148 PROCEEDINGS OF THE PALEONTOLOGICAL SOCIETY 



the Bridger Basin and preserved in the Marsh collection at Yale. While mak- 

 ing a preliminary examination of the Huerfano Basin in 1916 the author 

 secured a nearly perfect skull and jaws of one of these forms. This new speci- 

 men appears to be generically distinct from Tillotherium of Marsh and close 

 to Leidy's Trogosus, a more primitive form from the Lower Bridger, in which 

 the second pair of incisors in the lower jaw is still present. A study of the 

 new Tillodont and associated material from the uppermost Huerfano leads to 

 the belief that this horizon is slightly older than the Lower Bridger. 



The following two papers on the invertebrate paleontology and stratig- 

 raphy of the West Coast were combined into a single paper by their 

 author, who illustrated his discussion with diagrams. These papers were 

 discussed by Messrs. Matthew, Grabau, Bassler, and Miss O'Connell. 



MOLLUSCA OF THE CARRIZO CREEK BEDS AND THEIR CARIBBEAN 



AFFINITIES 



BY ROY E. DICKERSON 



(Abs'fract) 



The fauna obtained from the Tertiary beds near Carrizo Creek, San Diego 

 County, California, have yielded several unique echinoids and corals. The 

 echinoids were described by Doctor Kew two years ago, but unfortunately he 

 did not obtain any direct faunal connection with other Tertiary horizons. 

 During the past year Dr. T. Wayland Vaughan described the corals obtained 

 from these beds and he recognized the Caribbean affinities of these forms, and 

 from this study concluded that the beds were Pliocene in age. The mollusca 

 obtained by Kew. Buwalda, and English confirm Vaughan's conclusions con- 

 cerning the Caribbean affinities of this interesting group of marine inverte- 

 brates. Several species appear to be identical with forms which are charac- 

 teristic of the Gatun formations of Miocene age. 



PROPOSED CORRELATION OF THE PACIFIC AND ATLANTIC EOCENE 

 BY ROY E. DICKER SOX 



(Abs'fract) 



Identical species, similar stages of generic evolution, and the mutations of 

 Venericardia planicosta all show a much stronger relationship of the Tejon 

 group to the three lower formations of the Gulf province — ^the Midway, Wilcox, 

 and Claiborne — than was suspected. Tejon time was long and was probably 

 equivalent to Midway (in part, at least), Wilcox, and Claiborne eons. The 

 Jackson may be represented by the upper portion of the rhyolitic tuffs, the 

 clay rock of Turner. 



This study confirms and modifies somewhat the former conclusion "that the 

 Martinez is not only equivalent to a portion of the Midway, but represents a 

 still earlier stage of the Eocene as well." The generic relations between the 

 Tejon and Midway are so close that it seems probable that they are correla- 

 tive, at least in part. Possibly the Martinez is the marine equivalent of the 

 Puerco and Torrejon of New Mexico — that is, Paleocene. 



