AOIOrav LE lf?I]?_TSi:T 3 . 



The '.vriter v^ishes to express his great indehtedneso, 

 first of all, to Mr. E. 7. "Berr^^, of the Johns Hopkins Univer- 

 sit^Z, at whose suggestion the investi^o-ation w?s initiated and 

 v.'ho h3S heen an nnfailinp- source of inspiration, as well as of 

 assistance in the solution of difficulties at every sta^^e of the 

 work; to i:i:os Julia A. Gardner, of the Johns Hopkins University, 

 for the use of the unpublished results of her extensive work 

 on the later Tertiary faunas of Virginia and the Oarolinas, 

 v/ithout 7;hich many important relations t'^mI-' vryg evaded con- 

 sideration and also for her generous assistance in the deter- 

 minations and in the interpretation of the hroad aspects of 

 the fauna; to Kr. ./. B, Olark and the other nemhers of the 

 faculty of the 'Geologic al Department for the opioortunity to 

 pursue the investigation and the training that raade it possible; 

 to i;r. .. ... Vaughan, of the United States Geological Sujrvey, 



whose suggestions were valuable because of his wealth of inform- 

 ation concerning the Antillean and adjacent regions; to Mr. '.V, 

 H. Dall and I.Ir. Paul 3artsch, of the rational I'useum, for court- 

 esies extended during freojient visits to the Kuseuni; to Hr. H. A. 

 Pilsbry, of the Philadelphia Academy of ITatur-al Sciences, for 

 c^^c-'„o3 to type riaterial; a,nd to ITr. Stanley 7/orden, of the 

 ■'aryland Geological Survey, v.ho prepared the ::aterial and '.acie 

 the nreliminary determinations. 



