396 N. It. DARTON — CATALOG OF PHOTOGRAPHS 



364. Calcareous tufa bank, Cement creek, Gunnison county, Colorado. Face 



seen is 40 to 50 feet high, overhanging in places, forming grottoes (No. 11). 



365. Calcareous tufa deposit, near view of central portion of bank shown in No. 



364 (No. 12). 



366. Eastern part of San Miguel mountains, Colorado. The sharp peak of mount 



Wilson (14,000 feet) is of diorite cutting up through Cretaceous and Eocene 

 strata (No. 197). 



367. Mount Wilson group, San Miguel mountains, Colorado. The smooth slopes 



of middle ground are of Cretaceous shales. The canyon in foreground is 

 cut below the Dakota sandstone (No. 198). 



368. Western portion of San Miguel mountains, Colorado. The sharper points 



are denuded laccoliths in Cretaceous shales. The plateau seen extends 

 westward into Utah (No. 199). 



369. Mountains north of the San Miguel river, near Telluride, Colorado. The 



lighter colored band of strata belong to an Eocene (?) conglomerate. 

 Above it 2,500 feet of andesitic tuff and bedded breccia. Forms pano- 

 rama with No. 370 (No. 205). 



370. Mountains north of the San Miguel river, near Telluride, Colorado. Dallas 



peak (13,700 feet). Forms panorama with No. 369 (No. 206). 



371. Mount Sneffels, San Juan mountains, Colorado (14,000 feet). A great diorite 



and gabbro mass cutting up through andesitic tuffs and breccias. Tertiary 

 (No. 210). 



372. A characteristic cliff of fine grained andesitic tuff. Bridal Veil basin, near 



Telluride, Colorado (No. 217). 



373. South Lookout peak, near Ophir, San Juan mountains, Colorado. Char- 



acteristic cliffs and pinnacles of coarse bedded andesitic breccia and tuff 

 (No. 222). 



374. Iron spring near Ophir, Colorado. The spring has built up a terrace of red- 



dish, sinter-like materials, as about the Yellowstone hot springs (No. 225). 



375. The Twin Sisters peaks, San Juan mountains, Colorado. Jurassic strata 



form smooth slopes of middle ground ; an Eocene (?) conglomerate, the 

 cliff next above ; Tertiary tuffs the peaks proper. Forms panorama with 

 No. 376 (No. 231). 



376. East of Twin Sisters peaks (forming panorama with No. 375). Triassic con- 



glomerate causes cliffs of foreground. Eocene (?) conglomerate lies uncon- 

 formably on Cretaceous, Jurassic, and Triassic strata on farther side of 

 central valley (No. 232). 



377. Vermilion peak, San Juan mountains, Colorado (13,700 feet). Typical cliffs 



of bedded breccias and tuffs. Ehyolite flows cause summit cliffs (No. 236). 



378. La Plata mountains, Colorado ; looking up Boren gulch from the southeast ; 



Babcock and Spiller peaks in the center ; the peaks mainly made up of a 

 diorite stock cutting Mesozoic strata. An irregular diorite-porphyry body 

 causes jagged cliffs on the left side of Boren gulch (No. 262). 



379. Cliffs at the head of Bedrock gulch, La Plata mountains, Colorado ; forma- 



tion of cliffs is La Plata Jurassic sandstone, much indurated (No. 268). 



380. A ravine at the head of Bedrock gulch, La Plata mountains, Colorado. The 



rock here is much shattered and highly altered diorite-porphyry (No. 270). 



