18 Hill Paleontology of the Trinity Division. 



fessors Ward and Fontaine, originally in the Potomac region,* 

 were long since referred by them to the Wealden', before they 

 were known to occur in the magnificent Texas stratigraphic 

 series. 



The vertebrates have never been systematically studied nor 

 collected, but the genera found all occur in the Lower Creta- 

 ceous of Europe. 



Of the invertebrates the ostracoid crustacean Cypridea of the 

 Glen Rose lower beds is. in Europe as in Texas, a prominent 

 feature of the Wealden (Lower Neocomian) beds. 



The foraminifer Patellina (Orbitiilitcs) texana Roemer is indis- 

 tinguishable from the Orbitulites, which characterizes the Upper 

 Neocomian of France, and occurs there under lithologic condi- 

 tions similar to those in Texas. 



Of the Pelecypod mollusca proper the Anomia is indistinguish- 

 able from the Anomias of other ages. 



The only Ostrea (0. franklini Coquand) seem identical with 

 the figures of a form which has been described under many spe- 

 cific names from the Upper Jurassic, and Lower Cretaceous of 

 Europe. 



Pecten stantoni belongs to a group of the PectinidsR^ which has 

 great specific development in the Neocomian of France. Spain, 

 and Portugal. 



Modiola, Leda, CuculLxa, Protocardia, Corbicula, Pholadomya, 

 and the doubtful form called Isocardia have a wide range in the 

 geologic column, but the forms found in the Trinity Division 

 have a general varietal resemblance to those of the Neocomian. 



The only well-defined species of Triyonia (T. stolleyi sp. nov.) 

 belongs to the scabrate forms peculiar to the Cretaceous and 

 later epochs. This is an important fact against the possible 

 Jurassic age of the beds. 



The aberrant genera, Requienia and Afonopleura, which abound 

 in the Glen Rose beds," are both characteristic Lower Cretaceous 

 genera, occurring abundantly in Europe in the Neocomian beds 

 and not ranging higher than the Cenornanian. . In describing 

 Requienia (Caprotina) texana. Roemer asserted that it was hardly 

 distinguishable from the characteristic Caprotina lonsdallli of the 

 Neocomian of France. A 



Of the Gastropoda, the genus Vycarla is represented by V. 

 branneri resembling a peculiar species of the European Neo- 



*See various papers by Professors Lester F. Ward and W. M. Fontaine 

 on the Potomac flora of the North Atlantic coast. 



