The lower Miocene ostracod fauna of the Caribbean area (the Gulf Coast, Central America, northern South America, the Antilles, and the Bahamas can be divided into four units: Gulf Coast, the "ashermani"-fauna (Hulingsina, Actinocythereis, Protocytheretta); Central Caribbean, the "antillea"-fauna (Loxoconcha antillea, Hemicythere antillea, Costa spp.); northern South American, the "navis"-fauna (Cativella, Caudites, Basslerites, Pellucistoma), and the more wide-spread "deformis"-fauna (Aurila, Hermanites, Jugosocythereis). These are all shallow-water assemblages. The "ashermani"-fauna spread to the south during Miocene time whereas the "antillea"-and "navis"-fauna moved northward to effect a mixing of the faunas in the Cuban and Guatemalan latitudes. The "ashermani"-fauna id not extend far south of these, and in the Quaternary withdrew northward. The "southern" faunas spread farther north, with the "antillea" element reaching Florida in the upper Miocene, and later withdrawing. The "navis"-fauna extended to the Carolinas, and at present dominates the entire region.

Relative movements of these faunas are governed by many factors, including currents, temperature, water-depth, salinity, and bottom sediment among others,

End_Page 282------------------------------

but to date sufficient evidence is unavailable for determination of the controlling factor.

End_of_Article - Last_Page 283------------