Geologists have found it difficult to ascertain the precise extent of the great mineral belt of Colorado, but it is believed that useful minerals will be found abundant in nearly every section in the Rocky Mountains where the out-croppings of the gneissic and granitic rocks occur. The principal mining operations have been conducted in the counties of Gilpin, Clear Creek, Park, Summit, Lake, and Boulder, embracing a belt from 30 to 60 miles wide. The richest silver mines developed are in the vicinity of Georgetown, and the gold mines which have produced the richest ore are in the several vicinities of Gold Hill, Black Hawk, Central, and Nevada.

In the mines of Colorado the gold ore rarely exists in considerable quantities without an intermixture of more or less silver, or the silver without tracings of gold and copper, and frequently even in the richest mines of the Territory all three metals are combined in the same ore. The placers are distributed over a large extent of country, and continue to yield handsome returns. Water is generally abundant, and, with every natural facility for working the placers, it is probable that they will present a fine field for years for well-directed enterprise. The surveyor general estimates the product of the placers of Colorado during the last fiscal year at $1,500,000. The mining interest has been finally established upon a permanent and substantial basis, and is a separate branch of industry. It is regulated by science and capital, and the product of the gold and silver mines promises soon to equal that of the most promising days of the placers. The surveyor general esti mates the coin value of the mineral product of the quartz mines for the year ending June 30, 1870, at $2,500,187; the value of improvements at 86,102,460 in coin; and the value of capital employed in this branch of industry, at $2,362,660 in coin.

Since the date of last report many important discoveries have been made for the treatment of ores at reduced cost, which will thus bring large quantities of low-grade ores to the mills which have been heretofore regarded as of no practical value. The surveyor general reports the cost of mining and delivery of the ore on the surface at $4 per ton, hauling, $125 per ton, and milling, $2 50 per ton; the total cost thus reaching $4 75 per ton.

Copper is not found in a native state in large quantities, but exists in the form of pyrites distributed throughout the gold and silver mining districts, and in the mountains surrounding the North, Middle, and South Parks. Copper glance is met with near Idaho City, in Clear Creek County, at Pleasant View, and in other localities.

Lead occurs principally as an argentiferous galena, and is found in juxtaposition with gold and silver; but, like copper, this metal has not been mined except for fluxing in the process of smelting other ores. The most extensive deposits of galena occur in the lodes in the vicinity of Georgetown, where it yields to the ton from 100 to 600 ounces of silver.

Iron pyrites occur throughout all the mines of Colorado in cubes and pentagonal dodecahedrons. Micaceous iron ore occurs in Elk Creek in fine crystals like mica; specular iron ore on the Cache la Poudre, St. Vrain River, and in some other localities. Spathic iron ore abounds in the vicinity of Georgetown; titanic iron ore, near Central City, and hydrated oxide of iron is frequently met with at South Boulder, Golden City, as well as in other localities, while red and brown hematite occurs in abundance in the vicinity of the deposits of coal. Zincblende is found in the mines around Georgetown and Nevada City.

Large areas of the plains of Eastern Colorado are underlaid with lig

nite and coal, which also exists along the base of the mountains and in the parks. The survey of the northern boundary of New Mexico in 1868 revealed the existence of vast deposits of bituminous coal in the southern part of Colorado, in the vicinity of the Raton Pass, and in numerous localities from the San Luis Valley to the west boundary of the Territory. Near the Rio la Plata it is spread over a large area, 80 acres in one place being exposed. It is found in the valley of the Purgatory River, from Trinidad to the source, in almost one continuous line of out-croppings. The coal mines which have been the most extensively developed occur in the older settled portions of Colorado, in the counties of Boulder, Jefferson, Arapahoe, and Douglas. The Marshall mine of South Boulder Creek is the most valuable and extensive deposit of tertiary coal which has yet been developed west of the Mississippi River. Cannel coal of good quality has been discovered on the Rio San Juan and the Rio la Plata, and Albertine coal, or solidified petroleum, is reported on White River, in the western part of Summit County, several feet in thickness, and reported as extending over more than a thousand square miles. There are also many other minerals scattered throughout the Territory of greater or less commercial value and interest to sci

ence.

