr. of 17, 
 
 Ores, Value of 
 
 Ores, Weight of 
 
 Orpimen t 
 
 Otago mines 
 
 Outcrop 
 
 Outcrop and springs 
 
 Outcrop and vegetation 
 
 Outcrop in location 
 
 Outcrop, Lesson of the 7, 
 
 142 
 114 
 181 
 154 
 
 6 
 210 
 258 . 
 224 
 128 
 , l&J 
 , 107 
 , 107 
 , 224 
 , 224 
 . 224 
 . 254 
 . 255 
 
 , 175 
 , 176 
 . 133 
 
 . 56 
 . 152 
 . 330 
 . 164 
 . 39 
 . 99 
 . 208 
 . 208 
 . 159 
 206 
 122 
 112 
 12 
 21 
 159 
 164 
 21 
 106 
 6 
 
 23 
 109 
 111 
 31 
 69 
 153 
 32 
 130 
 18 
 116 
 26 
 18 
 331 
 19 
 226 
 133 
 72 
 153 
 152 
 179 
 158 
 
INDEX. 
 
 379 
 
 Outcrop of veins 74 
 
 Outcrop, Circular 78 
 
 Outcrop, Rusty 161 
 
 Outcrops of beds 147 
 
 Outfit, Prospecting 165 
 
 "Overflows," Gravel 281 
 
 Oxides of iron 219 
 
 Ozokerite 244 
 
 Pan , 2 
 
 Panning 
 
 Patents 1&7 
 
 Patents, Procedure in 191 
 
 Petroleum 257 
 
 Petzite 210 
 
 Phosphate of uranium 228 
 
 Pick, Prospecting 166 
 
 Pipe clay 278 
 
 Pipes, Water in 304 
 
 Pisolitic 208 
 
 Pits, Prospect 2( 
 
 Placer locations 170 
 
 Placer mining 286 
 
 Plaster of paris 48, 239 
 
 Platinum < 211 
 
 Plumbago 238 
 
 Pockets 6 
 
 Pockets, Fault 85 
 
 Porcelain clay 62 
 
 Porphyry 53, 55, 58 
 
 Posting notices 176 
 
 Potassinm nitrate 254 
 
 Potter's clay 243 
 
 Price and profits 20 
 
 Prices of metals,ores, minerals,etc. 331 
 
 Promoters 4 
 
 Prospecting 150 
 
 Prospecting and springs 15 f <5 
 
 Prospecting and vegetation 152 
 
 Prospecting and water system 163 
 
 Prospecting for coal 269 
 
 Prospecting outfit 165 
 
 Prospecting W T hat to look for.... 164 
 
 Prospecting Where? 164 
 
 Prospect pits 203 
 
 Proustite = 211 
 
 Psilomelane 222 
 
 Publication of location 193 
 
 Pumice 243 
 
 Pyrargyrite 210 
 
 Pyrite 220 
 
 Pyrite, Auriferous 27 
 
 Pyrite, Decay of 114, 161 
 
 Py rolusite 222 
 
 Pyrrhotite 221, 224 
 
 Q 
 
 Quartz 37, 243 
 
 Quartz porphyry 55 
 
 Juarzfte 61 
 
 Quicklime 47 
 
 Quicksilver and county rocks 129 
 
 Quicksilver at Steamboat Springs. 107 
 Quicksilver for testing 165 
 
 Quicksilver, Native 212 
 
 Quicksilver occurrences 132 
 
 R 
 
 Ramsay on Bath salts 139 
 
 Realgar 226 
 
 Reduction works, Plan ing 29 
 
 Reduction works, Unsuitable .... 5 
 
 Regulations for locating 189 
 
 Regulations, Local 171 
 
 Reniform 208 
 
 Reserves 4, 5, 34 
 
 Resinous 208 
 
 Reverse throws 85 
 
 Rhyolite 35 
 
 Ribbon rock 95 
 
 Ribbon structure 110 
 
 Richmond Con. mine 4 
 
 Rio Virgen salt 141 
 
 River bars 298 
 
 River deposits 274 
 
 Roads 29 
 
 Rock and gangue 133 
 
 Rock names 156 
 
 Rock samples 155 
 
 Rocks 36 
 
 Rocks and metals 130 
 
 Rocks, Ohem. precipitated 44 
 
 Rocks, Classification of . . . .43, 324, 326 
 
 Rocks, Composition of 58 
 
 Rocks, Compound 49 
 
 Rocks, Crystalline 50 
 
 Rocks, Effect on fissures 90 
 
 Rocks, Eruptive 133 
 
 Rocks, Fragmental 66 
 
 Rocks, Influence on vein filling. . . 120 
 
 Rocks, Metam orphic 64 
 
 Rocks, Organic 44 
 
 Rocks, Origin of 44 
 
 Rocks, Silicious 131 
 
 Rocks, Simple 45 
 
 Rocks, Stratified 57 
 
 Rocks, Volcanic 66 
 
 Roof 69 
 
 Ruby Basin 134 
 
 Ruby silver 210, 211 
 
 Rutile 227. 
 
