g6 FLORIDA GEOLOGICAL SURVEY-EIGHTH ANNUAL REPORT. 
molar has three transverse crests, while the third molar has four 
transverse crests and a very strong - talon or fifth crest. 
From the teeth alone this species can with difficulty be dis¬ 
tinguished from the well known Manumit amcricanum, of the Pleis¬ 
tocene. It differs, however, from; M. amcricanum in the much 
greater length of the symphysis and in the prolongation of the 
jaw in front of the molar teeth. In this respect the species resem¬ 
bles M. progcnium Hay from Nebraska. The Nebraska specimen, 
however, is obtained from deposits which are believed to be of 
Pleistocene age, while the mastodon from Florida is from the lower 
Pliocene or the upper Miocene, and it is quite improbable that the 
two mastodons belong to the same species. However, until better 
known, it is perhaps advisable to refer the Florida mastodon pro¬ 
visionally to M. progenium. 
The following are the measurements of the jaw: 
Length from back margin of symphsysis to hinder border above the 
angle _600 mm. 
Height of jaw at front of M 3 - 180 
Thickness of jaw at front of M 3 - 126 
Length of M 3 - 165 
Width of M 3 _ 85 
Length of M 2 _ no 
Width of M 2 - 80 
It has been assumed by some that the American mastodon. 
Manumit amcricanum, originated in Europe and migrated to Amer¬ 
ica. In view of the presence in the Tertiary of Florida of a 
mastodon which may well be' ancestral to< the American mas¬ 
todon this assumption becomes unnecessary, and it seems quite 
possible that Manumit amcricanum may have originated on this 
continent. 
EQUIDAE. 
HIPPARION MINOR, SP. NOV. 
PI. II, fig. IO. 
A new hipparion from Florida is of interest because of its 
miniature size. The species is represented, by teeth obtained both 
from the hard rock and from the land pebble phosphate deposits. 
As type of this species the writer selects specimen No. 5867 of the 
Florida Geological Survey collection from the pit of the Amalga¬ 
mated Phosphate Company at Brewster. In addition two smaller 