The

A large area of Colorado is yet but imperfectly explored. Thirty miles west of Denver, at the town of Idaho, in Clear Creek County, there are warm springs of some celebrity, and at which several large hotels and bath-houses have been erected for the accommodation of invalids and others. The water varies in temperature from 80° to 100° F. in the different springs. There is a remarkable soda spring in Current Creek, in Fremont County, 31 miles northwest of Cañon City, situated on the apex of a conical hill 100 feet in diameter and 40 feet high. flow of the spring is insignificant, but the water is of the strongest solution. Several springs of the same character exist at Cañon City, the waters of which are quite palatable, and are drank habitually by the inhabitants of that vicinity. In the vicinity of Soda Creek rich deposits of gold have been discovered, but the miners have been unable to reach the bed rock in consequence of the heat, which increases rapidly after reaching a few feet below the surface. The use of the water, both internally and externally, is highly beneficial in rheumatic and other kindred diseases. There are soda springs ten miles southwest of Denver, from which a small amount of soda is manufactured. It is reported that they are capable of producing three tons of crude soda per day, suitable for chemical and mining purposes. A short distance from the soda is a small white sulphur spring. Several alum springs exist in the same neighborhood, in and around which crystallized alum is found by digging. Late geological reconnoissances in Colorado have revealed the existence of soda lakes and springs, which are regarded of importance. They occur in the metamorphic rocks, twelve miles southwest of Denver, between Turkey and Bear Creeks, covering considerable area. The incrustation on the water has the appearance of discolored ice, while the earth surrounding is impregnated with soda. The water contains 20 per cent. of soda, while the earth contains 33 per cent. of the salts. Soda springs, or boiling fountains, as they are termed, occur on Fountain Creek, three miles above Colorado City, in El Paso County, at the northeastern foot of Pike's Peak. An analysis of the waters shows they contain carbonate and sulphate of soda, chloride of sodium, sulphide of calcium, and small traces of magnesia. These salts exist in abundance and constitute an important article in the manufacture of glass, with silicic.acid, as well as in the refining of gold and silver when used in

the form of bicarbonate of soda. The water is very cold, and comes up with a bubbling sound, gas escaping on both sides of the stream and in its bed. The water is quite palatable when taken as an effervescent beverage with acid and syrup.

