\<^o-^,?[ Gidley^ Fresh-water Tei'tiary of Northwestern Texds. 625 



4. White diatomaceous earth 8 feet 



3. Green sandy clay 30 " 



2. Red clay 2 " 



I. Reddish clay 30 " 



Three miles north of the old town of Docum, in Dickens 

 County : 



5. White sandy clay 6 feet 



4. White diatomaceous earth 3 " 



3 . Purple clay 3 " 



2. White diatomaceous earth 4 " 



1. Reddish sandy clay 150 " 



These sections are valuable only in giving the approximate 

 thickness and general character of the deposits. No. i, of 

 both sections, is wrongly included in the Blanco series, as are 

 also Nos. 9, 10 and 11 of the section taken near Mount Blanco. 

 These strata belong probably to the Miocene age and are 

 apparently continuous with the beds they so much resemble 

 at Tule Canon and other portions of the Staked Plains. 



A complete section of this older formation is represented 

 by Cummins 's section taken "one fourth of a mile northwest 

 of H. C. Smith's ranch and one mile north of Mount Blanco": 



3 . Limestone 2 feet 



2. Stalactitic limestone 10 



I. Red clay (same as No. i of previous section) ^ . . . 30 



The diagrammatic section, Fig. 2, page 626, taken by the 

 writer across Blanco Canon and through the Blanco beds, 

 shows both of Cummins 's sections taken near Mount Blanco 

 and illustrates their relations to each other. 



It is thus seen that the Blanco beds, at Mount Blanco, like 

 the Rock Creek beds, apparently occupy a comparatively 

 narrow valley or basin formed for their deposition by ancient 

 erosion of the older beds. Like the Rock Creek beds also they 

 extend a long distance in one direction, being traceable south- 

 eastward for fifteen or twenty miles to the edge of the Plains. 

 Though the deposits differ in character from those of the Rock 

 Creek beds and the fauna indicates an earlier age, here, as at 

 Tule Canon, there is a total absence of any proof of a lake 

 origin for these beds and many evidences of river or stream 

 deposition. ^ 



i Cummins refers to the section taken near Mount Blanco and given above. 



