90 THE UNIVERSITY OF OKLAHOMA 



The middle member of the Cadd^o formation, which consists 

 of ahont CO feet of clay shale does not contains any fossils in 

 abundance. It is, in fact, rather noticeab.e because of the absence 

 of fossils. 



The upper pr^rt of the Caddo formation, including about 75 

 feet of alternating beds of limestone and shale immediately overly- 

 ing the clay shale member constitutes the next horizon. Tt is char- 

 acterized by a great num.ber of forms rather than the marked 

 abundance of any single species. Two important and easily recog- 

 nizable echinoids occur in this horizon, namely Holaster simplex' 

 Shumard and Hemiaster clegans Shumard. The well known am- 

 monite Schloenbachia leonensis Conrad also occurs at this horizon. 

 A rather abundant Pecten horizon was found near the top of the 

 Caddo formation. A few scattered individuals of Ostrea carinata 

 Lamarck were also found near the top of the Caddo formation. 

 The uppermost beds of the Caddo formation also contain, in con- 

 siderable abundance, Exogyra americana Marcou. Large fucoids 

 occur abundant''y throughout the Caddo formation, but so far as 

 known are limited to this formation. 



The Bokchito formation, which consists principally of clay 

 shale and sandstone with occasional shell beds is not very fossilifer- 

 ous except locally. Several of the she'l beds have been replaced by 

 iron, but the fossils in many cases are not well preserved. The 

 most prominent of these shell beds is found near the top of the 

 formation and consists principally of Protocardia texana Conrad, 

 with numerous other fossils in lesser abundance. 



The Bennington limestone is characterized by an abundance of 

 Exogyra arietina Roemer. It also contains a few Ostrea quadripli- 

 cata Shumard and a few echinoids. 



Two specimens of a brachiopod (Terrabratula wacoensis Roe- 

 mer) were found in the Comanchean section of Love county, one in 

 the lower part of the Caddo formation immediately overlying the 

 Desnioceras brasoetise Shumard horizon and the other in the Ben- 

 nington limestone. 



A generalized summary of the facts and their significance. 



Enallastcr texanns in abundance denotes lower Goodland lime- 

 stone. 



Schloenbachia acutocarinata indicates upper Goodland limestone. 



Gryphea navia is characteristic of the Kiamichi formation. 



The following fossils indicate Lower Caddo : Inoceramus co- 

 mancheamis, Hamites comanchensis, Schloenbachia trinodosa, Des- 

 moceras brazoense, Hemiaster whitei. 



The following fossils indicate Upper Caddo ; Hemiaster elegans. 