 s 
 
 Salt 141, 256 
 
 Salt at Sperenberg 141 
 
 Salt in Arizona 141 
 
 Salt in Caspian 141 
 
 Salt in Cheshire 141 
 
 Salt in Poland 141 
 
 Salt in solution 141 
 
 Saltpeter 142, 254 
 
 Saltpeter. Chile 255 
 
 Saltpeter prospecting 164 
 
 Salts, Soluble, Prospect ng for. . . ie:4 
 
 Samples country rock 155 
 
 Sampling 23 
 
 Sandberger on metals in rocks. . .. 107 
 
 Sandstones , 61 
 
 Satin spar 101, 239 
 
380 
 
 INDEX. 
 
 Savage mine 
 
 Schists 42, 
 
 Sea beach deposits 
 
 Sea-formed ores 
 
 Sea water. Metals in , 
 
 Sediment mineral deposits 
 
 Segregated veins 
 
 Selenite 48, 
 
 Selvage 
 
 Semi-anthracite 
 
 Semi-bituminous 
 
 Serpentine , 
 
 Serpentine, Gold in 
 
 Shafts 3, 200, 
 
 Shafts, Useless 
 
 Shales 
 
 Shoots, Ore 81, 
 
 Siderite 
 
 Sierra Nevada mine 
 
 Silicate of nickel 
 
 Silicate of zinc 
 
 Silver and country rocks 123, 
 
 Silver and gold in rocks 
 
 Silver at Leeds 105, 
 
 Silver, Brittle . . . . 
 
 Silver bromide 116. 
 
 Silver chloride 116. 
 
 Silver-copper 100, 
 
 Silver glance 
 
 Silver in sea water 
 
 Silver in South Dakota 
 
 Silver-lead. 
 
 Silver, Native 101, 
 
 Silver occurrences 
 
 Sinking. 
 
