280 KANSAS CITY REVIEW OF SCIENCE. 
GEOLOGY- 
THE U. S. GEOLOGICAL SURVEY OF THE LEADVILLE MINING 
DISTRICT. 
The recent geological survey made by Prof. S. F. Emmons of the Leadville 
mineral district, has produced a marked change in opinion in regard to the 
extent of the mineral deposits of that camp, as well as to th^ nature and character 
of the deposits. His report for 1882, published by the Department of the Interior 
upon "The Geology and Mining Industry of Leadville, Lake Co., Colorado," has 
clearly and sharply defined the line of future investigation upon the subject. The 
effect of this valuable work in clearing the field of the numerous untenable theories 
that cumbered local investigation is just now becoming apparent in the direction 
and impetus it gives to exploration and development by mine-owners and opera- 
tors. With the facts given in his report before them, they go forward with a 
confidence hitherto unfelt. Every stone is a sermon of meaning instead of an 
enigma when studied in the light of the facts collated by him. In the maps ac 
companying his report he lays bare the surface of the rocks, and presents them 
as they exist hundreds of feet below the surface presented to the eye, showing 
the geological formation with its out-crops, dips, faults, breaks, and trends, so 
perfectly that it is fast becoming a chart to direct exploration and development. 
He has cut the mountains into sections, presenting the broken and disturbed 
present condition of the strata, in contrast with the natural stratification existing 
before the great upheaval. With these maps and accompanying explanations the 
displacements in the formations so often occurring, no longer puzzle the miner. 
But the most important feature of Prof. Emmons' work is in demonstrating 
the extension and existence of the mineral bearing formation to the south of the 
present producing area as far as Weston's Pass, and to the west under the City of 
Leadville to the Arkansas River. This he declares in the naturally cautious- 
words of a scientific man, but his language leads by inference irresistibly to that 
conclusion. And recent developments in the territory lying south of Iowa Gulch 
and on either side of Empire Gulch have proven the correctness of his statements. 
No one can ride over the territory lying south of Iowa Gulch, as the writer has 
done, and note the exact likeness of the geological formation to that of the ]jro- 
ducing area adjoining it on the north, and see the great outcrops of iron-lime- 
stone, the exact counterpart of those on Fryer, Carbonate, and Iron Hills, with- 
out being impressed with the conviction that the slopes of Empire Gulch will 
soon develop into a second carbonate camp as busy and fruitful as the one at 
Leadville, adjoining it on the north. 
