LIFE AT GREAT DEPTHS. 
BY PROFESSOR P. M. DUNCAN, 
Tue researches of Hooker, who obtained Polyzoa and Foramin- 
ifera in soundings at a depth of nearly four hundred fathoms off 
the icy barrier of the South Pacific, of Wallich in the Atlantic, 
and of Alphonse Milne-Edwards in the Mediterranean, have h 
much influence upon geological thought in this age, which, so far 
as geologists are concerned, is remarkably averse to theory. For 
many years before any very deep soundings had been taken with 
the view of searching the sea-bottom for life, geologists had more 
or less definite opinions concerning the deposition of organisms 
in sediments at great depths. Certainly more than thirty years , 
ago deep-sea deposits were separated by geologists from those, 
which they considered to have been formed in shallower seas. 
The finely divided sediment of strata containing Crinoids, Brach- 
iopods, Foraminifera, and simple Madreporaria, was supposed to 
have been deposited in deeper water than formations containing 
large pebbles, stones, and the mollusca whose representatives 
now live in shallows. The relations of such strata to each other 
during subsidence, the first being found occasionally to overlap the 
last, proved that there was a deeper sea-fauna in the offing of 
the old shores which were tenanted by littoral and shallow-water 
species. The deposition of strata Coil ate Foraminifera, Mad- 
reporaria, and Echinodermata, whose limestone is remarkably free 
from any foreign substances, has been considered to have taken 
place in very deep water; this theory has been founded upon the 
observations of the naturalist and mineralogist. Indeed no geol- 
ogist has hesitated in assigning a great depth to the origin of 
some deposits in the Laurentian, Silurian, or in any other forma- 
tion. The “flysch,” a great sediment of the Eocene formation, 
has been considered to have been formed at a very great depth 
and under great pressure. Its singularly unfossiliferous charac 
was supposed to be due to the absence of life at the depths of the 
ocean where the sediment collected. But this was a theory of 
the early days of geology, when the destructive influence of chem- 
ical processes in strata upon the remains of organisms in them 
was hardly admitted. 
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