1899-] Mattheiv, Fresh- Water Tertiary of the West. 2 1 



Notes on the Lake Basins. 



San Juan Basin. — In northwestern New Mexico, on the divide 

 between the Rio Grande and San Juan Rivers. The beds con- 

 formably overlie the marine and brackish water Cretaceous 

 (Laramie), and contain fossils confined in the Basal Eocene to 

 three strata, two at the bottom of the Puerco beds, one in the 

 Torrejon. The Wasatch is sparingly fossiliferous throughout.' 



Big Horn Basin. — \\\ northern Wyoming. No weighty faunal 

 distinctions have been shown to exist in this great mass of sedi- 

 ment, which is sparingly fossiliferous throughout. Buffalo Basin 

 is a subordinate basin, apparently somewhat later than the main 

 basin. ^ 



Wind River Basin. — \\\ central Wyoming. Fossils are rather 

 scarce in this basin. All the sediments are later than the Wasatch 

 and earlier than the Bridger.^ 



Huerfano Basin. — \x\ southern Colorado. Osborn has recently 

 shown that the Wind River is represented here as well as the 

 Bridger. There are also overlying sediments of ? Pleistocene age.* 



Upper Green River Basin. — \\\ southern Wyoming. This in- 

 cludes the Bridger and Washakie, with Middle Eocene fossil 

 mammals, and much larger areas where Green River (= Wind 

 River) and Vermillion Creek (= Wasatch) sediments are the only 

 beds not washed away by the extensive erosion which has taken, 

 place. The Vermillion Creek sediments contain fossil mammals 

 in a few localities (Evanston, Black Buttes, etc.), while the Green 

 River shales contain fossil fish in abundance.^ 



Uinta Basin. — In northeastern Utah. The Middle and LTpper 

 Eocene beds are underlain by a considerable thickness of sedi- 

 ments, probably of Lower Eocene age, in which no fossils have 

 been found. The three fossiliferous horizons are : C, the Upper 

 or True Uinta, explored for fossils by Marsh in 1870 and the 

 Princeton party of 1886 ; B, the Lower Uinta or Telmatotherium 

 Beds ; and A^ probably equivalent to the upper part of the 

 Bridger. The last two horizons were discovered by the American 

 Museum Expedition of 1894.'' 



1 Authority, Wortman. See Bull. Amer. Mus. Nat. Hist., 1892, 135; 1897, 259. 



2 Authority, Wortman, Bull. Amer. Mus. Nat. Hist., 1892, 135. 

 ^ Authority, Wortman, /. c. 



* Bull. Amer. Mus. Nat. Hist., 1897, 247. 



^ Authority, Hayden Survey Reports, etc. Also Wortman (communicated). 

 " Authority, Peterson, Bull. Amer. Mus. Nat. Hist., 1895, 72 ; Marsh, Amer. Jour. Sci., 

 March, 1871. 



