Xiv INTRODUCTION 



the nummulitic rock or Vicksburg shell rock is the substratum, there are 

 nothing but sinks, natural wells, shallow ponds, and subterranean streams. 



" The phosphatic rock resists fire well, is easily sawed or hewn when fresh, 

 becomes hard by exposure, and is employed for the construction of chimneys. 

 From a considerable area, between the localities where it has been found in 

 place and the central depression, or relics of the great ancient central lake of 

 Florida, it has been denuded. The same agency which wore it away made 

 gullies, ravines, or channels in which clay was deposited. In this clay, which 

 in its turn exists now only in patches, generally in depressions but occasionally 

 as short ridges, the fossil bones have alone been found. There are no inverte- 

 brate remains with them. The aspect of the bones, etc., suggests that the 

 animals might have been mired in the mud on the borders of lakes or ponds, 

 and this would explain the association of the forms so far recognized. 



" Ashes and burnt clay were found under some of the bones at Hallowell's, 

 but there was after a most careful inspection no evidence to indicate any 

 human agency in this. The fire was probably due to lightning, an every-day 

 occurrence in Florida at the present time. The longitudinal splitting of the 

 long bones, sometimes ascribed to human action, in mounds and recent bone- 

 heaps, may often be the result of the penetration of roots into the interior of 

 hollow bones, which split with the growth of the root, which may afterwards 

 decay and leave no sign of its presence. I account for some split bones in the 

 collection made at Hallowell's in this way." 



