Remarks upon East Florida. 61 
As high as Indian River Inlet, the beach is still formed of shells, 
though less distinct and perfect in their form, mingled with some 
sand; while about Cape Carnaverel the sand predominates, until 
shelly fragments almost disappear to.the naked eye, Still, it 
seems probable that the whole beach is of a calcareous character, 
The coquina rock (as the Spaniards called it) is a formation 
found in the spits of sandy land which separate the lagoons near 
- the coast from the sea. It has been quarried in Anastasia island, 
for more than a century, affording a material for structures of all 
kinds in St. Augustine, worked with uncommon facility, and of 
a durable character. A large fort, of Spanish construction, at 
that place, is of coquina. In latitudes where there is little or no 
frost, it is, perhaps, the best material that can be used in fortifica- 
tions ; being firm enough to sustain the form: of any work, and 
receiving a shot like a plastic mass, exhibiting no fracture, and 
throwing off no splinters. 
The quarries near St. Augustine are generally about ten feet 
deep. The profile of the strata, as presented to the eye there, 
exhibits, first, a superficial covering of vegetable mould; next, 
a \ stratum of shelly fragments, quite small, and without any dis- 
tinctness of character, with no cohesion. This stratum varies 
much in thickness, according to the undulations of the surface, 
being generally from two to three feet. The next in the descend- 
ing series is a stratum of several inches thickness, composed of 
similar shelly fragments, but united in a mass by some cement. 
Then intervenes a stratum of sand, an inch or two in thickness. 
Immediately below this sand is a stratum of shelly rock, between 
two and three feet in thickness. This stratum is formed of shells 
in various states, the upper several inches being much like the 
stratum above, that is, of small and indistinct fragments, when, 
shells being perfect in their outlines, and only much abraded, and 
most of them of a size to give some clueto their species. The 
interstices in this portion of the mass are large in proportion to 
the size of the shells, and the cement which holds them together 
is hardly visible. Bivalves, cockles, of the cardium species, pre- 
dominate, while here and there is found a conch of large size, as 
also oyster fragments. Some of these conchs are several inches — 
in length, though much worn. ‘This coarse and comparatively 
unbroken deposit has a substratum, with which it is equally 
