TIIK NAUTIHS. 131 



" The products of erosion resulting from tlie rising of ihe land were probably 

 those laid down as the Grand Gulf beds of Hilgard and the Allamaha Grits of 

 Georgia. The water in which they were dej osited was for the most part fresh or 

 brackish, and the littoral subsidence so gradual as to practically exclude the sea 

 and its fauna. 



" The Pliocene of Eastern America, as understood by the writer, begins with 

 the culmination of the movement in elevation just described, and ends with the 

 beginning of the Glacial period. 



"The elevation on the continent resulted in the immediate increase of fluvial 

 erosion, and the continued and accelerated creation of perezonal formations simi- 

 lar to the above-mentioned Grand Gulf beds, especially the Lafayette or Appo- 

 mattox formation of McGee. The discharge of immense quantities of sediment 

 must have rendered the shores less adapted to profuse molluscan life than they 

 had been during the Chesapeake epoch. At all events, the Chesapeake fauna 

 seems to have receded, and to liave been gradually followed up by the warm- 

 water fauna which succeeded the Chesapeake and is preserved in the Caloosa- 

 hatchie beds. As the peninsula of Florida has preserved an unbroken record of 

 this era, it would seem appropriate to apply to it the name of the Floridian epoch, 

 and slightly modifying Prof. Heilprin's use of the term, to refer all deposits of 

 similar paleontologic contents to a single assemblage in the system under the name 

 of the Floridian group. 



It is probable that the South American vertebrates, such as Glyptodon, which 

 found their way northward after the union of the continents, did not immediately 

 reach the Floridan peninsula; but, whatever their migrations, it is certain that 

 during the Middle Pliocene they made their appearance in that region. Their 

 bones, sandwiched between fossiliferous rocks of Pliocene age, establish this fact 

 beyond controversy. 



The invertebrates appear — in Florida, at least — to have flourished peacefully, and 

 the extinction of some of the most conspicuous forms of the fauna appears to have 

 been brought about by a movement in elevation which raised their favorite shallows 

 above the sea — an elevation not necessarily of many feet in altitude. At all 

 events, a majority of those species which live preferably in moderate depths of 

 water, as opposed to littoral forms, still persists in similar situations, unmodified to 

 any notable extent. 



The orogenic independence and singular tranquillity of the area which oiginally 

 formed the island of Florida, contrast strongly with the disturbances in elevation 

 or depression of which both continental and Antillean geology give evidence. It 

 would seem almost as if Florida had rested on the axis of the disturbances, and 

 the tilting northward and southward been minimized at that point. 



For the beds exhibited in South Carolina along the Waccamaw, above the 

 Cretaceous marl, as sectionized by Tuomey and Johnson, the name of Waccama^u 

 beds may be adopted. For those which are found along the estuary of the Neuse 

 River the local Indian name of Crcatan beds may be used. Both, as will subse- 

 quently appear, may be referred to the Floridian group or epoch. The relations 

 of our later Tertiaries may be broadly summarized as follows: 



