STRATIGRAPHIC SUMMARY. 647 



SUBFORMATION. 



Early Palaeozoic. 



In the Rio Grande Valley of New Mexico, the Carbonic admits 

 of the following subdivision :*^ 



Manzano group. 



San Andreas limestone (500 ft). 



Yeso formation (1,000 ft.) (shale, limestone and gypsum). 

 Abo red sandstone (800 ft.) (fossiliferous). 

 {Hiatus and dis conformity.) 



Magdalena group. 



Madera limestone (500 ft.). 



Sandia formation (700 ft.) (limestones, shales and quart- 

 zitic sandstone). 



The Manzano group appears to be the equivalent of the Hueco 

 formation of Texas, and the Aubrey group of the Grand Canyon. 



In Colorado, the late Palaeozoics lie disconformably beneath the 

 Shinarump conglomerate (Triassic) and include in descending 

 order, the Moencopie beds (Permic), the Rico beds and the 

 Hermosa formation. In the San Juan district the Cutler red sand- 

 stone and shales of Permo-Carbonic age overlie the Rico and are 

 in turn succeeded after a mild unconformity by the Triassic 

 Dolores red beds. In the Grand Canyon section of Arizona, the 

 Aubrey and upper Red Wall approximately represent the Rico and 

 Hermosa. Both Aubrey and Rico are correlated with the Manzano 

 of New Mexico. 



In Arizona (Bisbee region) an apparently continuous series of 

 limestones forms the upper Palaeozoic — lying disconformably on the 

 Cambric (Abrigo limestone) and being unconformably succeeded 

 by the Comanchic Bisbee group. The series is Devonic at the 

 base (Martin limestone, 340 ft.) Mississippic farther up (Escabrosa 

 limestone, 700 ft.) and Carbonic in the upper part (Naco limestone, 

 3,000 ft.). The upper part of the Globe limestone of Arizona 

 (Globe Copper District) is also of upper Carbonic age, the lower 

 part being of upper Devonic age. 



In Utah, the Bingham quartzite series of upper Carbonic age 

 includes the following limestone members, in descending order: 



" Lee and Gordon, Bull. 389, U. S. G. S. 



