kkxdall: tiik glacikij lakks of ( LEVKLAND. 
The anomalous overflow valleys in tlie Cleveland area are 
simple in character and easy of recognition. The deserted 
channels, having remained practically unchanged from the time 
of the departure of the ice, with all their characteristics unimpaired, 
are of singular interest and demand careful consideration. They 
are among the most impressive memorials of the Ice Age that 
our country contains. 
The Deserted Overflow Channels. 
These channels conform to four principal types in regard to- 
position : — 
(1) