THE CENOZOIC DEPOSITS OF TEXAS. 56$ 



ous colors, yellow, red and blue in places, in others olive green and 

 brown. They are interbedded with sand, contain nodules and con- 

 cretions of lime, are often high in iron, and the sand, which for 

 the most part is uncompacted, at times forms concretionary masses 

 of considerable size. These clays vary from east to west in accord- 

 ance with the varying character of the beds from which they were 

 derived, being more silty eastward and denser toward the west. 



In the only contact of any extent which I have seen, that on 

 the Brazos river east of Sealy, the Coast clays rest unconformably 

 upon the Equus beds, as they do upon the Reynosa further west, 

 in such places as the Equus are lacking. In them have been 

 found several varieties of land shells, and fossil vertebrates occur 

 at many localities. They too, stretch inward for many miles 

 along the river channels forming the second bottoms, and even 

 the highlands, as proved by the fossils secured from such deposits. 

 These are usually characterized by ElepJias and Equus remains. 

 Similar remains as well as those of smaller animals, are also 

 found in the body of the deposit itself. 



These clays have been studied very little. The exposures are 

 so very few and usually so widely separated, the fossils so scat- 

 tered, and the economic questions outside artesian water and 

 agriculture, so few, that they have not received the attention 

 they deserve. It seems probable, however, that when more 

 thoroughly studied, they will be separable into two portions, the 

 lower being much darker and more evenly bedded than the 

 upper or massive beds. 



The evidence before us now, however, is to the effect that the 

 second bottoms of the rivers are by no means referable to any 

 one division either of the Pliocene or Pleistocene, but that they 

 comprise deposits ranging in time from Blanco to Recent. 



Either to this or to the upper Equus horizon must also be 

 referred the brown silty clay which is found on some of the 

 divides in the Coastal slope. In places this carries land shells 

 and exhibits a loess-like structure. It is well developed on the 

 divide between the Nueces and the Leona, and has been observed 

 in many other localities. 



