338 Correlation of the Upper Cretaceous Formations 



Both are characterized by the presence of a prolific Bryozoan fauna and 

 by the absence of Belranitella. The molluscan fauna is relatively meager 

 as well as absolutely so, and affords little direct basis for comparison. 

 Terebratula is rather abundant in both formations but none of the 

 species are identical. 



Correlation With India 



The correlation of the Upper Cretaceous deposits of the Middle Atlantic 

 states with India must of necessity be, for the most part, indirect, by the 

 way of the European beds, the route probably followed by the original 

 faunas, since the few species which are common are those occurring in 

 the European deposits as well, while the Indian element present in the 

 West Coast Upper Cretaceous faunas apparently did not penetrate into 

 the Western Interior. 



Three formations were definitely recognized by Stoliczka who mono 

 graphed the Indian fauna, the Ootatoor which he correlated with the 

 Cenomanian, the Trichinopoly which he considered as Lower Turonian, 

 and the Arrialoor, regarded as Upper Turonian in part and in part 

 Senonian. As Stoliczka suspected, these faunas are not homogeneous. It 

 is probable that thrfte horizons are represented in the Ootatoor, one below 

 the Cenomanian, one synchronous with it, and a third above it. The 

 lower horizon carries a number of cephalopods, including Mortoniceras 

 inflatum, which characterize the Albian. The second horizon carries 

 Acanthoceras rliotomagense and A. mantelli, the diagnostic ammonites 

 utilized by Stoliczka for correlating the Ootatoor with the Cenomanian. 

 The upper horizon of the Ootatoor contains Inoceramus labiatus, world- 

 wide in its distribution in the Turonian and genarally accepted as a trust- 

 worthy guide fossil of that period. In the Western Interior this species 

 has proved to be characteristic of the Benton and its absence from the over- 

 lying Niobrara is considered evidence of the post-Turonian age of the 

 latter. 



The fossil remains of the Trichinopoly as well as those of the Ootatoor 

 seem to represent three distinct life zones. Only the lower horizon con- 

 tains a fauna considered by the later European geologists as Turonian in 

 its affinities, chiefly because of the presence of a Baculite closely allied to 



