360 KANSAS CITY REVIEW OF SCIENCE. 



portion being consumed by the Pueblo Iron Works, the ore being of a quality- 

 known as "magnetic iron ore" from which the best of Bessemer steel rails are 

 manufactured, and a superior quality of nails is made that has practically driven 

 all eastern nails out of market. 



But the greatest expense and labor has been in determining where were the 

 deposits of silver and gold of sufficient richness to justify working. The State 

 has an area of 104,000 square miles, and a hundred times more difficult of ap- 

 proach in its natural condition than a level or rolling country. 



The passion for discovery was never more intense in the breast of Cortez 

 than has filled the hearts of Colorado prospectors since 1874. A mere handful 

 of men, exceeding at no time, perhaps, over 15,000 active workers, they have 

 hewn through flinty granite and porphyry the royal roadways to wealth, that now 

 intersect with a splendid system nearly every mountain and gorge of this enchant- 

 ing domain. Throughout the whole State towns and cities are built provided 

 with all the demands for comfort. The area for profitable mining has commenced 

 since the labor and sacrifice of preparation is over. Years ago the area of min- 

 ing in Colorado was measured by the league or square mile — now the eye can 

 trace its boundaries at any given point. 



The really valuable mining ground in any country is much less than is gen- 

 erally supposed. At Leadville, if it were collected together along the entire car- 

 bonate belt extending for fifty miles or more, it would not exceed five miles 

 square. The mines at Red Cliff, thirty miles north of Leadville, which have 

 produced for the last three years 100 tons per day of marketable ore, are found 

 upon Battle Mountain within a radius of a half or three-quarters of a mile. That 

 whole country bordering and west of the Arkansas Valley, reaching over as far as 

 the Gunnison country, shows silver and gold, and may been mentioned as a min- 

 ing country, yet profitable mining can only be prosecuted in small patches of 

 ground and only a few mines contribute to give the several districts a character 

 and name abroad. Yet the possibilities of these patches of rich mineral deposits 

 are beyond all calculation. In the great San Juan those localities which first 

 attracted attention and led to the rapid settlement of the country, are little farther 

 advanced than they were in 1875, 7^^ small areas of very rich ores are now deter- 

 mined and new and valuable points are ascertained, and San Juan now presents 

 a larger and better known field for profitable mining than can be found in any 

 State or Territory outside of Colorado. 



The only profitable mines in the Red Mountain district, which is really a 

 new Leadville in richness, are found within an area of one mile square. Cross- 

 ing the range to the north of Red Mountain you find Marshall Basin, which has 

 the largest area of rich, paying ores in the State, it being about three miles from 

 the head of the basin to the San Miguel Valley, and paying mines are found with 

 almost unbroken regularity upon the northern slope of the basin and a few in the 

 center and upon the sounthern slope. Between Marshall Basin and Ouray — a 

 distance of sixteen miles — the real rich ores that can be developed profitably are 

 found in small scattered areas. 



