112 The American Geologist. August, 1904. 
5. "There is' no doubt that Cuba hao been subjected to great g20- 
logical convulsions, but that any considerable part of the island has 
been submerged since the Miocene is extremely doubtful and requires 
proof not hitherto forthcoming. 
6. "According to Mr. Vaughan's observations the great mass of the 
Tertiary limestones of Cuba are middle and upper Oligocene, ... no 
positive identification of Pliocene beds has been made, and the Pleisto- 
cene reef rocks do not occur above the sea at a greater height than 
thirty or forty feet. 
7. "The, on the whole, horizontality of the Floridian strata indicates 
a freedom from violent changes of level . . . Land shells in the Ocala 
limestones show that dr}^ land existed ; . . . elevation never exceeded 
100 feet. . . . Denudation of the organic limestones by solution rather 
than erosion is the prominent characteristic of the changes of the sur- 
face. Soft, crumbling under the finger nail, the rocks of the plateau, 
if lifted five or six thousand feet, as claimed by Dr. Spencer, would 
have been furrowed by canyons and swept bodily into the sea. Indeed, 
to me the proposition is inconceivable as a fact and incompatible with 
every geologic and paleontologic fact of south Florida which has come 
to my knowledge." 
The numbering- of the paragraphs is mine, given for ref- 
erence. 
As an elevation of about 2074 feet would connect Cuba and 
the Bahamas with Florida by isthmuses, the evidence of any 
greater elevation would have to be sought for far beyond the 
lands of the peninsula, which constitutes Dr. Ball's limitations. 
The great elevation suggested by the occurrence of the subma- 
rine valleys would certainly be startling if contemplated with- 
out study, ^^'ith me the hypothesis was of slow growth as 
twenty-five years ago I began where my friend now appears 
to be. About 1878, while investigating the problem of the 
origin of the basins of the great lakes, I found in the works of 
Dana and Dawson the evidence of a former greater elevation 
of the continental lands, but it was not until 1889, when I saw 
no other probable explanation of the submarine valleys, that 
the hypothesis of a late elevation of even 2000 or 3000 feet 
was adopted.* The same continental shelf extended from the 
gulf of St. Lawrence to the gulf of [Mexico and it was similar- 
ly indented with valleys. Yet it was another four years before 
I ventured to call attention to the continuation of the same 
features to great depths, f A year later, I published an array 
* "High Continental Elevation" etc., bv the writer. Bull. Geol. Soc. Am., 
vol. i, pp. 65-70, 1889. 
t "Terrestrial Subsidence S. E. of the Am. Cont.," Id., toI. v, p. 19 -with 
map. 
