564 THE JOURNAL OF GEOLOGY. 



present or past. The Equus beds of the Llano Estacado are sim- 

 ilarly related to the underlying Blanco beds, and in one instance, 

 on Wild Horse creek, rest directly on the Trias. In addition to 

 the typical locality at San Diego, these beds are found at many 

 other localities on the Coastal slope, some of which have been 

 noted in the publications of Cope and Leidy and others by this 

 Survey. They also extend up the river valleys for considerable 

 distances, as is proved by the presence of characteristic fossils 

 from the second bottom deposits as far inland as Austin. The 

 species described from the Plains are as follows : 



Testudo hexagonata Cope ; T. laticaudata Cope ; Mylodon ? 

 soda/is Cope; Eleplias primigenius Blum; Equus excelsus Leidy; 

 E. semiplicatus Cope ; E. tau Owen ; E. major Dekay ; Holem- 

 eniscus sulcatus Cope ; H. macrocephalus Cope. 



From the San Diego beds the following have been reported : 



Cistudo marnockii Cope ; Eleplias primigenius Blum ; Ca?iis sp. 

 Glyptodon petaliferus Cope ; Equus tau Cope ; E. semiplicatus Cope; 

 E. excelsus Leidy ; E. occidentalis Leidy ; E. crenidens Cope. 



In addition to these many others have been reported from 

 localities to the eastward, proving the existence of the beds over 

 a large portion of the Coastal slope. 



The shells collected from the upper part of the San Diego 

 beds and determined by J. A. Singley are as follows : 



Bulimulus dealbatus Say ; Physa gyrina Say ; P. heterostropha 

 Say ; Patula alternata Say ; Planorbis lentus Say ; P. bicarinatus 

 Say; P. parvus Say; Amnicola per acuta P. & W.; Unio texasensis 

 Lea ; U. sp.? , Splicerum elevatum Hold. ? ; Helicina orbiculata Say ; 

 Helix texasiana Mor. 



Coast clays. — The Coast clays which are regarded as the west- 

 ern extension of the Port Hudson group of Hilgard, and as 

 belonging to the Champlain Period of Dana, underlie the greater 

 part of the area of the coast prairies. They form a wide belt 

 lying between the Reynosa and the sandy coastal strip, and in 

 many places stretch to the very shores of the bays which border 

 the gulf. 



The Coast clays are for the most part heavy limy clays of vari- 