The South Park Salt Works are situated southwest of Fair Play, the springs covering fifty acres. They have been worked heretofore to some extent by furnace evaporation, producing as high as two tons a day, at a cost of nearly $50 per ton. It is estimated that these springs discharge enough brine to yield daily at least forty tons of salt. These works have lain idle since the completion of the railroads in Colorado, as salt can be purchased in other localities and shipped to the Territory at a less cost than it can there be produced. There are several other small salt springs and a white sulphur one in the same locality. Salt occurs in several localities in a comparatively dry state. All grades of it find a ready home market for mining, grazing, or domestic purposes. A mineral spring is reported in the northwestern part of Lake County, west of the Arkansas River, the waters of which in taste resemble some of the mineral spring waters at Saratoga, New York. Of the mineral springs of Colorado those charged with sulphur are the most important and abundant. Probably the most valuable of this class is the hot sulphur spring in the Middle Park, near the right bank of Grand River, and forty feet above it, breaking out from a hillock of near that height formed by deposit from the water. There are several springs near at hand, evidently from the same source, forming one stream or brooklet of forty inches, and uniting with Grand River. The temperature of the water at the outlet ranges from 109 to 116° F. Besides white sulphur, the water shows iron and magnesia, while the deposits around the spring contain gypsum and sulphur. No analysis of the water has been reported. A basin in the rock forms an admirable natural bath, and the waters when applied externally are found wonderfully efficacious in rheumatic and scrofulous. diseases and for bruises and sprains. On the opposite side of the river there is a small white sulphur spring. Springs of the same character are found 75 miles to the northwest, on the headwaters of White River. Hot sulphur springs have also been discovered on Grand River, near the mouth of Roaring Fork, 100 miles southwest of those mentioned in the Middle Park. The Pagosa Spring is on the Rio San Juan, just north of the south boundary, near the one hundred and third degree of longitude west from Greenwich, close to the base of the San Juan Mountains, at an altitude of 7,000 feet above the level of the sea. It is situated on the low lands, 200 yards from the river, and is 80 feet long and 50 wide. The earth near the edges is covered with incrustation from two to four inches thick, composed mainly of sulphur and iron, perforated, and having the ap pearance of pumice stone, but possessing the solidity of marble. The water has a bluish cast, boiling up in the center, with a heavy bubbling sound, in a column fourteen inches high and two feet in diameter, where it has a temperature of 200° F., being cooler at the surface on the outer edges. When sufficiently cooled for drinking purposes it is found quite palatable, resembling Congress water. The waters of this spring, containing sulphur and iron, are reputed to possess great curative qualities, and are the resort of Mexicans and Indians for hundreds of miles. a distance of 300 feet around this spring the earth is perforated, and a sulphurous vapor constantly issues through apertures of various sizes. The Indians and Mexicans procure vapor baths by wrapping themselves in blankets and prostrating themselves upon the ground over these apertures. This spring, standing at the foot of a high mountain, in the midst of pure, fresh mountain air, and surrounded by magnificent

For

scenery, possesses many natural advantages for a great fashionable resort in the future settlement of that part of the country. Several sulphur springs here occur along the Rio Navajo, and in other places in the southern border of the Territory. A cluster of hot white sulphur springs, some of which are highly charged, occurs near the western side of the South Park, in Lake County, along the banks of Chalk Creek, a stream entering the Arkansas from the west. Again, near the Raton Pass, between the Arkansas River and San Luis Park, another very large sulphur spring exists, the waters of which reach a temperature of 100° or 105° F. A fine magnesian spring has been discovered at the base of a high mountain on the Rio La Plata, in the southwestern portion of the Territory.

Colorado is preeminently a mining region, its mineral wealth hav ing attracted the largest portion of its present population. It is, therefore, but recently that special attention has been given to the culture of the soil, and hence we have in this report comparatively meager data; still, sufficient is known to make it apparent that, by proper culture and irrigation, many of the choicest fruits, vegetables, and cereals of the north temperate zone can be grown here. Of the cereals, wheat, oats, barley, and corn grow in perfection. Wheat has been grown throughout the length of the Territory, from north to south, in San Luis Park, south of the Arkansas, and nearly all along the Arkansas, North Platte, and South Platte, and their branches. Thus far spring wheat has been almost exclusively cultivated, in view, mainly, of the difficulty in preparing the ground in autumn for sowing winter wheat. All the varieties which have been sown grow well and represent their sev eral peculiarities, but the White Sonora is the most highly prized, on account of the beautiful white flour it makes and its heavy yield. The measured bushel of Colorado wheat will weigh from 62 to 64 pounds. The wheat grown in Colorado is claimed to have the same peculiarities as that of the Pacific coast-to require to be moistened before grinding, to yield more flour than the same bulk or weight of wheat grown in the East, and to bear transportation to any part of the world without damage from climatic influences. Oats yield abundantly and are raised with ease. The demands for barley have not been such as to induce the culture of large crops, but so far as it has been tried it produces well. Rye and corn produce good crops, but the yield is not quite equal to that of the Eastern States or the Mississippi Valley. The culture of potatoes and all other root crops, as well as melons and the most common kinds of vegetables of the same latitude, both east and west, has been attended with the most satisfactory results. There is reason to believe that all the hardier, and perhaps other, fruits may be here raised successfully.

