§3 
wool, was capable of enduring, and probably preferred a 
subarctic climate, and was associated in this country as in 
Europe, with the musk ox and the reindeer. We may there- 
fore infer that a progressive increase in the animal tempera- 
ture, drove most of the animals of the Forest-bed northward, 
and caused to gather on the shores of the Arctic sea, the 
herds of Elephants whose remains so much impress all travel- 
ers who visit that region. 
This was probably the scene of the last vigorous and 
abundant life, and of the death of the species; an event con- 
sequent perhaps on the action of local causes, which we shall 
comprehend when we have opportunities of studying the 
record. 
One remarkable statement in regard to the Forest-bed re- 
quires notice. In more than one instance, parties digging 
wells in South-western Ohio, have reported not only that they 
found a black soil and logs, but that ‘some of these logs bore 
marks of the axe, and were surrounded with chips.” These 
stories I formerly rejected as pure fabrications, but in the 
light of recent observations, they seem to me to be in part 
true, and not difficult of explanation. 
Prof, Orton reports the finding of the teeth of Castoroides, 
in connection with the peat bog of which he has given an in- 
teresting description in the J ournal of Science, for July, 1870. 
Now we know that the great dental chisels of Casior and 
Castoroides are exclusively employed in felling and cutting 
up timber, and wherever these animals have lived, some 
traces of their work must almost necessarily be found. In 
Arizona at one of our camps on the San Juan River, I 
measured three cottonwood trees cut by beavers, within fifty 
feet of our camp-fire. All these were over two and a half 
feet in diameter above where cut. In the vicinity were acres 
of bottom-land, once heavily timbered, now cleaned as if by 
the hand of man. There the logs and chips quite covered 
the ground. As the Castoroides was more than. double the 
size of the largest living beaver, his prowess as a wood-cutter 
must have been proportionably greater, and I am disposed to 
