A Rejoinder to Criticism on Hypothesis. — Spencer, iiy 
Cuba, and yet it is cut in the continental shelf substantially 
submerged to the same depth in that region as it is off Florida 
and the islands. 
On the European side of the Atlantic, professor Edward 
Hull (the retired Director of the Geological Survey of Ireland, 
and author of the Geology of Palestine including that of the 
complex Jordan — Akabah valley) has pursued the same meth- 
ods of study and interpretation of the submarine valleys as 
myself, and has published numerous papers on those off the 
European coast."^ One of the most important of his drowned 
valleys was discovered by A. Saint Clair Deville. Hull's 
conclusions are supported by professor R. Ethridge, an- 
other paleontologists, who pronounces them as ''fully demon- 
strated," thus accepting geomorphic evidence of a land fea- 
ture without the aid of fossils. Professor Hull's conclusions 
and those of his supporters are applicable to my methods, which 
professor Hull freely recognizes. 
I shall now refer to another epoch-making work, a quarto 
monograph just published by professor Fridhjof Nansent (the 
greatest Arctic explorer), on the continental shelves and 
drowned valleys, not merely of the Arctic region, but also of 
the north Atlantic, including part of the American side. Writ- 
ing of the former elevation of some of the now sunken plains, 
he says : 
"The drowned valleys and fjords at many places make this highly 
probable, and at some places . . . tliere seems no other feasible ex- 
planation to be found. .Some drowned river valleys on the American 
side of the Atlantic seem perhaps to give still better evidence of such a 
recent elevation. . . . Although Spencer's descriptions of the drowned 
valleys (i.e. southeast coast of the U. S. and in the West Indies) may 
often be based on too few and scanty soundings to be absolutely certain, 
there are evidently a good many submarine features in this region 
which cannot easily be otherwise explained, and which indicate vertical 
oscillations of great amplitude of the shore line as Prof. Spencer has 
pointed out." t 
Dr. Dall's long studies of the Tertiary mollusks seem to 
have made him overlook the import of the hollows and gullies 
in the older Tertiary limestones of Florida, which are more 
• In a series of papers published by the Victoria Institute (1S96-1902K 
t The Norwegian North Polar Expedition (1S93-1S96), vol. iv. (XIII "The 
Batiiymetrical features of the Nort'i Polar Seas, with a Discussion of the 
Continental Shelves and previous Oscillations of the Shore-line" by Fridhjof 
Nansbn, Quarto, pp. 1-232, plates 1-2J-, Christiania, 190-i). 
t Op. cit., p. 192. 
