ing its surface, with the accuracy of five-feet contours, will be published.
"The bed of the lake was formed by a fire that burned the trees and the peaty earth, making a hollow where the water lodged," says "general opinion."
But then it must have been a swamp before the fire, or there would have been no peaty earth to burn, and the rivers must have been flowing out of it as they do to-day. The fire could not make the rivers, even if it did make the lake; and if it were originally a swamp, the fire could not burn deep enough to form the present bed of the lake, which is from 7 to 15 feet in depth. The fires still yearly occurring never burn below two feet, for at that depth is the percolating water, and it must have been there always.
The bottom of the lake is composed almost wholly of fine white sand, and the temperature varies greatly in parts. In our long rubber boots we waded in the shallow water near the shore in several places, and found this fine sand bottom.
Prof. N. B. Webster, in an interesting article on certain physical features of the swamp, says,—
"The vast swamp appears to be retained above the level of the adjacent land in a way similar to the peat mosses of Solway and Sligo, until they
