Permo-Carboniferous Ammonoids of the Glass Mountains 27 



lent of the Wichita formation of northern central Texas. It belongs 

 possibly to the Clear Fork division, but no details are known. 



Below the Clear Fork division we find in northern Texas the Wichita 

 formation composed of red, bluish and gray-white sandstones, red con- 

 cretionary clays, occasional blue shales and clay-ball conglomerates. 

 Further south these beds are supposed to be represented by the blue- 

 black and gray shales and clays and the hard compact and thick-bedded 

 limestone of the Albany formation. This member of the Central Texas 

 series thus would correspond to the lower part of our Leonard forma- 

 tion, the Hess formation, the unknown strata destroyed by the Permo- 

 carboniferous erosion, and the Wolfcamp formation. The invertebrate 

 fauna of the lower Wichita-Albany has never been described and the 

 ammonoids are not known. No nearer comparisons can be made with 

 other Permian localities of North America. In the Appalachian region 

 the Permian consists of plant-bearing beds of lower Permian charac- 

 ter, while in Nova Scotia this series probably corresponds to higher 

 beds of the Permian (Saxonian and Franconian). Unfortunately, no 

 detailed studies about the Permian in the Basin Ranges and the Rocky 

 Mountains are available, although the Permian seems to be well re- 

 presented there. The fossils found by Freeh near Fort Douglas near 

 the Great Salt Lake seem to represent principally an upper Permian 

 fauna. Very little is known about the shales which represent the Per- 

 mian in California;. especially in the southern part of the Sierra Neva- 

 da, they seem to be entirely sterile. 



Very little can be said about the interesting locality discovered by 

 Haarmann^ at Las Delicias near Torreon, Coahuila, in northern Mex- 

 ico. The small fauna which has been described by W. Haack^ belongs 

 undoubtedly to the upper Anthracolitic and may very well represent 

 one of our Permo-Carboniferous zones, but it is impossible to make 

 a more exact determination of its age. 



Still less is known about the upper Anthracolitic existing in Chiapas, 

 southern Mexico, Guatemala and British Honduras, although a list 

 of the fossils from the last two countries has been made by E. StoUey 

 and pubUshed by Carl Sapper. 



^Haarmann, Coahuila. 



^Haack, Permfa/una a. Nordmexico. 



