628 PROCEEDINGS OF WASHINGTON MEETING. 



282, 233, 234. Mato Tepee, Wyoming. Plug of columnar volcanic rock exposed by- 

 erosion. Height of column above the river, about 1,100 feet. 



Craters^ Table Mountains, Peaks atid Doynes. (Size, 8 x 10 inches.) 



235. Mono crater, Mono valley, California, from the south. Photographed by I. C. 



Kussell, 1883. 



236. End of Obsidian flow, Mono craters. Mono valley, California. Published in 



Eighth Ann. Rep. U. S. Geol. Survey, pi. XLIIL Photographed by I. C. 

 Russell, 1883. 



237. Mount Wilkinson (or Table mountain), Gunnison county, Colorado. A remnant 



of a complex basalt sheet, resting upon Cretaceous sandstones. " Mesa " type 

 of mountain. Photographed by C. Whitman Cross, July 25, 1885. 



238. Castle rock, near Golden, Colorado. A point projecting from the basalt sheet of 



Table mountain. Represents a confused mingling of dense and scoriaceous 

 lava, presumably near edge of flow. Photographed by C. Whitman Cross, 

 1886. 



239. Mount Wheatstone, Gunnison county, Colorado (12,543 feet). Upper two-thirds 



of mountain a single mass of coarse porphyry, a laccolite from which all over- 

 arching strata have been eroded away. Glacial amphitheatres in upper part. 

 Photographed by C. Whitman Cross, October 15, 1885. 



240. Teocalli mountain, West Brush creek, Gunnison county, Colorado (13,220 feet). 



Structure caused by beds of Carboniferous rocks, much metamorphosed by a 

 large diorite mass behind the mountain. Photographed by C.Whitman Cross, 

 October 4, 1885. 



241. Typical scenery in the Elk mountains, Gunnison county, Colorado. Pearl 



mountain in the center, 13,484 feet. Brush creek valley. Timber line at 

 12,000 feet. Photographed by C. Whitman Cross, October 2, 1885. 



242. Glaciated dome in Tuolumne valley, California. Photographed by I. C. Rus- 



sell. 



MISCELLANEOUS. 



Columbia and Potomac Formations. (Photographed under the direction of W J 

 McGee by C. C. Jones, 1886. Size, 10 x 13 inches.) 



Nos. 243, 244, 245, 246, 247, 248, 249, 250 are published in the Seventh Ann. Rep. 

 U. S. Geol. Survey, with plate numbers as below. 



243. Wild Duck blufi-. PI. LXI. 



244. 245. Unconformity between Columbia and Potomac formations. Pis. LXIII, 



LXIV. 



246. Turkey point. PL LXV. 



247. Southeastern extremity of Grove point. PI. LXVI. 



248. Center of Grove point. PI. LXYII. 



249. Upper terrace at Ordinary point. PI. LXXI. 



250. Section at Howell's point. PI. LXIX. 



251. Near East Capitol street, between Sixteenth and Seventeenth, Washington, D. 



C. Columbia loam, as excavated for brick-clay, and terrace plain formed by 

 it. Natural surface. Looking southwest. 1887. 



252. Columbia and Potomac formations, Forest place, north side of Chase street, 



Baltimore, Maryland. 1885. 



253. Formation of gravel from vein quartz. South side of Oakland street, 200 yards 



west of Columbia road, Kalorama heights, Washington, D. C. 1888. 



Exj^erbnents of Bailey Willis in 1890 in Folding Loaded Strata by Horizontal Thrust. 

 The photographs in series 254 to 284, inclusive, are part of a series representing 

 models of folded strata. 



