246 CHARLES KEYES 



geologists found a ready solution in the discovery that these 

 deposits were not accumulations of a single geologic age, but, in 

 their different parts, of three distinct ages. Beds of similar litho- 

 logic aspect of Pennsylvanian, Permian, and Triassic ages were 

 directly superposed, the normally intervening formations being 

 absent. This was, then, the real explanation why different inves- 

 tigators in different localities had determined such diverse dates 

 for their several sections. Even the unconformity planes were 

 overlooked. 



The recognition of "Red Beds" of Pennsylvanian age was a 

 distinct advance in the stratigraphy of the Southwest. 



It is a curious travesty on the fates that despite the acrimonious 

 controversy which waged for more than a full generation over the 

 possible presence of Permian beds in America, the one section 

 which would have most speedily ended it remained unnoticed, 

 albeit its fossils had long been fully made known. As early as i860 

 Shumard described what he distinctly designated a Permian fauna 

 from the Sierra Guadalupe on the New Mexico-Texas boundary; 

 but its true significance remained in complete obscurity for half a 

 century, when Girty accidentally pointed out its global relation- 

 ships. 



Although the Guadalupan succession of sandstones and lime- 

 stones is nearly 4,000 feet thick at the t3^ical locality the forma- 

 tion rapidly diminishes in force to the northward. Before the 

 Sandias are reached the Bernalillan "Red Beds" and the Cimar- 

 ronian "Red Beds" are brought together to form an uninterrupted 

 " Red B eds ' ' section . 



Cimarronian "Red Beds" clothe the backslope of the Guadalupe 

 Mountains and extend northeastward far into Kansas. There, 

 and through the Panhandle of Texas, they are in turn overlaid by 

 Triassic "Red Beds." The fact that a marked erosional uncon- 

 formity separates the two terranes is a recent observation. To the 

 northwest similar merging of "Red Beds" in continuous sequence 

 obtains; and the Triassic Doloresian formation immediately 

 succeeds Cimarronian deposits. 



In New Mexico the strata of Triassic age are predominantly 

 typical "Red Beds." There are two series of red shales and sand- 



