stanton.] OTHER AMERICAN CRETACEOUS FAUNAS. 49 



Associated with these is a large number of other species that have 

 not been recognized in our area. The fauna of the Austin limestone 

 seems to be somewhat more closely related to that of the overlying 

 beds than is the Colorado fauna to the Montana. 



Some of the species doubtfully assigned to the Eagle Ford shales are 

 also listed as occurring in the Denison beds at the top of the Comanche 

 series, but this is probably an error, since the species in question are 

 entirely Upper Cretaceous forms and several of them occur in the Colo- 

 rado formation. 



Beneath the Eagle Ford shales the Timber Creek formation (Lower 

 Cross Timber sands of Hill) contains an unstudied marine fauna that will 

 probably prove to be closely related to the Colorado fauna, especially to 

 that part of it that occurs in the lower portion of the formation in Utah. 1 



The Upper Cretaceous faunas of Mexico have not been studied, but 

 the occurrence of Inoceramus labiatus at several localities in Chihuahua 

 indicates the presence of the Colorado fauna there*, though Dr. White 

 has suggested that the Upper Cretaceous strata of that region are not 

 divisible into distinct formations. 



The Colorado fauna has not been recognized in any of the states east 

 of the Mississippi. If it is represented at all in the Alabama-Missis- 

 sippi region it should be sought in the Tombigbee sands and the Eutaw 

 formation and perhaps the lower part of the " Eotten Limestone," none 

 of which has been much studied paleontologically. 



On the Pacific coast of the United States the Cretaceous faunas gen- 

 erally are very different from those occurring east of the mountains, 

 having few if any species in common. None of the characteristic Colo- 

 rado species has been found there, and it has not yet been determined 

 whether any of the Cretaceous formations of California, Oregon, and 

 Washington are strictly the equivalents of the Colorado formation. Far- 

 ther north, however, in the upper shales and sandstones of the Queen 

 Charlotte islands Inoceramus labiatus is reported 2 to occur, and this may 

 be considered the most characteristic species of the Colorado fauna. 



In the Rocky mountain region of British America, Dr. G. M. Daw- 

 son 3 obtained the following species that clearly belong to our fauna: 



Ostrea congesta. Pholadomya papyracea. 



Inoceramus exogyroides. Scaphites warreni. 



I. undabundus. S. vermiformis ? 

 I. labiatus. 



From the " Niobrara-Benton formation " in the Duck and Eiding 

 mountain district of Manitoba, Mr. Whiteaves 4 records the following 

 species : 



Serpula semicoalita. Inoceramus labiatus. 



Lingula subspatulata? Modiola tenuisculpta. 



Ostrea congesta. Belemnitella manitobensis. 



Anomia obliqua. Loricula canadensis. 



J Vide White, C. A., Bull. 82, U. S. Geol. Sur., p. 121. 2 Whiteaves, J. F. : Mesozoic fossils, Vol. 1, p. 193. 

 * Whiteaves, Cont. to Can. Palaeout, Vol. I, pp. 83-86, « Ibid., pp. 185-191. 



Bull. 106 4 