Orchards have been planted in the valley of the South Platte and Upper Arkansas, the experiments, so far as reported, having, in the main, proved satisfactory. The subject of planting forest trees upon the treeless plains in Eastern Colorado, where timber is deficient, has engaged the attention of but few settlers as yet, but the feasibility of this matter has been demonstrated in the fine grove of cottonwood now growing luxuriantly in the city of Denver.

The surveyor general, in his annual report, estimates the average yield of crops in the Territory as follows: Wheat, 30 bushels; oats and barley, 35 bushels; corn, 30 bushels; and potatoes, 100 bushels per acre. It is common among farmers to produce, with the aid of irrigation and proper culture, 60 bushels of wheat, 80 bushels of oats, and 70 bushels of barley, demonstrating the great fertility of the soil and the benefits.

derived from irrigation as an offset against the additional expense incurred in its use. All kinds of grain which can be produced in the same latitude east can be raised in perfection, with the aid of irrigation. Melons and vegetables attain enormous proportions and at the same time retain the tenderness, sweetness, and juiciness of the smaller growth in other sections. Wild fruits are everywhere abundant and delicious in flavor. The crop of 1869 was larger than that of the year 1868, and has been placed at 675,000 bushels wheat, 600,000 bushels corn, 550,000 bushels oats and barley, and 350,000 bushels of potatoes and other root crops, which, with the hay and dairy product, is estimated to possess a market value of at least $3,500,000. The present season has been here one of unparalleled productiveness, it being estimated that the aggregate agricultural product of Colorado for 1870 will be much greater than that of any preceding year, and its market value correspondingly enhanced. The surveyor general estimates the whole area in cultivation in the Territory at 63,463 acres, of which, during the pres ent year, 22,750 acres were sown in wheat, 12,571 acres in oats, 3,142 acres in barley, 20,000 acres devoted to the culture of corn, and 5,000 acres to the production of potatoes and vegetables. It will be observed that this estimate does not include lands devoted to grazing, dairying, and to the growth of grass for hay, which would probably swell the area to 200,000 acres. While the agricultural interests of Colorado show every indication of thrift and rapid development and expansion, it must remain subordinate to the grazing interest, which promises for all time to come to prove the second great source of wealth in the Territory. A very large area of this region, including extensive tracts of the gravelly plains, the mountain slopes, and foot-hills, as well as many portions of the valleys, possesses peculiar advantages for sheep and wool growing. This interest has already attained considerable importance. The surveyor general estimates that of the wool clip of this year at least 2,000,000 pounds have been shipped to the eastern markets alone. The amount required to supply the local demand would proba bly increase this amount by several hundred thousand pounds. The rich indigenous pastures afford an abundant supply of food throughout the year. Shelter is not generally needed during the winter, so that sheep can be kept at a trifling cost. In this congenial climate they multiply with great rapidity and the fleeces exceed in weight and quality those of similar breeds in other localities. Besides, the various diseases incident to the crowded pastures and folds of the East are rarely met with. These cir cumstances cannot fail to place this region, at no distant day, among the first wool-growing districts in the United States. The raising of horses, cattle, and mules is attended with the same facility as sheep-growing, and each of these interests is daily increasing in importance.

The increased facilities of communication and transportation, both east and west, will tend to stimulate grazing industry. A few years ago beef cattle were driven from California into Colorado to find a market, the latter region not then producing sufficient beef to supply local demand. Since the completion of the railroads to the Pacific, large shipments of cattle have been made from Colorado to supply the market of California.

Since the date of last report the Kansas Pacific Railroad, from Kansas City, Missouri, to Denver, the Denver Pacific, uniting Denver with Cheyenne, on the Union Pacific Railroad, and the road between Denver and Georgetown, have been finished and are in operation. The completion of these roads, which connect with the grand railroad system of the