76 Introduction to Geology. 
destroyed many races of animals, particularly the larger car- 
nivorous quadrupeds, that then inhabited the land, and even 
some inhabitants of the waters, if we judge from the extinct 
species which we trace in this debacle. 
It has been stated, that there appears ample evidence of the 
frequent occurrence of similar catastrophes, the consequence 
of inundations more or less extensive. That to which we now 
refer was, therefore, the last of these revolutions, and modi- 
fied the form of the land as we now view it. Geologists are 
agreed in designating the mass of transported materials, re- 
sulting from that event, by the term dluvial. 
Few deposits are so interesting tothe naturalist. It contains 
not only the remains of those organic beings which then 
peopled the earth, and acquaints us with the zoology of that 
remote period, but it comprises portions derived from many 
older formations, and, on tracing these fragments to their 
original sites, enables us even to perceive the direction of this 
dilaval current. 
Remains of mammiferous animals have been discovered in 
most of the great diluvial valleys in England; nor are they 
confined to frese low sites, but have oreo heca found em- 
bedded in the gravel of our hills. 
How far all deposits of this character may be affirmed to 
be absolutely contemporaneous must remain unsettled for a 
time. It can only be decided ultimately by the physical evi- 
dence that can be brought to bear upon the question. In the 
present state of our en ledge, there seems no reason to reject 
the distinction originally made by Dr. Buckland, between the 
detritus formed by the Mosaic deluge, and hose deposits 
which accumulate from causes now in action. With respect 
to the thickness of diluvial matter, its greatest accumulation is 
probably on the coast of Norfolk where it is more than 250 ft. 
in thickness. Our sections (figs. 123. and 124.) represent 
portions of the cliffs of that county. Mr. De la Beche observed 
in Jamaica, that the diluvial gravel was from 200 to 300 ft. 
thick. In some parts of Switzerland, it is stated to be more 
than 600 ft. in depth. 
An investigation of these deposits will contribute much to 
our knowledge of the force and direction of diluvial currents. 
Mr. Farey long ago remarked, that no true theory of the 
earth or system of geology will ever be produced, which does 
not embrace a knowledge of diluvial ground equally or more 
intimate than that of ‘ all the primitive and transition coun- 
tries in the world; because, diluvium being vastly more spread 
indicates later operations on our planet, and is more within the 
reach of our investigations than the formation of mountains.” 
