584 TIMOTHY WILLIAM STANTON 
areas in Texas and Indian territory. Marcou has maintained the 
correctness of his determination in numerous subsequent papers, 
but for various reasons his opinion, though essentially correct, 
did not meet with general acceptance for many years. The 
principal causes that conspired to prolong this misconception 
were (1) Marcou’s own error in referring to the Jurassic certain 
New Mexican exposures of a part of the same series; (2) 
Roemer’s previously published important work, ‘Die Kriede- 
bildungen von Texas,” in which on paleontological grounds all the 
Texan Cretaceous beds were referred to the Upper Cretaceous ;* 
(3) the publication of Shumard’s? section in which the strati- 
graphic succession is very erroneously given, and (4) the fact 
that the investigation of other regions in the United States did 
not reveal any Lower Cretaceous beds that were really compara- 
ble with those of Texas. The subject remained thus until 1887 
when the publication of papers by Dr. C. A. White3 and Mr. R. 
T. Hill,4 based on the latter’s field work, established the fact that 
there is in Texas a great series of Cretaceous rocks underlying 
the generally recognized Upper Cretaceous of other parts of the 
country. This is the Comanche series that has since become so 
familiar through the numerous papers of Mr. Hill. 
« The idea has been current for some years that ROEMER’S principal error was a 
stratigraphic one in placing his “‘ Cretaceous of the Highlands” above the “‘ Cretaceous 
at the foot of the Highlands” as he did tentatively in his earlier work ‘“‘ Texas,” but a 
careful perusal of the introductory pages—especially page 19——of the “ Kreibil- 
dungen” will show that he did not finally attempt to establish any stratigraphic 
succession, and that he admitted that there were both paleoritologic and physical 
reasons for regarding the beds of the Highlands as older than the others, and he 
suggested that their topographically higher position might have been caused by a 
fault. His real error was that in his paleontological comparisons with the Cretaceous 
of southern Europe, he did not recognize the now well-known fact that there are two 
distinct horizons, one in the Upper Cretaceous and the other in the Lower, each char- 
acterized by peculiar species of Rudistae, Chamidae, etc. 
2Trans. Acad. Sci., St. Louis, Vol. I; pp. 582-589, 1856-1860. 
3On the Cretaceous formations of Texas and their relations to those of other parts. 
of North America. Proc. Phila. Acad. Nat. Sei., 1887, pp. 39-47. 
4The topography and geology of the Cross Timbers and surrounding regions in 
northern Texas. Am. Jour. Sci., 3d ser., Vol. XXXIII, pp. 291-303, pl. 6. The 
Texas section of the American Cretaceous. Am. Jour. Sci., 3d ser., Vol. XXXIV; 
1887, pp. 287-319. 
