198 PHYSIOGRAPHY AXD GEOLOGY OF THE COASTAL PLAINT PROVIXCE. 



regarded as characteristically Cenomaniaii, although it may represent the 

 somewhat meager Turonian flora which succeeds it, and therefore belong 

 to that horizon. On the other hand, it is distinctly older than the Montana 

 flora of the West and its Senonian equivalent in Europe. 



"The evidence afforded, therefore, by the invertebrates and plants is 

 apparently in conflict, since the former present a Senonian facies throughout, 

 according to many invertebrate paleontologists, while the latter are regarded 

 by paleobotanists to be characteristically Cenomanian, or possibly Turonian, 

 in age. In this connection we find in the western Gulf that the Woodbine 

 formation, which is the representative of the Dakota sandstone farther Avest, 

 and which contains, as already pointed out, a Black Creek-Magothy-Tus- 

 caloosa flora, is succeeded by marine beds known as the Eagle Ford and 

 Austin Chalk formations which represent the Colorado group farther west, 

 and that these are again succeeded by deposits containing the Eipley fauna, 

 the latter being regarded as the equivalent of the Montana group of the 

 Rocky Mountain district. Since the Dakota has been generally regarded as 

 containing a Cenomanian flora and the Montana a Senonian fauna and flora, 

 the Colorado and its equivalents have been assigned to the Turonian. As 

 the Montana flora' is considered by paleobotanists as quite distinct from and 

 much younger in its facies than the Dakota, it is difficult to see, if we are 

 not to ignore the evidence of paleobotany, how, as some have supposed, the 

 entire series of Upper Cretaceous sediments on the Atlantic and Eastern 

 Gulf coasts can be assigned to the Senonian. Such a conclusion is still fur- 

 ther weakened by the fact that the Woodbine beds may be stratigraphicaily 

 continuous beneath the Mississippi embayment with the Tuscaloosa deposits 

 farther east in which the same flora occurs. A much more exhaustive study 

 of the stratigraphy of the Cretaceous deposits of the Central and Western 

 Gulf regions is clearly demanded, therefore, before these questions can be 

 finally settled. 



"It is apparent, in any event, that we are still forced to consider the pos- 

 sibility of the Upper Cretaceous sediments of the Atlantic and Eastern Gulf 

 coasts representing horizons earlier than the Senonian. Since the Turonian 

 has not been recognized by either a distinct fauna or flora in the series of 

 conformable strata under consideration, it is quite possible that a Cenoman- 

 ian flora, once established, continued its existence in America later than the 

 close of the Cenomanian epoch in Europe. At the same time it is conceiv- 

 able that the earlier elements of the invertebrate fauna are somewhat older 

 than paleozoologists have recognized, and that a greater or less portion of 

 the series under discussion must therefore be regarded as Turonian. The 



