THE WICHITA FORMATION OF NORTHERN TEXAS 1 



C. H. GORDON 



University of Tennessee, Knoxville, Tenn. 



With discussions of the Fauna and Flora by 

 GEORGE H. GIRTY and DAVID WHITE 



INTRODUCTION 



The geology of the "Red Beds" area of northern Texas has 

 long been recognized as one of the perplexing problems of North 

 American geology. The interest aroused by the discovery in these 

 beds of a fauna which was regarded by Cope, C. A. White, and 

 others as Permian has brought forth a number of papers bearing 

 on this region, most of which are based on transient visits in search 

 of fossils, generally with scant attention to the detail of stratig- 

 raphy. 



This paper is based upon investigations made in connection 

 with the study of underground water conditions for the United 

 States Geological Survey during the field seasons of 1906 and 1907. 

 The collections of invertebrate fossils made in the course of the 

 investigations were submitted to Dr. George H. Girty of the Survey, 

 who also had for study additional materials collected by E. O. 

 Ulrich in former years. 



STRATIGRAPHY OF THE REGION 



The u Red Beds" area. — The area occupied by the "Red Beds" in 

 northwestern Texas is bounded on the west by the eastern escarp- 

 ment of the Llano Estacado, and extends eastward along the Red 

 River to Montague County, where the formations pass from sight 

 beneath the basal beds of the Cretaceous. From this point the 

 eastern boundary of the "Red Beds" bears south and then west- 

 ward, following approximately the lines between Jack and Clay, 

 and Young and Archer counties as far west as the Salt Fork of 

 the Brazos. From this point it bears southwestward to the south- 



1 Published by permission of the Director of the United States Geological Survey. 



