150 BULLETIN OF THE 
In dredging for a canal now under construction on the eastern coast of 
Florida, in the waters of Mosquito Inlet, near the point known as Oak 
Hill, the engineers encountered a ridge of commingled shell and coral, 
through which they were compelled to go for a quarter of a mile or 
more in a north and south direction. The top of this ridge was some- 
what below the level of the waters of the lagoon, and presumably below 
the level of low tide in the neighboring sea. Some specimens of the 
dredging shown me by Dr. John Westcott, the President of the canal 
company, contained fragments of Manacina apparently the same as the 
living species. It thus appears certain that at least one species of the 
living reef-making coral has in recent times dwelt along the shore to 
the north of Cape Canaveral. 
The interior of the Floridian peninsula appears to be divisible into 
three distinct districts. In the south, from the northern part of Lake 
Okeechobee to Cape Sable, the surface is extremely level, formed proba- 
bly in the main of organic waste accumulated behind the coral reefs, 
upon which rests a thin and interrupted coating of current borne sands 
of inorganic origin. The only portion of this region which I have per- 
sonally seen is the edge of the Everglades, about three miles west of 
Cocoanut Grove. From the statements of Dr. Westcott and other ob- 
servers as to the frequent occurrence of limy material in the Everglade 
district, it seems to me most likely that the whole of this field above the 
sea level is substantially composed of organic materials. The northern- 
most part of the State, down into the base of the peninsula to a point 
south of St. Augustine, probably consists of an older series of rocks, 
mostly of Tertiary age, very uniformly covered by a deposit of detrital 
sands brought to the region from the northward. Going southward 
from the parallel of St. Augustine, we enter upon a region where the 
surface is underlaid by the same sandy material as that found in the 
northern part of the state, but the topography greatly changes its 
character. In the northern section, the surface is in the main of the 
gently undulating form belonging to the southern plain from Virginia 
southwards. The deposits of sand are disposed so as to create gently 
warped contours, the irregularities in height rarely exceeding ten or 
fifteen feet within any one square mile. The form is that given by 
slight marine currents where they act upon shifting sand. As we pro- 
ceed southward, the irregularities of the surface become gradually more 
and more accented, until we gradually enter on a field known as the 
Lake District, where the depressions without an outlet are so deep as 
to enclose, not shallow morasses as they do in the more northern sec- 
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