 Sinter 
 
 Slate 42, 43, 
 
 Slate Creek 
 Slickensides 
 
 Smaltite 
 
 Smelting 
 
 Smithsonite 
 
 Soapstone 
 
 Sodium carbonate 
 
 Sodium sulphate 
 
 Solfataric action 
 
 Solutions, Mineral 109, 134, 
 
 South African mines 
 
 South Dakota mines 
 
 Specific gravity 17, 
 
 Sperenberg boring 
 
 Spoon 
 
 Springs and outcrops 
 
 Spurs 78, 
 
 Stakes 
 
 Stalactitic 
 
 Stamp, Duty of 
 
 Stamp mill capacity 
 
 Stannite 
 
 Steamboat Springs 
 
 Step faults 
 
 Stephanite 
 
 Stibnite 
 
 Stockworks 89, 
 
 113 Stone monuments 173 
 
 65 Stonewall Jackson mine 95, 135 
 
 284 Stoping 204 
 
 116 Stratification 40, 60 
 
 106 Streak plate 166 
 
 143 Stream tin 223 
 
 95 Strike 70, 74 
 
 239 Strike faults 90 
 
 . 79 Strike joints 41 
 
 262 Strontia 246 
 
 263 Structure of minerals 321 
 
 49 Stulls 205 
 
 107 Subconchoidal 258 
 
 201 Submetallic 258 
 
 8 Sulphate of copper 215 
 
 63 Sulphate of (sad 216 
 
 204 Sulphate of soda 256 
 
 220 Sulphide of iron 220 
 
 101 Sulphide of mercury 212 
 
 224 Sulphide of tin ' 223 
 
 217 Sulphide of zinc 218 
 
 124 Sulphur 247 
 
 107 Sulphur Banks 248 
 
 144 Sulphurets, Panning 166 
 
 211 Sulphurets, Separating 26, 166 
 
 211 Sump 205 
 
 211 Surface ores 159, 160, 161 
 
 132 Survey, Order for 192 
 
 210 Surveyor, Authority of 169 
 
 106 Surveyor, Duties of 188, 190 
 
 134 Surveyor's fees 188 
 
 . 132 Surveyors, Instructions to .... 189, 196 
 
 210 Sutro 'tunnel Ill 
 
 131 Slitter Creek mines 102 
 
 200 Syenite .......54, 58 
 
 46 Sylvanite 210 
 
 , 63 Synclines 146 
 
 % T 
 
 f>25 Tables: ...... 316 
 
 29 Elements 316 
 
 217 Geologic Series 67, 322, 328 
 
 249 Metals, Ores, Minerals, etc., 
 
 253 Value of 331 
 
 256 Metric System 335 
 
 111 Minerals, Characters of 320 
 
 139 Minerals, Classification of 318 
 
 144 Minerals, Cleavage of 40, 330 
 
 134 Minerals, Crystallization of 320 
 
 18 Minerals distinguished accord- 
 
 141 ing to feel 330 
 
 25 Minerals distinguished accord- 
 
 153 ing to odor 330 
 
 84 Minerals distinguished accord- 
 
 173 ing to taste 330 
 
 258 Minerals, External forms of 321 
 
 32 Minerals, Fracture of 321 
 
 33 Minerals, Fusibility of 322 
 
 223 Minerals, Hardness of 330 
 
 107 Minerals, Qualities depending 
 
 86 on light of 320 
 
 211 Minerals, Structure of 321 
 
 226 Rocks, Classification of.. 43, 324. 326 
 
 103 Talc 249 
 
INDEX. 381 
 
 Talus 77 Veins not uniform 12 
 
 Tape .165 Veins on dikes ..94, 154 
 
 Taste of minerals 330 Veins, Opening 157 
 
 Tellurides 195, 209 Veins, Origin of , . .83, 96 
 
 Tests, U tility of 28 Veins, Pockety , 119 
 
 Tests, Working 27 Veins, Richness in depth 159 
 
 Tetrahedrite 213 Veins, Segregated 95 
 
 Theory-, Aqueous 106 Veins, Thickness of 69, 153 
 
 Theory, Igneous 99 Veins, 4k True fissure " 72, 89 
 
 Thickness of vein and ore 153 Velocity of water discharge 305 
 
 Throw 84, 85 Vesuviau lava 107 
 
 Timber rights 172 Vitreous copper 213 
 
 Time, Geologic 68 Vitreous silver 210 
 
 Tin and country rocks 128 Volcanic products e 66 
 
 Tin occurrences 131 w 
 
 Tin ore 11, 222 
 
 Tiusulphide 223 w a ? : 222 
 
 Titanic iron 221 Was, False 154 
 
 Titanium 227 "WSj vein 79 
 
 Tombstone .':.'.'.':.':::.'.".v.'.'.v.Vii6, 157 s***? m i nes 95 ' 113 ' * 
 
 Tonnage area 17 Water, Bulk of 302 
 
 Toimaircafcuiationof:;:::::.8i; 32 Water discharge 304 
 
 Tonotrranhv 163 Water in mines 1 57, 201 
 
 To?b!rn1?e y :::.v.v.v:.:.v. :;::;::: * water level 159 
 
 Tourmaline 39 Water measurement 306 
 
 Trachyte 53, 58 Water, Mine 108 
 
 TrAnafiiftpnt 2^ Water power 305 
 
 TransparentV/.-.V.-.-.-.-.-.-.-.-.-.-: '. '. '. '. '. '. 858 Water P re f re - : * 
 
 Transpr'taf n of mineral by water 109 Water system and prospecting. . . ua 
 
 r rm t"> ^7 ** ater, u nit or oO,* 
 
 Tmna'" " 253 Water, Weight 302 
 
 Trough faults'. '. '. '. '. '. '. '. .' .' .' .' .' . .' ." '. .' .' .' .' 87 Waters, Solvent power of 139 
 
 -True fissure ve.ns " 89 WMgj^^.^^.;.,...^., 958 
 
 TungsVen\\\\\\\'::.v.v:::::::::::: 22? weight of ores 19 
 
 Tunnel connections 199 Weirs . J06 
 
 Tunnels, Cross-cut 197 West Point, Cal. 102 
 
 Tunnels Drift 200 Whea Dolcoath 110 
 
 Tunnels in foot or hanging wall... 199 Wheal Mary Ann 110, 112 
 
 Tyndall mine '. 78 Wjjjemite |$ 
 
 U Wisconsin mines 115 
 
 Ulexite 251 Wolfram 227 
 
 Ulverstone deposits 116 Wood tin , 223 
 
 Uranium 228 Working facilities 157 
 
 y Works, Planning , 29 
 
 . Works, Unsuitable 5 
 
 Valuation of mines 20 
 
 Values of metals, ores, minerals, Y 
 
 etc 331 Yale 298 
 
 Vanadium .'?? Yankee Hiti.' .'.'.'.'.'.'.'.'.'.'. '.'.'.'.'. '.'.'.'.'.'. 101 
 
 Vegetation a guide in prospecting 153 Yellow Jacket mine 109 
 
 Vein, Area extracted 33 Yucca... 152 
 
 Vein, Distance traceable 151 ........ 
 
 Vein filling 99 *- 
 
 Vein matter 80 Zinc and country rocks 127 
 
 Vein structure 6 Zinc at Altenberg 116 
 
 Veins, Blind 77 Zinc carbonate 217 
 
 Veins, Compression. 93, 102 Zinc occurrences 131 
 
 Veins, Contact 91 Zinc ores 217 
 
 Veins, Definition of 72 Zinc oxide 218 
 
 Veins, Frozen 80 Zinc silicate 217 
 
 Veins in granite ". 97 Zincblende 218 
 
 Veins, Measuring 153 Zincite 218 
 
 Veins, Narrow 6 Zinc-lead , . , , 133 
 
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