THE EOCENE PERIOD. 257 



The marine life. — If the Vicksburg formation be regarded as Oligo- 

 cene, the general aspect of the Eocene sea life must be regarded as con- 

 tinuing into that period. Foraminiferal deposits (of Orbitoides in partic- 

 ular) are a notable feature, corresponding in phase with the nummulitic 

 formations of the late Eocene. With these were also many pelecypods 

 and gastropods, giving a decidedly molluscan cast to the fauna. 



In the later stages of the American Oligocene, provincialism became 

 very pronounced, and the correlation of beds, even in the same province, 

 has been the subject of much difference of opinion. 1 The foraminifers 

 having greatly declined, the fauna was overwhelmingly molluscan. 



In Europe, provincialism was also very pronounced. Local and 

 transient faunas, shifting to meet the changing relations of sea and 

 land, were the characteristics of the time. No single great fauna like 

 the nummulitic of the Eocene appeared, but chiefly molluscan assem- 

 blages here and there, and now and again, as the shallow shifting phases 

 of the sea gave local embayments for temporary occupation. 



1 Details can best be reached through Dall's papers, Tertiary Fauna of Florida, 

 Trans. Wagner Free Inst, of Sci., Vol. Ill, Pts. 1-6, 1890-1903; North Am. Ter. 

 Horizons, 18th Ann. Rept. U. S. Geol. Surv., 1898, Pt. II, and the references in these, 

 and Maury's Comparison of Oligocene of Western Europe and Southern U. S., Bull. 

 Am. Pal. No. 15, Cornell Univ., 1902, and references contained. 



