784 The American Naturalist. [October, 
sustaining the testimony of the workman is of the most convinc- 
ing character. The passage from the yellow till into the blue 
till and the occurrence of occasional strata of gravel are char- 
acteristic of the glacial deposits of northern Ohio. The imple- 
ment had been subjected to oxydizing agencies characteristic of 
the deeply covered strata of that immediate vicinity. It isim- 
possible briefly to detail this evidence. We must therefore 
wait for its full publication by Professor Claypole. 
In a word, the geological situation at New London, Ohio, is 
this: The watershed between the Great Lakes and the Ohio 
is but a few miles to the south, and drains to the north through 
the main valley of Vermillion River. The land about New 
London is level for several miles, and is about two hundred 
feet below the summit of the watershed. There is no oppor- 
tunity for any disturbances to have occurred subsequent to the 
glacial period; but in the retreat of the ice from the watershed 
a temporary glacial lake doubtless occupied the upper part of 
the valley of Vermillion River, emptying its waters into a trib- 
utary of the Mohican, and thence into the Muskingum and 
the Ohio. But this lake evidently did not exist for a great 
length of time. 
Heretofore numerous flying reports of the discovery of im- 
plements in the glacial till have been made, but this is the first 
instance where the evidence has seemed in itself altogether 
convincing and satisfactory. 
RELATIVE EFFICIENCY OF ANIMALS AS 
MACHINES! 
By Manty Mites, Lansrna, Mica. 
In my paper on Energy as a Factor in Rural Economy, 
read at the Washington meeting of the Association, approxi- 
mate quantitative estimates were made of the energy expended 
1 Read in Section F. at the Buffalo meeting of the American Association of 
Science, Aug., 1896. 
