SUMMARY. 39 



A few fragmental remains of mosasaurs, crocodiles, and turtles have been found in the 

 zone, but all are too imperfect for specific determination. 



Too little is known concerning the vertical ranges of the vertebrate animals to render them 

 of value in exact correlation. 



PLANTS. 



With the exception of a few pieces of lignite or comminuted plant fragments, fossil plants 

 have been found at but one locality in the zone of Exogyra costata. A few imperfect leaf remains 

 were collected near the base of the zone on Cowikee Creek, a few hundred yards above its junction 

 with Chattahoochee River, in Barbour County, Ala. 



E. W. Berry, who collected and studied these specimens, in a letter to the writer says: 

 The fossil plants from Cowikee Greek are few in number and poorly preserved . The following forms are represented : 



Bauliinia sp. nov. 

 Platanus sp. nov. 

 Laurus sp . 



Salix sp. 



Sapindus sp. 



Fern, not determinable. 



The remains of the Bauhinia and Platanus are complete enough to demonstrate that they are new. The balance 

 are too poor for accurate determination, although they all appear to be distinct from any forms of the earlier eastern 

 Cretaceous floras. 



The slight evidence afforded by these plant remains seems to indicate that a change took 

 place in the Cretaceous flora of the region almost coincidently with the appearance of the fauna 

 characterizing the zone of Exogyra costata. 



SUMMARY. 



In eastern Alabama and in Georgia a terrane, previously regarded as forming the eastward 

 continuation of the Tuscaloosa formation of western Alabama, has been shown by its fossil plant 

 remains, on the authority of E. W. Berry, to be of Lower Cretaceous age and hence older than 

 the Tuscaloosa formation. The fossil plants furnishing the evidence for this determination of 

 age are too poor to permit exact correlation with better known floras elsewhere; but the presence 

 of large numbers of leaves, apparently dicotyledons, most of which are too poorly preserved to 

 permit accurate determination, seems to indicate that they are younger than the Patuxent 

 formation of the Potomac group (Virginia and Maryland) in which similar questionably identified 

 dicotyledons are but sparingly represented. 



The Tuscaloosa formation, the oldest of the Upper Cretaceous formations of the region, has 

 yielded no invertebrate fossil remains, but a large number of plant species have been obtained 

 from it. E. W. Berry, who is engaged in a study of the flora, correlates the basal portion of the 

 formation with the Raritan formation of New Jersey and the remainder of the formation with 

 the lower part of the Black Creek formation of the Carolinas (including the Middendorf arkose 

 member) and with the whole or at least a part of the Magothy formation of New Jersey. 



The Upper Cretaceous deposits above the Tuscaloosa formation are divisible on the basis of 

 their lithologic differences into formations and members. The physical relations of these units 

 to each other are such that it is not possible clearly to represent their age relationships by the 

 usual methods of mapping, for in many places the boundaries of lithologic units run obliquely 

 to the general strike of the beds and do not coincide with the boundaries of paleontologic zones 

 and subzones, and in several places important tongues of one unit project into the body of 

 another unit. On the basis of the distribution of the contained invertebrate fossils these deposits 

 have been divided into faunal zones and subzones whose positions are maintained along the 

 direction of the strike of the typical marine beds irrespective of lithologic variations. These 

 paleontologic parts furnish the means of correlating the deposits of the eastern Gulf region with 

 corresponding deposits in the Atlantic coast region. The relations of the paleontologic zones 

 and subzones to the lithologic units are graphically represented in Plates IX and X. 



The paleontologic parts recognized and their correlations are briefly summarized as follows: 



1. The basal beds of the Eutaw formation in the Chattahoochee region. These beds are 

 believed to be represented in the Carolinas by noninvertebrate-bearing beds making up the 



