130 Cincinnati Society of Natural History. 
miles, near Agate lakes, north of the Sweetwater. All of them are 
water-worn. Itis an accepted fact that the “ moss’’ in agates is but 
the result of impeded crystallization. The best exposures of the Plio- 
ocene series are low down on the Sweetwater, and along the northern 
edge of the plateau. The thickness is estimated at from 700 to 900 
feet. 
The Wyoming Conglomerate is structureless, and composed of the 
most varying material. It is the product of all formations existing 
within a given area. Along the entire northern slope of the Sweet- 
water and Seminole hills there are enormous deposits of it. The thick- 
ness is estimated at from 10 to 400 feet. It is also abundant along the 
southern slope of the: Sweetwater mountains, in the Pliocene valley 
west of South Pass, and is scattered to a greater or less extent all over 
the country, which has been subjected to extensive erosion. The 
maximum accumulation occurs along the shores of the former Ter- 
tiary lakes, and was probably carried there by the waters draining in- 
to them, and it is, therefore, of the age of the younger Pliocene marls 
and shales, 
George M. Dawson* said that in the plateau region in the southern 
part of British Columbia, lying east of the Coast Ranges, terraces are 
exhibited on a scale scarcely equaled elsewhere. They border the 
river valleys, are found attached to the flanks of the mountains to a 
great height, though none have been found in this region equal to the 
elevation of that on Ilgachuz mountain in the north—5,270 feet. The 
higher terraces can be due to nothing else than a general submergence 
of the country. Five of the best marked terraces on the southern 
slope of Iron mountain, at the mouth of the Coldwater, have the follow- 
ing elevations above the sea, viz: 2,386, 3,063, 3,392, 3,611, and 3,715 feet. 
The last mentioned is the highest observed, and is quite narrow. 
Above this, the drift covering becomes thinner, but rolled stones, some 
of them certainly from a distance, occur to the very summit—sd,280 
teet above the sea. The elevation of the white silt terrace bordering 
Okanagan lake, is 200 feet above the lake, or 1.277 feet above the sea. 
Leaving this to ascend the Okanagan mountain, south of the Mission, 
a great series of high terraces is passed over. The heights of six of 
these are as follows: 1,862, 2,042, 2,141, 2,645, 2,800, and 2,839 feet. 
On the northern slope of the same mountain, six principal terraces 
have the following heights: 1,451, 1,579, 1,962, 2,452, 2,553, and 2,879 
feet. 
* Geo. Sur. of Canada. 
