218 
FLORIDA state: geological surve:y. 
Honda, ninety miles, is undisputed. Virginia Key north of Soldier Key 
is covered with sand, but is probably underlain by the reef rock. The 
farthest northward growth of Pleistocene reef building corals known 
is to Hillsboro Inlet, ten miles north of New River. On the east side 
of the Florida Coast Line Canal, just south of the Inlet, can be seen 
fragments of large heads of reef-building corals ( Orbicella , Mae- 
andra) that were blasted out in dredging the canal. According to 
Captain Gleason, who had charge of the dredge, no coral rock was 
found in the work south of this ledge. It is possible that these heads 
formed an isolated patch a mile long and that the main reef never 
extended so far north. 
Reef rock is occasionally exposed at about low water mark on the 
south shore of Bahia Honda. To the west it shows on the south face 
of Big Pine Key and on one of the New Found Harbor Keys, though 
obscured in places by angular compactly-cemented fragments of re¬ 
cent beach rock. It does not show on any of the larger keys farther 
west, though boulders of coral rock were found, according to L. 
Agassiz, twelve feet below surface at Fort Taylor, Key West. The 
rock outcrops on Sand Key south of Key West and probably extends 
under water a considerable distance westward. Thus, the possible 
length of the Pleistocene coral reef of southern Florida was close to 
200 miles. There is no evidence to prove its maximum width. The 
maximum width shown by exposures above sea level may be three 
miles. 
Exposures:—The best exposures of the Key Largo limestone are 
in the quarry at Windleys Island where are vertical faces fourteen feet 
high. Other good exposures appear in the railroad cuts on Plantation 
Key, just east of Snake Creek, and on Key Largo south of Lake Sur¬ 
prise. The cuts and the many borrow pits show the varying structure 
of the rock and its coral origin. The bedding that characterizes most 
detrital rocks is nowhere visible. The peculiar features of the shore 
line erosion of the rock can be seen at many promontories and detached 
islets along the north side of Key Vaca. 
ke:y we;st oolitl. 
Synonymy:—The first distinctive reference to this rock appears 
to be that of G. W. Featherstonhaugh, who, at a meeting of the New 
York Lyceum of Natural History in September, 1828, exhibited 
samples of oolite from Key West. 1 2 3 
Conrad on his visit to the keys in 1847, 2 suggested the post-Plio- 
cene age of the rock. Tuomey, in 1850, 3 noted the oolite and com¬ 
biner. Jour. Sci. (1) XVI, 1829, p. 206. 
2 Conrad, T. A., op. cit., pp. 36-48. 
3 Tuomey, M., op. cit., p. 390. 
