SUBMARINE DEPOSITS. 261 
The constant working over of the loose material by the waves 
and currents along every part of the coast line is repeated on a 
larger scale upon the continental shelf of our Atlantic coast. 
There the results depend, not only on the nature of the materi- 
als of the adjoining coast, but also upon the distance from shore, 
the depth, the slope of the coast, and the character of the bot- 
tom, and of the animals and plants living upon it and in the 
surface waters. 
Mr. Murray ' of the * Challenger " has paid special attention 
to the bottom deposits, and we dra freely from his papers 
in the sketch which we give of the various kinds of bottoms he 
has recognized, as well as of the interesting views he holds on 
the nature and origin of oceanic deposits. The subject as a 
whole was first treated by Mr. Murray, to whom in connection 
with the Abbé Renard we owe a connected sketch of deep-sea 
formations. 
Our knowledge of marine deposits was formerly limited to 
those of shallow waters. Attention was paid only to specimens 
which could be collected by the Stellwagen cup, commonly used 
for inshore hydrographic purposes. Our older charts contained 
at best only meagre information regarding the most character- 
istic shore deposits. From the stüdy of Gian we were able to 
obtain a general idea of the nature of deposits on the inshore 
plateau of the continental shelf, derived from materials con- 
stantly subjected under very special conditions to the action of 
the tides, waves, and currents. We could of course find no clue 
to the conditions under which deposits were taking place in the 
immense abyssal basins, thousands of miles in extent, that occupy 
certain areas both in the Pacific and Atlantic, far away from any 
continental mass. As soon, however, as samples of the bottom 
were obtained from these great depths, a new chapter was 
opened in thalassography. An examination of these samples 
has given us the first comprehensive sketch of deep-sea deposits. 
1 Mr. John Murray, to whom the spe- the shores of the Greater and Lesser An- 
eimens of bottom deposits collected by tilles ; and, finally, from the zulf of 
the “Blake” were sent for examination, Mexico and Straits of Florida. Analyses 
has described in detail some typical spe- of the characteristic deposits will be found 
cimens from the coast between the Gulf in the Bulletin of the Museum, Vol. X. 
of Maine and Cape Hatteras; between No. 2. 
Cape Hatteras and Lat. 31? 48' N. ; from 
