OF NORTH AMERICA. 
31 
The Organ mountains are celebrated for their rich mines of argentiferous lead, of whicii you 
haA'e collected magnificent specimens. 
As regards the constriiclion of a railroad, the rocks between Delaware creek and El Paso are 
very favorable. There are sandstone, limestone, granite; and it is probable that in choosing the 
points, artesian wells could be established with success by selecting the Carboniferous limestone, 
or the While Sandstone, for the operation. 
Accompanying this will be found a rough sketch of a geological section of the country tra- 
versed by the survey, which I have made as complete as possible, not having gone over the 
ground myself. 
Captain John Pope, 
Corps Topographical Engineers, United Slates Army. 
JULES MAHCOU, 
Geologist and Mineralogist. 
•) This geological profile was published on the margin beneath the map of Ca|)t. Pope with the title : 
Profile of the route from El Paso to Preston. (See: Map of the Surrey of a route for the Pacific railroad 
near the 32'' Parallel between the Rio Grande and Red River, by Capt. John Pope assisted by Lieut. K. 
Garrard. Washington, 10 Febr., 18.55.) 
