1896. | NEW YORK ACADEMY OF SCIENCES. 107 
for a little distance but thence the surface becomes irregular 
and broken. Southwardly, the surface rises to the Ortiz moun- 
tains. 
Waldo station, where are the coke works of the Cerrillos 
Coal Company, is at the mouth of Coal canon; two miles above 
it, in the canon, is the village of Madrid, where one finds the 
Company’s offices. 
This area shows apparently all the workable coal beds of the 
Laramie, and probably contains the greater part, if not practi- 
cally all of the anthracite. It exhibits the gradations from 
bituminous to anthracite as well as some phenomena in struc- 
ture, familiar enough elsewhere, but previously unrecognized 
here. The student now finds better opportunities for investiga- 
tion than did the geologists already named, as the mining oper- 
ations have become extensive, and definite opinions can be 
reached concerning matters respecting which, under other con- 
ditions, only conjectures could be offered. 
Several mines have been opened in Coal canon, the most im- 
portant being in the immediate vicinity of Madrid; the Lucas, 
at the southerly end; the Cunningham, at the village,and the 
White Ash, immediately north from it. These are all on the 
upper or White Ash bed; two mines on the lower or Cook- 
White beds are within the village limits but are not worked.* 
GEOLOGICAL STRUCTURE OF THE AREA. 
No anticline occurs and the dip is almost east, N. 85° E., but 
on Coal canon, at about a third of a mile below the White Ash 
mine, the beds show very rapid northward dip for half a mile. 
Ordinarily the rate does not exceed 15° or 16°, but occasionally 
for a short distance it is much greater. 
No rocks older than the Laramie occur anywhere within the 
area under consideration except near Galisteo River, where beds 
of the Fort Pierre stage are reached. But great masses of 
trachyte, both as dykes and as intrusive sheets, form a charac- 
teristic feature of the anthracite area and extend to half a mile 
or more toward the west. 
The Eruptive Rocks.—The most southerly point visited is on 
Coal canon at probably four miles above its mouth, where one 
of the thinner coal beds was coked six or seven years ago. There, 
as clearly enough fora mile further up the canon, the easterly 
wall is capped by trachyte, 50 to 100 feet thick on the edge of 
* The writer is under many obligations to Mr. James Duggan, Superintendent, and 
Mr. Porterfield, Engineer of the Coal Company, for information which otherwise he 
could not have obtained. Mr. Charles J. Devlin, General Manager of Coal Properties 
of the Atchison, Topeka and Santa Fé Railroad Company, courteously furnished 
copies of the analyses of the coals. 
