110 
THREE CRUISES OF THE “ BLAKE.” 
The islands to the north of Guadeloupe form two parallel 
chains, the western consisting of Saba, St. Eustatius, St. Kitts, 
Nevis, Redonda, and Montserrat, all of which are voleanoes of 
postpliocene date; while to the eastward is a chain of volcanoes 
of tertiary age, — Sombrero, Anguilla, St. Martin, St. Barthe- 
lemy, Barbuda, and Antigua. At Guadeloupe the recent islands 
are directly united with the voleanic chain, and the still more 
modern limestones are found on its western shores. 
The miocene rocks of the greater West India Islands! have 
been, as far as observed, but little disturbed. 
beds, however, are found greatly modified. 
The geological history of Florida is in striking contrast with 
that of the greater and lesser West India Islands. The share 
which modern limestones have had in building up a portion of 
the peninsula during the most recent geological period has been 
described in the chapter on the Florida Reefs. From the obser- 
vations of Conrad, of E. A. Smith, and of Е. Hilgard, it would 
appear, as is stated by Smith,’ that up to the end of the eocene, 
the great Florida limestone plateau was still submerged ; that 
durng the time of the upper eocene, Florida was elevated 
nearly to its present height. "The axis of elevation did not 
coincide with the present dividing ridge of the peninsula, but 
occupied probably a position to the westward. From the sub- 
sequent deposition of sand, clay, and pebbles over Florida and 
parts of the adjacent States, they must have been slightly sub- 
merged again, and subsequently elevated ( during the Champlain 
period) to about their present configuration. 
In attempting to reconstruct, from the soundings,’ the state 
The cretaceous 
1 The most striking feature of the 
West India Islands as a whole is the axis 
of eruptive rocks, flanked by sedimentary 
formations and terraces of elevated coral 
On the 
northern coast of Cuba the mode of for- 
recfs and recent limestones. 
mation of the harbors within the fringing 
reef, inside of the great outside barrier 
reef, seems to prove that the rivers cut 
their way out as fast as the land was cle- 
vated and the successive terraces formed, 
It must be remembered that coral reefs 
have no such thickness as is seen on the 
terraces, but that the greater part of this 
limestone was probably deposited much 
as was the limestone that forms the back- 
bone of the Yueatan and Florida penin- 
sulas. This limestone was subsequently 
capped by reef-building corals during 
periods of rest, followed by the elevations 
to which the suecessive terraces are duc. 
2 Smith, E. A. American Journal of 
Science, April, 1881, p. 292. 
3 See the accompanying maps (Figs. 
57, 58), for which I am indebted to the 
Hon. Carlile P. Patterson, Superintendent 
U.S. Coast Survey. 
