XL 



INTRODUCTORY REMARKS. 



Alabama section, from facts communicated by Prof. A. Winchell— Continued. 



From this .section it will be seen that there is at the base of the Ala- 

 bama Cretaceous series, as well as in Mississippi, a considerable thickness of 

 shale or clay, sand, etc., containing, in the former State, dicotyledonous leaves, 

 and apparently corresponding to the Dakota group, or No. 1 of the Upper 

 Missouri section; while above, there comes a great series of sand, clays, 

 soft whitish limestone, etc., containing a group of fossils showing that we 

 have here a representation of perhaps both the Fort Pierre and Fox Hills 

 groups (Nos. 4 and 5) of the Upper Missouri section. As in Mississippi, 

 we have no satisfactory evidence, however, that either the Fort Benton or the 

 Niobrara group is represented in the Alabama section. 



In the same paper, of May, 1857, from which the foregoing Alabama 

 section is cited, we also gave (page 127) for comparison, a section of the 

 New Jersey Cretaceous rocks, compiled from the Geological Reports of Pro- 

 fessor Ketchel and Professor Cook, showing the parallelism of the Cretaceous 

 subdivisions there with those of the Upper Missouri, as follows: 



'Now known as Plaeeniiceras placenta. 



t This has since been found to be a worn specimen of the old gouus Ammononites. 



