Emery — Green River Desert Section, Utah. 563 



Section of Chinle formation in The Ledge along trail from 

 French Spring to Elaterite Spring. 



1. Sandstone, red-brown, massive, cross-bedded — Win- 



gate sandstone. 



2. Shale, very sandy, becoming increasingly so toward 



top ; red-brown in color ; grades into overlying 

 Wingate sandstone 150' 



3. Shale, hard, friable, variegated lavender, heliotrope, 



mauve, blue, white and cream 115' 



4. Shale, sandy, greenish, coarse, with dark limestone 



conglomerate at top 35' 



5. Conglomerate and coarse sandstone, Shinarnmp 



conglomerate. 



300' 

 The Chinle is litliologically strongly in contrast with 

 the underlying Shinarump conglomerate, which is sig- 

 nificant, and which may indicate an unconformity though 

 this does not necessarily follow. At the top of the Chinle 

 along The Ledge there is no evidence of unconformity, 

 for the Chinle seems to grade insensibly into the massive 

 Wingate sandstone above. On the other hand, near Tem- 

 ple Mountain there is a marked lithologic difference in 

 the Chinle and La Plata which may perhaps indicate a 

 time break. In the Navajo country east of Carrizo 

 Mountain in extreme northeastern Arizona I found evi- 

 dence of such a break bet wen the Chinle and overlying 

 Wingate sandstone, and Gregory obtained evidence of 

 unconformity at this horizon at several other places in 

 the -Navajo country. 12 Thus it appears likely that the 

 Chinle may be unconformably limited at the top and 

 bottom. 



That the beds described above are to be correlated 

 with the Chinle formation on the Navajo Reservation I 

 think there is no reason to doubt. The peculiar lithologic 

 characters of the Chinle in the Reservation, including 

 the presence of limestone conglomerate, are duplicated in 

 Green River Desert, and this together with its position 

 between such prominent and unmistakable key-beds as 

 the Shinarump below and the massive Wingate sandstone 

 above, makes the correlation of the formations in the two 

 localities imperative. The Chinle is identical with the 

 beds referred by Gilbert to the (c) or upper division of 

 his Shinarump group in the Henry Mountains region. 13 

 It is Triassic in age. 



12 Gregory, H. E., op. eit., p. 48. 



13 Gilbert, G. K., op. eit., p. 6, stratigraphic section. 



