NO. 4 PHYSIOGRAPHY OF ROCKY MOUNTAINS LEE 23 



The Toclilto is represented in western New Mexico by a thin lime- 

 stone which is described as appearing- " singularly out of place " 

 between two massive sandstones. 



Farther to the east this limestone is recognized as the peculiar 

 bituminous shaly limestone which underlies the gypsum of the 

 El Rito section, with typical Wingate sandstone below it and another 

 sandstone above. 



Still farther east, near Jemez, N. Mex., 1 the limestone and gypsum 

 appear above the Wingate, but no equivalent of the Navajo is found 

 unless it is included in the lower part of the beds here classed as 

 McElmo. However, near Cerrillos, south of Santa Fe, and also in 

 the Sandia Mountains, east of Albuquerque, the gypsum, limestone, 

 and Wingate sandstone are typically developed, according to Darton, 

 and between the gypsum and the overlying variegated beds are rocks 

 composed chiefly of pink and yellow sandstone which may represent 

 upper La Plata. These beds east of the Rio Grande are separated 

 from those farther to the west by a covering of younger rocks, and 

 the correlations must be made chiefly on lithologic similarity of beds 

 and on sequence of formations. 



About 25 miles east of the point where the Cerrillos section was 

 measured, and a few miles south of Lamy, N. Mex., a sandstone 

 between typical " Red Beds " and typical Morrison (pi. 2, fig. 1) is 

 regarded as Wingate by Darton, although no gypsum has been found 

 above it. However, still farther to the east, near Las Vegas, N. Mex., 

 the sandstone which holds the same relative position has a thin lime- 

 stone above it, which is described as being the same as that which caps 

 the Wingate sandstone of localities farther to the west. This lime- 

 stone separates the sandstone from the Morrison and there seems to 

 be no room here for an equivalent of the upper La Plata sandstone. 

 Darton regards the sandstone as equivalent to the Wingate, although 

 in the Santa Fe guidebook " it is labeled Triassic ( ?). On the other 

 hand, I became convinced some years ago, while working in that part 

 of the country, that this sandstone is the same as the Exeter sandstone 

 (pi. 3, fig. 1) of northeastern New Mexico which I then referred 

 with the query to the Triassic. 3 Like the W T ingate, this sandstone is 

 overlain at its type locality by limestone and gypsum, but unlike the 

 Wingate it is variable in thickness and is entirely absent in some 



1 Darton, N. H., Manuscript in preparation. 



2 Darton, N. H., U. S. Geol. Survey Bull. 613, fig. 13, 1915. 



3 Lee, W. T., U. S. Geol. Survey Bull. 389, IQ09- 



