2 2 RAYMOND C. MOORE AND FREDERICK B. PLUMMER 



conglomeratic sandstones and alternating sandy shales. The 

 resistant beds in this portion of the section are beautifully exposed 

 over large areas in the Colorado and Brazos river valleys. 



The Canyon consists of massive limestones, from a few feet to 

 as much as 250 feet in thickness, alternating with shales. Although 

 commonly designated a limestone division, its character is in no 



LEGEND 

 hi: I Tertiary and Quaternary 

 K^'^ Cretaceous 



ITriassic-Jurassic 



] Permian 

 I I PENNSYLVANIAN 



I Undifferentiated Paleozoic 

 HH Pre-Cambrian 

 r**»1 Igneous 



Fig. I — Index geological map of Texas 



way comparable to the Bend, for in the Canyon, the limestones are 

 thinner and are interbedded with the shales. The limestones are 

 hard, fine-grained, in part very cherty, and are not as a whole very 

 fossiliferous. The shales are chiefly yellow to gray in color and 

 clayey rather than sandy. 



The Cisco is composed of thick shales and more or less con- 

 glomeratic sandstones, thin limestones, and some coal. The shale 



