308 CORALS AND CORAL ISLANDS. 
demonstrated the correspondence existing between this south- 
ern fauna and that of the tract lying to the south. But more 
significant is the finding of the large assemblage of mamma- 
lian remains which have been lately brought to light from 
various parts of the peninsula. These have been determined 
by Dr. Leidy* to be the skeletal parts of the elephant, masto- 
don, llama, rhinoceros, tapir, Hippotherium, the sabre-toothed 
tiger (Machzerodus), Glyptodon, etc. Neither the Sabre-tooth 
nor the Glyptodon, both of which are so closely related to the 
commoner South American forms as to be barely distinguish- 
able from them, have heretofore been found in the south- 
ern United States. Of course they may yet be found, and 
indicate a passage over from South America by way of Mex- 
ico and the southern United States. But the great abund- 
ance of these remains on the Floridian peninsula, and their 
absence, either in whole or part, from the Gulf States, are 
facts which, so far as they go, point to a former direct land- 
connection across what is now an arm of the Gulf.” 
Concrusion. — With the theory of abrasion and solution 
to make lagoon-basins and the deep channels inside of barriers 
incompetent, and also that of current-drift, all the hypotheses 
of objectors to Darwin’s theory are alike weak ; for they have 
made these processes their reliance, whether appealing to a 
calcareous, or volcanic, or pelagic-growth, or mountain-peak 
basement for the structure. The subsidence which the Dar- 
winian theory requires has not been opposed by the mention 
of any fact at variance with it. nor by setting aside the argu- 
ments in its favor; and it has found new support in the facts 
from the “Challenger’s”’ soundings off Tahiti that had been 
put in array against it, and strong corroboration in the evi- 
dences of subsidence from the West Indies. 
1 Leidy, Proceedings of the Academy of Natural Sciences of Philadelphia, 
1884-1889. 

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