BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 2, pp. 503-528 May 5, 1891 



THE COMANCHE SERIES OF THE TEXAS-ARKANSAS 



REGION. 



BY ROBERT T. HILL. 



{Read before the Society December 30, 1890.) 



CONTENTS. 



Page. 



Introductory Statement 503 



Definition of the Terranes 504 



Constitution of the Comanche Series 504 



The Trinity or Basal Division 505 



Separation 505 



The Trinity Sands 505 



The Glen Rose Beds '. 507 



The Fredericksburg or Comanche Peak Division 509 



General Composition 509 



The Paiuxy Sands 510 



The Gryphcea Rock and Walnut Clays 512 



The Comanche Peak Chalk 512 



The Caprina Limestone 513 



The Goodland Limestone 514 



The Washita or Indian Territory Division 515 



General Aspect 515 



The Kiamitia Clays or Schloenbachia Beds 515 



The Duck Creek Chalk 516 



The Fort Worth Limestone 516 



The Denison Beds 517 



Variation in Character of the Deposits 518 



Subsidence recorded in the Comanche Series 518 



Stratigraphic Value of the Terranes 519 



Topographic Expression of the Comanche Terranes 520 



The Age of the Comanche Series 523 



Discussion ; 525 



Introductory Statement. 



The Comanche series of rocks has been partially described by the writer 

 and others in several previous papers. They represent in time the marine 

 sedimentation between the lacustral land epoch of Perrao-Triassic red beds 

 and the upper Cretaceous subsidence beguu in the Dakota epoch. Without 



LXXIV-BuLL. Geol. Soc. Am., Vol. 2, 1890. (503) 



