EVIDENCE FOR EVOLUTION FOUND IN EXTINCT MAMMALIA. 299 
Kanawha had once found an outlet to the Ohio by the way of this valley and the 
Mud and Guyandotte Rivers, yet why this ancient channel should have been 
abandoned for the present much more circuitous one had always remained a mys- 
tery until Mr. Wright furnished the key in his discovery of the great ice dam at 
Cincinnati. For it is now cler that such a barier would set back the water of the 
Kanawha until rising above the divide which have previously separated it from 
Mud River, it sent an arm across to the Ohio by way of the Guyandotte, fifty miles 
below, where the other arm and main stream reached the same river at the pres- 
ent mouth of the Kanawha, thus converting portions of Putnam, Mason and 
Cabell Counties into a large triangular island, the base of which was formed by 
the swollen Ohio, and the sides by the two arms of the Great Kanawha. The 
melting away of the Cincinnati dam withdrew the water from the western or 
Mud-Guyandotte arm of the Kanawha, leaving the abandoned valley high and 
dry, but littered up with transported trash as we now see it, while the Kanawha 
continued on to the Ohio in its present and pre-glacial outlet. 
A summary view of these and other facts in the writer's possession seem to 
prove beyond any reasonable doubt that Mr. Wright's hypothesis concerning the 
damming up of the Ohio by the glacial ice in the region of Cincinnati was an 
actual reality ; that during the period of its continuance the principal tributaries 
of the Ohio had their valleys filled with sediment carried down and dumped into 
them by the mountain torrents and other streams which drained the area south 
from the glaciated region ; that subsequently when the barrier disappeared, the 
rivers recut their channels through the silt deposits, probably by spasmodic lower- 
ing of the dam in such a manner as to leave the deposits in a series of more or 
less regular terraces which in favored localities subsequent erosion has failed to 
obliterate, though from steep slopes it has removed their every trace. 
The elevation of this dam at Cincinnati as determined from the upper limit 
of the fifth Monongahela River terrace, would be somewhere between 1050 feet 
and 1075 feet above tide, or about 625 feet above low water there in the present 
Ohio. 
THE EVIDENCE FOR EVOLUTION FOUND IN THE HISTORY OF 
EXTINCT MAMMALIA. 
PROFESSOR E. D. COPE. 
Abstract : Read in General Session, Monday, August 20th. 
The speaker, in commencing, said that the subject of evolution divided itself 
naturally into two parts — first, the question of the fact of evolution, and secondly, 
the question of the mode and active cause of evolution. The fact of evolution 
was believed by a majority of the cultivators of biological sciences at the present 
time. 
The doctrine of evolution, succinctly stated, means the doctrine of direct 
descent of organic species from pre-existent species in succession from an early 
