ANNUAL REPORT-EARLY INVESTIGATIONS. fi3 
writer had probably not seen the papers by Agassiz and 
Joseph LeConte, since he makes no reference to them, 
although his conclusion that the limestone about Silver 
Springs is probably of the Eocene period is not in accord 
with the views of these two earlier writers. 
Professor Joseph LeConte accompanied Agassiz during 
the winter of 1851 in his explorations of the Florida Keys, 
and published a paper in 1857 supporting and developing 
the views of Pofessor Agassiz "(118). He agrees with 
Agassiz that the growth of the peninsula has been due to 
successive reefs, and that the elevation of the keys above 
water is due to wind and tide and not to elevation. 
LeConte is of the view, however, that the coral agencies 
are not alone sufficient to account for the growth of the 
peninsula, since as is well known corals do not 
grow at a greater depth than ten to twenty fathoms. To 
account for the successive reefs concentrically disposed 
from* the north to the south, he invokes the agency of the 
Gulf Stream. LeConte’s theory was that the Gulf Stream 
carried sediment which formed the foundation of the 
keys. This view necessitates the assumption that the Gulf 
Stream has shifted farther and farther to the south with 
the growth of the peninsula until it has come to occupy 
its present position. 
Hunt contributes to a knowledge of the keys in a paper 
published in 1862, republished in 1863 (103). This writer 
during a residence of five seasons at Key West, 1857-1862, 
during which time he was in charge of the construction 
of Ft. Taylor, was able to observe closely the structure 
of the keys. Hunt calls attention to the extent of the line 
of keys to the south and southwest. Hunt agrees with 
Agassiz in the view that there has been no recent eleva¬ 
tion of the keys, but objects to LeConte’s theory that 
sediment carried by the Gulf Stream forms the sub¬ 
structure. This substructure, he believes, to be formed of 
organic material resulting from shells and corals distrib¬ 
uted by a return eddy from the Gulf Stream. The ex- 
