280 Annals of the Carnegie Museum. 



part of the State it lies on the Wellington formation, and in the south 

 and southwestern parts on the Cimarron formation, with Kiowa and 

 Cheyenne of the Lower Cretaceous intervening at certain places. 

 See N. H. Darton, United States Geological Survey, Professional 

 Paper No. 32, 1905, from which also the table given on p. 282 is taken, 

 giving the geological formations in central and western Kansas. 



Correlation of the Dakota Formation. 



There is still some uncertainty as to the exact correlation of the 

 flora of the Dakota Formation with other Cretaceous formations of 

 America; still greater is the uncertainty of its correlation with the 

 floras of the Old World. 



One of the strongest evidences of the correlation of different for- 

 mations is derived from the animal remains found in the rocks. Un- 

 fortunately very few animal fossils have been found in the Dakota 

 Formation. Stanton, in his " Succession and Distribution of Later 

 Mesozoic Invertebrate Faunas in North America" ("Outlines of Geo- 

 logic History " by Willis and Salisbury, 1910), says: " The invertebrate 

 fauna of the Dakota sandstone is too meager to be of much value. It 

 consists of a few brackish-water species with Unio and a few other 

 fresh-water shells in other strata and at the top some marine species, 

 that probably really belong with the succeeding Colorado fauna." 



In our study of this collection of plants we have discovered no 

 facts, which add anything new to our knowledge of the correlation of 

 the Dakota with other Cretaceous formations. The following, there- 

 fore, is merely a summary of the opinions given by those who have 

 made careful comparisons of the Dakota Formation with other for- 

 mations of the Cretaceous period. 



In discussing the flora of the Raritan Formation. Berry (Geological 

 Survey of New Jersey, Bulletin 3, 191 1, pp. 20-22) incidently men- 

 tions the correlation of the " Dakota Formation " in the following 

 manner : " European paleontology furnished abundant and well-char- 

 acterized Cenomanian and Senonian floras for comparison, and by 

 this standard the Raritan, as well as the somewhat younger Dakota 

 and Magothy floras, are clearly Cenomanian floras." He further says 

 that the Woodbine, Tuscaloosa, Eutaw, Middendorf, Bladen, and 

 Magothy floras are southern and eastern representatives of the Da- 

 kota Group. 



