34 Hill Paleontology of the Trinity Division. 



Dr. Roemer described this large and abundant species of the 

 Glen Rose beds from specimens collected on the Pedernalis 

 river. He also described Natlca (Tylostoma) pr-egrandis, which 

 he asserted differed only by its larger size. 



The species occurs in the greatest abundance throughout the 

 extent of the Glen Rose beds in Arkansas, Texas, and Mexico, 

 and is preserved only as casts, without shell structure. From 

 observations of hundreds of individuals, I am of the opinion that 

 the two species of Roemer are identical. 



These forms are indistinguishable from many species described 

 from the Neocornian of France and Spain, where the genus T\j- 

 lostoma has its culmination, ranging, according to Zittel, from the 

 Upper Jurassic. Tyiostoma similimum Choffat, from Portugal, a 

 characteristic Neocomian form, is quite closely related, if not 

 identical with the Texas species. It also resembles N. yigas 

 Bonn, of the Jurassac. 



The specimen figured here is a large flattened individual, 

 illustrated in order to show the size and variation in comparison 

 with the typical forms figured by Roemer. 



This form occurs throughout the Neocomian of Mexico, in 

 Venezuela, Bogota, and on the central Pacific coast of Soutli 

 America, and is one of the distinguishing fossils of the Glen Rose 

 beds. 



Vicarya branneri sp. nov. 

 Plate V, Figs. 1-7. 



Plcurocera strombiformis (Schlotheim) Hill. Neozoic Geology 

 of Southwest Arkansas, p. 129, plate ii, figs. 1, 2, 3, 4, 5, (>, 7, 

 7a, 76, 8, 9, 10, 11, 12, 12a; plate iii; figs. G, Or/,, 66, (k, copies of 

 European figures. 



Compare 



Vicarya helvetica Vcrneuil and De Loriere. Description des 

 Fossilcs (In Neocomien Superieur de Utrillas et ses Environs, p. 

 L', plate i. fig. 1. 



Vicarya lujani Verneuil and De Loriere. Ibid., p. 5, plate i, 

 fig. 3. ' 



Vicarya strombiformis Verneuil and De Loriere. Ibid., p. 7, 

 plate i, fig. 4. 



Vicarya pradoi Verneuil and De Loriere. Ibid., p. 10, plate i, 

 fig. 5. 



