Maryland Geological Survey 223 



derives its importance from the fact that the Cheyenne sandstone is over- 

 lain by the marine Kiowa shales containing a Washita fauna, thus invali- 

 dating the proposal of the term Comanchean as a substitute for Lower 

 Cretaceous. 



Overlying the Kiowa shales are a series of intercalated sandstones and 

 clays, the latter sometimes carrying leaves and the whole from 135 feet 

 to 445 feet in thickness. Then comes the typical leaf-bearing Dakota 

 sandstone which represents the littoral deposits of the advancing Benton 

 sea and which forms a widespread deposit extending from northeastern 

 Texas (Woodbine formation) northward to Minnesota and westward 

 beyond the present site of the Rocky Mountains. It is represented 

 in the Canadian provinces by the Mill Creek series of Dawson. 



The Dakota Sandstone 



The flora of the Dakota sandstone was first studied by Ileer and the 

 literature is too extensive for citation here. The chief contributions 

 were made by Lesquereux, and little has been added since his final mono- 

 graph was published in 1892. 1 North of the International Boundary the 

 Dakota group flora was recognized by Dawson in the Mill Creek series 

 of Canada. 



Combining all of the published work dealing with areas within the 



United States, that for the Dominion of Canada being given in another 



place, results in the following lists of species : 



Abietites ernestinm Lesquereux 

 Acerites multiformis Lesquereux 

 Acerites pristinus Newberry 

 Alnites crassus Lesquereux 

 Alnites grandijolia Newberry 

 Ampelophyllum attenuatum Lesquereux 

 Ampelopliyllum firmum Lesquereux 

 Ampelophyllum ovatum Lesquereux 

 Andromeda acuminata Lesquereux 

 Andromeda cretacea Lesquereux 

 Andromeda parlatorii Heer 



1 Lesquereux, L., The Flora of the Dakota Group. Mon. U. S. Geol. Survey, 

 vol. xvii, 1891. 



