PAST AND PRESENT STATUS OF THE MARINE MAJ^IMALS 

 OF SOUTH AMERICA AND THE WEST INDIES^ 



By Remington Kellogg 

 Cvnitor, Division of Mammals, U. S. National Museum 



Changes in the shore lines of the South American continent, re- 

 sulting from the submergence and subsequent elevation of areas 

 of varying extent at different times during that portion of the geo- 

 logic past known as the Tertiary period, provide a succession of sedi- 

 mentary formations from which have come an essential part of the 

 factual evidence employed by paleontologists in reconstructing the 

 history of the mammals during this period of the earth's history. 

 Some of these sedimentary strata, when examined critically, are 

 found to be ancient beaches, estuaries, and river deltas, and, what is 

 more important, to contain bones belonging to extinct types of 

 marine mammals. By means of these fossil remains the genealogical 

 history of some of these marine mammals can be traced with some 

 degree of accuracy from the time they make their appearance down 

 to the present. 



The history of the sea cows or sirenians in the Western Hemisphere 

 begins with a sirenian {Prorastomus sirenoides) of uncertain rela- 

 tionships, probably as old geologically as any of the known Middle 

 Eocene sirenians of Africa and Europe, which was found prior to 

 1855 in a calcareous sandstone nodule in the bed of a Jamaican 

 River. During the succeeding interval of geologic time, the Oligo- 

 cene, a later type of sea cow {Halitheriu'in) frequented the Carib- 

 bean Sea, the remains of one individual having been found in Puerto 

 Rico. 



No cetaceans of Oligocene age are known to occur either in the 

 West Indies or in South America. A rather varied assemblage does 

 make its appearance, however, in the Lower Miocene Patagonian 

 marine formation of Argentina. This formation has yielded two 

 distinct kinds of shark-toothed porpoises, a ziphioid beaked whale, 

 a rather dubious relative of the iniid river porpoises, a long-snouted 



^ Reprinted by permission, with change of title and extensive revisions, from Proceedings 

 of the Eighth American Scientific Congress, vol. 3, 1942. 



299 



