378 Bibliographical Notice. 



varying from 1 to 30 feet in thickness : this seems to extend under 

 all the vast table-land to the northward, is thicker, more constant, 

 and more apparent towards the base of the mountains, but inter- 

 calates with the next deposit in some places. 2nd. The yellow marl 

 or Bluff-formation is favourable for agriculture ; consists of yellow 

 siliceous marl with calcareous concretions, and with pebbly clays at 

 the base ; sometimes attains a thickness of 300 feet, but is variable 

 over wide areas in the Missouri Valley. It seems to be locally syn- 

 chronous or continuous with the Drift, and is also, at places, seen 

 to succeed the Pliocene bone-bearing grits with imperceptible grada- 

 tions. It contains remains of recent Mammals, as well as of extinct 

 Mastodon, Elephas, &c, and large quantities of land and freshwater 

 shells, mostly, if not wholly, of living species. 3rd. Erratic blocks, 

 seldom exceeding four or five tons in weight, sometimes thickly 

 spread over large areas (in Dakota and Minnesota), sometimes form- 

 ing belts with a N.W.-S.E. range (near Fort Pierre and the Bijoux 

 Hills, on the Missouri (p. 110). 4th. Bottom-prairies, or the broad, 

 fertile, old alluvial flats of the Missouri, were formed under other 

 conditions than those now existing, which produce the present allu- 

 vium (No. 5), of which numerous islands, sand-bars, &c, are con- 

 tinually being made and re-made. A steamer wrecked fifteen years 

 ago has given rise to Pilot Island, near the mouth of the Platte, 

 several acres in extent, with a thick growth of cottonwood-trees, 

 from 12 to 20 inches in diameter. 



Lastly, the author briefly treats of the river-terraces, resulting 

 from the gradual elevation of the Rocky Mountains (p. 113). This 

 subject, with others referred to in this memoir, will be fully handled 

 in the forthcoming Report of Capt. Raynold's Expedition. 



Part III. (p. 138, &c.) comprises notes on the zoology and botany 

 of the Upper Missouri. Some interesting remarks are here made on 

 the Lynx, Wolves, Foxes, Beaver, Deer, Antelope, Mountain-sheep, 

 and Buffalo. Of the last we read (p. 150) — 



"The Buffalo are confined to the country bordering upon the 

 eastern slope of the Rocky Mountains. They occur in large bands 

 in the valley of the Yellowstone River, and also in the Blackfoot 

 country ; but their numbers are annually decreasing at a rapid rate. 

 Descending the Yellowstone, in the summer of 1854, from the Crow 

 country, we were not out of sight of large bands for a distance of 

 400 miles. In 1850 they were seen as low down the Missouri River 

 as the mouth of the Vermilion ; and in 1854 a few were killed near 

 Fort Pierre. But at the present time they seldom pass below the 

 47th parallel on the Missouri. Every year, as we ascend the river, 

 we can observe that they are retiring nearer and nearer the moun- 

 tainous portion. In Kansas, they are found at this time, at certain 

 seasons of the year, in immense droves on the Smoky Hill Fork of 

 the Kansas, within sixty or seventy miles of Fort Riley ; and from 

 there to the South Pass they are distributed to a greater or less 

 extent. It is true that these animals are at all times on the move, 

 and frequent different portions of the West at different seasons of 

 the year, or as they are driven by the hunters and Indians ; but 



