58 
FLORIDA STATE GEOLOGICAL SURVEY. 
mastodon, probably M. floridanus. This mastodon has been 
obtained in the hard rock phosphate section from the following 
mines: T. A. Thompson, Neals, Alachua County; Dutton Phos¬ 
phate Company, plant No. 22, Juliette, Marion County; Cullen 
River Mine, Dunnellon, and Dunnellon Phosphate Company, 
plant No. 5, Hernando, Citrus County. That the mastodon is 
actually imbedded in the phosphate bearing formation is not only 
vouched for by the miners who have personally taken specimens 
from the pits, but is evident from the specimens themselves, some 
of which have the gray phosphatic sands of the phosphate forma¬ 
tion adhering to them. Associated with the mastodon is found 
the small three-toed horse, Hippcirion. The remains of the horse 
have been obtained only from the picker belt, but notwithstanding 
the fact that they have gone through the washer, some of the teeth 
still have bits of the phosphate matrix clinging to them. The 
horse remains have been obtained from the following mines: 
Franklin Phosphate Company, mine No. 2, Newberry, and T. A. 
Thompson, Neals, both in Alachua County; Dunnellon Phosphate 
Company, plant No. 6, Dunnellon, Marion County, and Dunnellon 
Phosphate Company, No. 5, Hernando, Citrus County. A number 
of other fossils have been obtained, which remain to be deter¬ 
mined. Among these are teeth of an early camel from Dunnellon 
Phosphate Company, plant No. 5, Hernando, Citrus County, and 
Cullen River Mine, Dunnellon. 
From the plants working along and near the bed of the 
Withlacoochee River have been obtained a considerable number of 
fossils. Among these, in addition to the mastodon, camel and 
early horse, is the elephant, rhinoceros and a more recent horse, as 
well as a number of other forms, some of which appear to be com¬ 
paratively recent. It is evident that a mixing of fossils has 
occurred along the river due, possibly, to the shifting of the 
channel. 
SOURCE OF THE PHOSPHORIC ACID. 
The source of the phosphoric acid is believed to be from the 
various formations that have disintegrated in situ. The Upper 
Oligocene deposits are Very generally phosphatic throughout their 
