OKLAHOMA ACADEMY OF SCIENCE 89 



at the tcp of the formation. The Caddo formation consists of alter- 

 nating beds of limestone and shale. It is the most abundantly 

 fossiliferous formation in the area. The Bokchito formation, which 

 overlies the Caddo formation, consists chiefly of shale with a few 

 beds of brown sandstone and shell becU which have been replaced by 

 iron. The yoimeest Comanchean formation in Love county is 

 the Bennington limestone. It is a bluish brown hard massive lime- 

 stone containing an abundance of a peculiar pelecypod {Exogyra 

 arietina Roemer). 



The lov/est definable fossil horizon in the Comanchean of 

 Love county occurs in the basal bed (Walnut Clay equivalent) of 

 the Goodiand limestone. It is marked by an abundance of fossils, 

 particularly a rather small easily recognizable echinoid, Enallaster 

 texanus Roemer. This species, so far as is known, does not occur 

 abundantly at any other horizon in the section. Other fossils occur- 

 ring in abundance at this horizon include ; Exogyra texana Roemer, 

 Prutocardia texana Conrad and Cyprimeria texana Roemer. 



The top of the Goodiand limestone contains a pecularily marked 

 ammonite, Schhenbachia acutocarinata Shumard. This ammonite 

 is limited in vertical distribution occuring only in the upper few 

 feet of the Goodiand lim.estone, a few scattered individuals ranging 

 into the basal part of the Kiamichi formation. 



The top of the Kiamichi formation is marked by a hard shell 

 conglomerate varying from one to two feet in thickness. This shell 

 conglomerate is composed almost entirely of Gryphea navia Hall. 

 This species also occurs rather abundantly in the clay underlying 

 the shell conglomerate. An ammonite, Schloenhachia belknapi Mar- 

 cou, very similar to Schloenhachia acutocarinata Shumard occurs 

 in the upper part of the Kiamichi formation, a few forms ranging 

 into the basal part of the Caddo formation. 



The lower part of the Caddo formation, that is the lower 22 

 feet constitute the next horizon. Throughout this horizon there is 

 an abundance of Inoceramus ccmancheaniis Cragin. They do not 

 occur abundantly at any other horizon in the section. The extreme- 

 ly large ammonite, Desmoceras brasoense Shumard dominates the 

 lower part of the Caddo formation. Although limited to the upper 

 part of this horizon, they occur in such abundance and are so large 

 that they are by far the most prominent fossil in the entire Coman- 

 chean section. Other ammonites found in the lower part of the 

 Caddo formation include; Schhenbachia trinodosa Boese and Ham- 

 ites comanchensis Adkins & Winton. An abundant horizon of Hein- 

 iaster whiici Clark occurs immediately above the Desr.ioceras braz- 

 oense Shumard horizon in the lower part of the Caddo formation. 



