336 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1914. 
Difficult as it may be, however, the problem is not insoluble. 
Although unfortunately the attention of oceanographers has up to 
this time been attracted rather by submarine topography, zoology, 
the physical and chemical study of sea water, and other questions, 
we begin to possess valuable data concerning the present sediments 
of ocean bottoms. It may be hoped that some day, instead of limit- 
ing the work to the epidermis of these submarine deposits, we shall 
penetrate them better by deeper and still deeper borings. 
The day when we shall energetically attack such investigations, 
an entire world will be opened to science, without doubt full of unsus- 
pected revelations: a world in which from afar we are beginning to 
discern the first confused views. 
1. PRESENT SEDIMENTATION. 
(a2) SUBMARINE TOPOGRAPHY. 
Let us pause for a moment and view the manner in which the 
sediments are deposited at the bottom of the present seas. Here 
first of all comes in submarine topography, of which we are beginning 
to have a fairly approximate idea. It has frequently been observed 
that this topography differs from that of the continents in the fact 
that a fine dust is constantly fallmg there, and being but slightly 
influenced by the currents, though agitated in shallow water, is accu- 
mulated there by gravity alone, filling little by little the hollows and 
tending toward a gradual leveling. It has been observed in this 
connection that one could go in a carriage from Brest to New York 
over the sea bottom without having any definite notion of slopes. 
This relative horizontality of sea bottoms, from which as a matter 
of course we must exclude the shores, has geologic importance; it is 
in fact, the point of departure of a convenient hypothesis, which, 
according to Sténon, dominates our geology—that of horizontal 
sediments superposed in the order of their formation and having taken 
their present slopes only through some later orogenetic or mountain- 
making movements. It is obvious, however, that this is a mere 
approximation; and. when one finds along the western coast of 
America some abysses of 4,000 to 5,000 meters depth immediately 
succeeding ranges of the same relief; when to the south of the Aleutian 
Islands or to the east of Japan, to the east of the Tonga Islands (north 
of New Zealand), to the east of Australia, and elsewhere, one falls 
abruptly into these gulfs, attaining in one case a depth of 9,700 
meters, in the presence of slopes estimated at more than 10 kilometers 
in 200 to 300 kilometers of breadth—it is no longer a question of 
gentle slopes. It is the same as regards the holes in the Caribbean 
Sea 5,200 meters deep, or on a smaller scale, those of 3,000 meters 
found 15 kilometers south of Crete, or in an opposite case, as regards 
the chain of isles rising in the midst of the Pacific like summits of a 
