332 Richardson — Stratigraphy of the upper Carboniferous 



and Pleurophorus off. subcostatus from seven miles north- 

 west of Roswell, New Mexico, and a Schizodus having the 

 general shape of S. harei, and a form suggesting by its shape a 

 small Myalina from the Rustler Hills, El Paso County, 

 Texas. Nevertheless the stratigraphy indicates that the red 

 beds of the Pecos Valley are to be correlated with part of the 

 Permian red beds of Oklahoma and northwest Texas, for they 

 were connected by tracing around the northern border of the 

 Staked Plains by W. F. Cummins in 1891 ; and on my map of 

 trans-Pecos Texas, published in 1904, the Castile gypsum and 

 Rustler limestone were referred to the Permian with a query. 

 Cummins' work has been confirmed by C. N. Gould, who has 

 mapped the Greer and Quartermaster formations, which are 

 part of the Permian red beds of Texas and Oklahoma, across 

 several counties in the panhandle of Texas, and along Cana- 

 dian River as far as the Texas-New Mexico boundary.* 



This stratigraphic correlation is in agreement with paleon- 

 tologic data recently obtained by Dr. J. W. Beede, with 

 whom 1 was associated in the field for a few days in 1909 and who 

 found fossils in a limestone in the red beds south of Lake- 

 wood, New Mexico, which he correlates with the "White- 

 horse-Quartermaster fauna. A discussion of this correlation, 

 however, is outside the scope of the present paper, and is left 

 to Dr. Beede. 



Section across east central New Mexico (No. 5, figs. 1 

 and 2). — In 1905 I traversed the line of the Eastern Railway of 

 New Mexico, then under construction, and made the following 

 observations between the Manzano Range and Pecos River. 



This region, considered as a whole, is an undulating plateau 

 125 miles wide. On the west the plateau is separated from 

 Rio Grande Yalley by the Manzano Range, and on the east 

 the escarpment of the Staked Plains rises above Pecos Yalley. 

 The western portion of the plateau, averaging about 6,000 

 feet in elevation, is dissected by the north-south trending 

 Estancia and Encino valleys and is surmounted by occasional 

 isolated mesas, while the eastern portion slopes gradually to an 

 elevation of 4,000 feet at Pecos River. The topography of 

 this belt is in marked contrast to that of the mountainous area 

 south of it in New Mexico and Texas, where other sections of 

 upper Carboniferous rocks described in this paper are exposed, 

 the difference in topography being largely due to the varying 

 hardness of the rocks. This contrast further emphasizes the 

 variability of the upper Carboniferous stratigraphy. 



* Gould, C. N., Geology and water resources of the eastern portion of the 

 Panhandle of Texas : Water Supply Paper U. S. Geol. Survey, No. 154, 

 1906 ; and Geology and water resources of the western portion of the Pan- 

 handle of Texas : Water Supply Paper U. S. Geol. Survey, No. 191, 1907. 



