AKT. 10 CKETACEOUS FAUNAS OF THE CAKOLINAS — STEPHENSON" 11 



ference observed is a slightly denser crowding of the tubercles on 

 the surface of the Mississippi specimens, and this difference is so 

 slight as to be scarcely varietal. All of the specimens in both the 

 Mississippi and North Carolina collections are more or less deformed 

 by crushing and I am inclined to think that mechanical crushing 

 caused most of the so-called individual variations noted by Slocum 

 in his Mississippi specimens. 



Locality. — From the bank of Northeast Cape Fear River on the 

 west side of Hilton Park, Wilmington, just below the pump station 

 of the Clarendon Waterworks Co., New Hanover County, N. C 

 Collected by L. W. Stephenson in 1906. U. S. G. S. coll. No. 4143. 

 Geologic 'position. — Upper Cretaceous, upper part of Peedee for- 

 mation, upper part of Exogyra costata zone. European equivalent, 

 upper Senonian (Maestrichtian). 



Type material. — Part of Slocum's types in the Field Museum of 

 Natural History, Chicago, were kindly lent to me for comparison 

 with the North Carolina material, and consisted of* the following 

 nine specimens which I am informed include all of Slocum's ma- 

 terial representing this species now in the museum. 



Catalogue No. P 10457 A. 



Catalogue No. P 10457 D. 



Catalogue No. P 10457 E. 



Catalogue No. P 10457 H (?). 



Catalogue No. P 10457 K (?). 



Catalogue No. P 10458 L. (Slocum's pi. 3, figs. 5-8.) 



Catalogue No. P 10458 M. 



Catalogue No. P 10458 N. 



Catalogue No. P 10458 (?letter). 

 The specimen figured by Slocum in Plate 3, Figures 1-4, Cat. No. 

 P 10457 B, was not included among the specimens sent to me. 

 Slocum evidently had more than the nine specimens before him for 

 on page 13 of his text is a table of 20 measured specimens including 

 catalogue numbers P 10457 A, B, D, E, F, G, H, J, K, and P 10458 

 L, M, N, O, P, S, T, U, V, W, X, and these lettered specimens prob- 

 ably did not include all the material in his possession. 



Slocum describes the occurrence of the Mississippi specimens near 

 Pontotoc, Pontotoc County, in the following words : " This species 

 is from the Ripley group and is quite abundant both on the bluffs of 

 One Mile" Run and near the southern edge of the village of Pontotoc, 

 Miss. Two casts which evidently belong to this species were col- 

 lected by the writer in the Owl Creek marls in Tippah County, Miss." 

 He does not indicate at which of the two Pontotoc localities the 

 different lettered specimens were obtained. The locality on One 

 Mile Run is about a mile south of Pontotoc. 



