widely known. The gold mines may be included in four classes: 1. Placers. 2. Quartz veins between slate walls. 3. Quartz veins between porphyry walls. 4. Cement deposits.

"The placers in the Black Hills are of great extent, and some of them have yielded very large sums. Some of the dry places (that is, beds of clay or gravel, containing a considerable amount of free gold, but at such a distance from water having sufficient head to wash the gold, and

consequently requiring that the dirt should be brought to the water, or the water to the placer at considerable cost), have proved so rich that the dirt has been brought from some of them by wagon loads to the water, and where they were more extensive, it has been found profitable to construct ditches or flumes of several miles in length, to bring a mountain stream to supply the pipes for hydraulic mining.

"These placers are many and seem to be distributed all over the Hills, and being rich and mostly undeveloped, it

is likely that placer mining will be conducted with great profit here for many years to come. A placer claim in the Black Hills extends three hundred feet along the gulch, and from rim to rim.

"The second class of gold mines found in the Black Hills, quartz in slate, or between slate walls, is represented by the great belt around Deadwood, on which the mammoth mines of the hills are situated. The country rock, that is, the rock of which the mountains are formed, is micaceous slate, which has been thrown up at an angle of about fifty degrees. Between the walls of this slate is a vein of brown quartz containing free gold in small quantities, and separated from the country rock on each side by a layer of chloritic slate, often containing more gold than the quartz itself. The vein is of enormous width, from 40 to 150 feet, but is frequently divided by horses' of slate, or large bodies of that substance extending into, or across the vein. The rock in these horses' is sometimes rich enough to work, but generally is quite barren.

"There are two theories of the formation of these veins; and while there seems to be sufficient ore in all the large mines for present purposes, the future of these properties may depend in great degree upon which of these theories proves to be the correct one. The first is that advanced by Professor Jenney, the young geologist who was sent by the Department of the Interior. He holds that these ledges of gold-bearing rock, are true fissure veins, interlaminated fissures' he calls them, that is, fissures opened between the layers of the slate rock, and not across the line of stratification. The auriferous quartz, he says, has been formed by the water solutions which have come up from below. He accounts for the horses' of slate in the vein by likening the cleaving of the rock to the splitting of a piece of oak wood. When a wedge is driven into it, particles of the wood cling from side to side across the opening made by the wedge. So, he thinks, when the rock was opened, bodies of slate extended across from one wall to the other, and remained in that position when the

aqueous solution from below came up, surrounded them, and deposited the gold-bearing quartz.

"He explains the fact that the slate walls and horses' contain gold, by saying that the slate, which had minute spaces between its layers, soaked up the mineral-bearing fluid, which in some cases replaced the particles of slate. As a rule, the impregnation of the slate becomes less as the distance from the wall of the vein increases. Believing the veins to be true fissures, Professor Jenney supposes that they extend into the earth for an indefinite distance and probably grow richer in their lower portions. Professor Jenney believes that after these veins were formed the ocean covered what are now the Black Hills, and that by its action it tore down the surface, scattering fragments of veins all over the country. Evidences of marine action are easily to be found in the vicinity of the mines.

“The other theory held by several geologists of much learning and experience is, that the vein matter was precipitated from an aqueous solution that covered it. Their explanation and argument is this: The foot wall of these veins is slate, a formation which everybody knows is of aqueous origin. The vein of quartz is deposited on this slate parallel with its line of stratification, just as one layer of rock is deposited on the other. Above the vein we also find slate, and above that where it has not been carried away by the actions of the elements, a cement formation also of aqueous origin. These facts point conclusively to a horizontal deposit of the vein matter on a slate bed. The precipitant was probably oxide of iron, and it is, therefore, very natural that these ores containing the largest proportion of oxide of iron should be the richest in gold, as they are.

"After all these deposits had been made, the hills were gradually thrown up, as in their present state, from under water. If the true fissure theory is correct (and it is the one most generally accepted by the most experienced miners), then there is reason to believe that the ore extends far into the bowels of the earth. And even if the theory

of an aqueous deposit or precipitation is accepted, the fields over which these deposits took place may have been so great that when turned up upon their edges they may be practically inexhaustible. These quartz veins between slate strata seem to be, in many respects, the analogies of the contact lodes of silver in Colorado, and may have had a similar origin.

"The quartz veins between porphyry walls have not been sufficiently developed to make it safe to give an opinion in regard to them. Some of the best mines of this class are situated in Strawberry Gulch, about seven miles east of Deadwood, and in some of them considerable bodies of ore have been found.

"In many of the placer mines, a little below the bed of the stream, but considerable above bed-rock, a layer of hard cement, consisting of sand, gravel, and boulders, and carrying free gold held together in one hard conglomerate mass by oxide of iron, has been found. This substance has been a great obstacle to gulch miners on some claims. They had no means of crushing it to free the gold, and to remove it in order to get at the auriferous gravel beneath was very expensive. On the hill-tops, which have withstood best the actions of the elements, similar cement deposits have also been found, varying from one and a half to twelve and eighteen feet in thickness. Some of them are very rich in gold and others very lean.

"A number of mines have been opened on the cement beds and are now working out their pay-ore. The rock is reduced in the same manner as quartz, by stamping and amalgamating. A cement deposit may be very valuable as long as it lasts, and may bring to its owner large profits, but its value depends entirely upon its extent and characLike a placer (and it is, in fact, nothing but a solidified placer) it will some day be worked out and become worthless."

ter.

Mr. White places the yield of the Black Hills mines in 1878 at $3,500,000; in 1879 at about $4,500,000; and in 1880 about $6,000,000.

CHAPTER II.

GOLD DIGGINGS.

In traveling through the Black Hills one will notice. along the numerous creeks vast piles of gravel. Through the midst of these heaps of pebbles, among which now and then there towers up the round back of a boulder, or rises a little grassy island, bearing some charred stump, one may often see remains of wooden machinery and the ruins of abandoned log cabins; or he may even meet with men at work, and learn how the hasty little stream is made to pause and pay toll in service as it rushes downward from the high cliffs where it was born.

All these appearances are signs of gold mining by the method known as "placer-washing" or "gulch-digging.' It is the simplest, and, in some respects, the most interesting of all the processes by which the precious metal is got out of the earth.

When gold has been discovered in any region (and this usually happens through some lucky accident), adventurous men rush to the spot and look for more signs of it. This search is called "prospecting," and it is done by parties of two or three, who go along the creeks flowing down from the hills, and test the gravel on the banks until they find what they seek. The prospector's outfit consists of as much provisions as he can carry on his back or pack on a pony, a couple of blankets, guns and ammunition, a few cooking utensils, a shovel and pick and a gold pan. The last is the most important after the provisions. It is made out of sheet-iron, and is shaped much like an extra large milk pan. The prospectors, who call each other partners or "pard" for short, agree to divide all they find; drudge along all day beside their ponies, keeping their eyes keenly upon the lookout, and slowly climbing toward the head of the ravine or gulch down which the creek flows. Finally they come to a point where the gulch widens out a little, or