1903.] Gidley, Fresh-water Tertiary of Northwestern Texas. 627 



The occasional beds of diatomaceous earth are easily ac- 

 counted for by supposing that there were in this ancient 

 valley occasional ponds filled with clear water, enduring for 

 various periods of time, partially or totally isolated from the 

 stream that ran through the valley, such as exist at the present 

 time in the West, especially in the Sand-hills country of 

 northern Nebraska and southern South Dakota. The diato- 

 maceous deposits are for the most part quite impure and con- 

 tain great quantities of remains of rushes and pond grasses, 

 indicating that these ponds were never of any great depth and 

 probably occasionally received an overflow from the stream 

 in times of freshet. 



Following is the list of species, as reported and determined 

 by Cope from the Blanco beds ^ and also as reported and de- 

 termined by the American Museum Expeditions : 



American Museum. 

 Testudinata. 

 Testudo campester. 



Edentata. 



Gly ptoiherium texanum-, 

 Megalonyx sp., 

 Mylodon sp. 



Carnivora. 

 Amphicyon (PBorophagus). 



Proboscidia. 



Dibelodon mirificus, 

 " tropicus. 



Perissodactyla. 



Neohipparion sp., 

 Pliohippus simplicidens. 



Artiodactyla. 



Platygonus bicalcaratus, 



" texanus, 



Pliauchcenia spatula, 



sp. 



' Rep. Geol. Surv. Texas, 1893, P- 73- . ,. ., _ . ^.. e>...,,„lva /,.,<• 



^ Equus simplicidens = Pliohippus stmplKtdens; Equus cummuisxt = Protoh^^^^ 



sp.?, and Equus minutus = Protohippus sp.? See Bull. Am. Mus. Nat. Hist., V0I..XIV. 



pp. 123-12S and p. 140.. 



Cope. 

 Testudinata. 

 Testudo turgida Cope, 

 " pertenuis Cope. 



AVES. 



Creccoides osbornii Schuf. 



Edentata. 

 Megalonyx leptostoma Cope. 



Carnivora. 

 Canimartes cuniminsii Cope, 

 Borophagus diversidens Cope, 

 Felis hillanus Cope. 



Proboscidia. 



Tetrabelodon shepardii Leidy, 

 Dibelodon huniboldtii Cuvier, 

 " tropicus Cope, 

 " prcecursor Cope. 



Diplarthra. 



Equus sim,plicidens Cope,^ 



" cumminsii Copc,^ 



" m,inutus Cope,^ 

 Platygonus bicalcaratus Cope, 

 Pliauchcenia spatula Cope. 



Total number of species, 16. 



