352 



T. W. STA>^TON CRETACEOUS-TERTIARY BOUNDARY 



ber of species identical with Fox Hills forms, others that are closely re- 

 lated, a few that were ascribed to the Fox Hills, but apparently were 

 actually collected by the early explorers from beds now assigned the ma- 

 rine member of the Lance, and a considerable number of new species, 

 which so far as known do not occur outside of the marine member. 

 The list of fomis recognized is as follows : 



Nodosaria sp. 



Caryophyllia f sp. 



Anomia sp. 



Perna sp. 



Crenella sp. 

 *Cucullwa shumardi M. and H. 

 ^Glycimeris suMmht'lcata {M.a.nd. H.) 

 *Leda (Yoldia) scitula M. and H. 

 *Leda equilateralis M. and H.? 

 *Nucula planimarginata M. and H. 

 tCrassatellites evansi (H. and M.) 



Solemya ? sp. 

 :*Lucina occidentalis (Morton) 



Corhicula cytheriformis M and H. 

 ^Cyprina ovata M. and H. 

 *Cyprina ovata var. compressa M. 

 and H.? 



Veniella ? sp. 



Callista sp. a. 



Callista sp. b. 



Tellina f sp. 



Thracia sp., related to T. suh gra- 

 cilis Whitfield 

 iTeredo glohosa M. and H. 



^Teredo selliformis M. and H. 

 Corhula sp. 

 Entails sp. 

 Scala f sp. 

 Turritella ? sp. 

 f.*Lunatia concinna (H. and M.) 



Ccrithium f sp. 

 %*Ancliura americana (E. and S.) 

 Anchiira americana (E. and S.), 



robust variety. 

 Helicaulax ? sp. 

 i*Cantharus (Cantharulus) vaughani 

 M. and H. 

 *Pyrifusus (Neptunella) newberryi 



M. and H.? 

 =^Fusciolaria huccinoides M and H. 

 *Fasciolaria (Piestochilus) culhert- 



soni M. and H. 

 *Turris contortus M. and H. 

 Turris sp., related to T. contortus 



M. and H. 

 '^Turris minor (E. and S.)? 

 Cinulia sp. 

 *Cylichna scitula M. and H.? 



In this list of about 40 forms there are 21 named species and varieties, 

 of which 15 (marked *) occur in the Fox Hills, 4 (marked X) occur in 

 the Pierre, and 5 (marked \) were originally described from rocks now 

 known to belong to the marine member of the Lanco. One species, Cor- 

 hintla rytheri formic, was described from tlie Juditli River, and is known 

 in the Mesaverde and the Lance of other areas. The fossil seaweed, Hah/- 

 wenites major, which is common in the Fox Hills and other sandy forma- 

 tions of the marine Cretaceous, is also associated with the above listed 

 fauna. 



The fauna lacks a number of cim-inion Fox Hills species and contains 

 a considerable proportion of new forms, so that it may be called a modi- 

 fied Fox Hills fauna. It gives evidence that the Tretaceous Sea had not 

 yet finally retreated from the province, and it may reasonably be sup- 

 posed that in some area not far away, probably on the east or southeast. 



