204 E. B. Hunt on the Florida Reef. 
varying according to position, but averaging, as nearly as I could 
ascertain, about three hours. The whole rocky mass of Key 
West is of this oolite, there being on the weathered surfaces and 
occasionally in the mass a yellowish-brown crust, hard enough 
to receive a polish and usually less than a quarter of an inc 
thick. The granite foundations of Fort Taylor, Jocated in water 
of eleven feet, or less, were laid on rock which was dressed to 
form beds, by the use of a diving bell. The submarine rock 
thus examined was much like the shore rock, except that the 
materials were coarser, rather less compact and more brecciated. 
Occasional shell and coral brecciated masses are found on shore, 
ut such traces are quite rare. In removing the beach sand 
ridge which skirted the whole south shore, I found a limited 
stratum, about six inches thick and a few rods long, compose 
wholly ,of imperfectly comminuted pieces of small branching 
corals, averaging about an inch long and a third of an inch 
thick. Otherwise, this whole ridge, about ninety feet wide an 
m five to eight feet thick, above high water, was comp 
_ wholly of sand, much of which was somewhat blackened by 
vegetable loam from the ridge scrub growth. It is observable 
that this calcareous sand is scarcely at all blown about by the 
winds. Once packed, it resists the blasts of northers and hurr 
canes so completely, that at a few feet from the reverse slope 
of the beach ridge, we find only marl and rock. It presents & 
marked contrast in this respect with siliceous beach sands, which 
may, as in Provincetown, Cape Cod, build up hills a hunare 
feet high, or be carried for miles into the interior. When dry and 
freshly turned up, it blows freely, but it seems never to be movet 
by winds from the place where the sea deposits it. It is obyi0us 
that the sea is washing away the rock along the south side of 
Key West, while the north mud slope is being augmentet 
Several hundred feet of the original south beach rock have 
_ probably been cut away. 
I am indebted to Mr. Chas. Howe, now Collector at Key Wess 
for some account of an artesian well, which in 1839-40 he sunk 
to a total depth of one hundred and thirty feet, on Indian ae 
about eighty miles northeast of Key West. To the depth 
fifteen feet, the rock was moderately soft and uniform. It the® 
began to be unsound, the drill occasionally going down three oF 
four feet at once. At forty-five feet, a gravel bed of about five feet 
was found, below which the rock became harder and continued 
very solid, with a few interruptions of unsoundness, to ninety-on® 
feet, when another gravel bed of several feet was struck whic 
ve much trouble. Below this the rock became exceedingly 
hard, and was “tinged with yellow specks.” This continued a3) 
130 feet, with several interruptions by “ breaking through, the 
drill once going down five feet at one jump. The water injected 
