Caprina Limestone Beds. 103 



serious doubts as to the true generic position of the forms. It 

 can now be said that, with the single exception of Radiolites 

 auslinensis, all of these forms in Texas come from the Caprina 

 limestone. The following is a list of the forms thus far described : 



CHAMID.E. 

 Diceras (?) Roemer. 



Requienia bicornis Meek, 1876. Fort Lancaster, Texas. 

 patagiata White, 1884. Near Austin, Texas. 

 " texana Roem., 1852 ; White, 1884. Near Austin, Texas. 

 Highlands between New Braunfels and Fredericks- 

 burg. Marcou, 1858, reports this form at " Comet 

 creek, on left bank of the False Washita." 

 Monopleura marcida White, 1884. Near Austin, Texas. 



" subtriquetra Roem., 1852. Valley of San Saba and 



upper arm of Pedernales river. 

 pingiuscula White, 1884. Near Austin, Texas. 

 texana Roem., 1852. 



Idithyosarcolithes anguis Roem., 1888, Barton creek, west of Austin. 

 (?) (Caprina) crassiftbra Roem., 1849, 1852. 

 (?) (Caprina) guadalupae Roem., 1849, 1852. 

 (?) (Caprina) planata Con., 1855. Oak creek, 



near Pecos, Texas. 

 (?) (Caprina) occidental Con., 1855, 1857. Pecos 



river near mouth. (A. Schott.) 

 (?) (Caprina) texana Roem., 1849. 

 Plagioptychus (?) cordatus Roem., 1888. 



Radiolites (Hippurites) texanus Roem., 1849, 1852. 

 davidsoni sp. nov. 



All of the above species occur in the Caprina limestone. 

 Radiolites austinensis Roemer, is the only other form from the 

 Texas Cretaceous. It occurs in the Austin chalk, and is so 

 radically different in every aspect that it hardly belongs in the 

 same group with the lower forms. With the exception of Mo- 

 nopleura and Requienia, which range downward into the Trinity 

 Division, all the other genera occur only in the Caprina lime- 

 stone, appearing suddenly upon the scene with these beds and 

 completely vanishing thereafter. 



Radiolites texanus Roemer, which comes from the Caprina 



