454 PROCEEDINGS OF THE ACADEMY OF [1890. 



or lower series of the Texan Cretaceous/ but the position of these 

 beds in the true geological scale is not stated. Roeiner referred all 

 the Cretaceous deposits of the State of Texas to the Turonian and 

 Senonian of D'Orbigny, but Prof Hill, as the result of more recent 

 surveys, places the Comanche series in the Lower Cretaceous forma- 

 tion.^ This determination is, it appears to me, erroneous, and 

 is not borne out by the lists of fossils which are given by Prof. 

 Hill. The deposits may strictly be the Lower Cretaceous of 

 America, but they are not the correspondents of what is recognized 

 as the Lower Cretaceous of geologists generally, inasmuch as they 

 represent a horizon at least as high up in the series as the 

 Cenomanian (not Neocomiau, as stated by Hill). It isonly necessary 

 to name a few of the species indicated by Prof Hill as occurring in 

 the formation to be convinced of the true (comparatively high) posi- 

 tion of the horizon : Exogyra Matheroniana, Ostrea carinata, Peeten 

 cequicostatus, Peden quadricostatus (?), Protocardia Hillamim, etc., 

 all well-known European forms, and mostly distinctive of the 

 Cenomanian horizon. In addition to these forms Janira Fleuri- 

 awsmnrt, of D'Orbigny, also a Cenomanian form, is enumerated in 

 one of the lists.^ Prof. Hill refers to a species of Crioceras {Ancylo- 

 ceras) as indicating the Neocomian horizon, but the form in question 

 has been identified by Prof. Hyatt with Lituites Bkkvioreanus, from 

 the Niagara (Silurian) limestone of Indiana ; * nor is the generaliza- 

 tion correct that the presence of Rudistes, Nerinreas, Pleurotomarias, 

 and Globiconchas " while not decisive, is corroborative of the low 

 position of the Comanche series." * If the word " high " were sub- 

 stituted for "low " the generalization would have been more nearly 

 correct. It is stated that " it was chiefly upon the evidence of the 

 Exogyra Texana and the Ostrea carinata that Roemer made this 

 Comanche series belong to the Upper Chalk of Europe." This is 

 hardly the fact. Roemer rightly emphasizes the presence in the for- 

 mation of Cardium. HiUanum and Peden quadricostatus — European 

 Upper Cretaceous species — and of the following analogues of the 

 Upper Cretaceous species : Adceonella dolium (representing^. Icevis), 



1 Pioc. Acad. Nat. Sciences, Phila. 1887, p. 43. 



2 Check List Cret. Inv. Foss, Texas, 1889; Am. Jouin. Science, 1887, pp. 

 303-307. 



3 Am. Journ. Science, 1887, part 2, p. 303. 



4 Hill, Check List, p. 21. 



5 Am. Jouni. Science, 1887, part. 2, p. 307. 



