146 The American Geologist. March, 1904. 
"I rim entirely unable to accept Dr. Spencer's hypotheses; while ad- 
mitting many of the facts he brings forward, I am convinced that they 
admit of some other explanation. We find in the Oligocene of Bowden, 
landshells belonging to groups peculiar to and now inhabiting the island 
of Jamaica, which is sufficient evidence that since the era during which 
the Bowden marl was deposited, the island has never been entirely sub- 
merged. With Cuba it may be different, though I can hardly bring my- 
self to believe that the peculiar land,shell fauna which is so characteristic 
of that island can have been evolved since the Pleistocene. However, 
this question is apart from those we have to consider here. 
"The proximity of Cuba to Florida and the fact that the adjacent 
portions are composed of organic limestones, which has long been 
known, led to the very natural but erroneous inference that Cuba and 
the peninsula were formerly continuous, and that the Florida Strait 
had been cut between them by the erosion due to weather and streams, 
and subsequently by the Gulf Stream. 
"There is no doubt Cuba has been subjected to great geological con- 
vulsions, but that any considerable part of the island has been sub- 
merged since the beginning of the Miocene seems extremely doubtful 
and requires proof not hitherto forthcoming. 
"According to Mr. Vaughan's observations the great mass of the 
Tertiary limestones of Cuba are middle and upper Oligocene, ranging 
from the Chattahoochee to the Bowden or its equivalent. The Vicks- 
burgian and the Miocene are alike absent, no positive identification of 
Pliocene beds has been made, and the Pleistocene reef rocks do not oc- 
cur above the sea at a greater height than thirty or forty feet. 
"The, on the whole, remarkable horizontality of the Floridian strata 
indicates a freedom from violent changes of level from the time the 
peninsular limestone first emerged from the sea. Landshells in the 
Ocala limestone show that then dry land existed. South of the Suwan- 
nee Strait, closed in late Miocene times, there is no evidence of sub- 
sequent submersion to any serious extent. Two gentle flexures run par- 
allel with the peninsula, having the lake district between them; a tilting 
of, at the most, thirty feet, up at the east, down at the west, which may 
have been contemporaneous with the flexures ; and, for the rest, very 
slow and slight but probably nearly continuous elevation never exceeding 
one hundred feet and perhaps less than half that, with dry land and 
fresh-water lakes constantly existing since the Ocala islands were raised 
above the sea ; such is the geological history of the Florida peninsula. 
Denundation of the organic limestones by solution rather than erosion is 
the prominent characteristic of the changes in the surface. Soft, crumb- 
ling under the finger-nail, the rocks of the plateau, if lifted five or six 
thousand feet, as claimed by Dr. Spencer, would have beeen furrowed 
by cafions and swept bodily into the sea. Indeed, to me the proposition 
is inconceivable as a fact and incompatible with every geologic and pale- 
ontologic fact of south Florida which has come to my knowledge. 
"The development of the geological characteristics of the peninsula, 
the approximate mapping of its formations, are features of the work 
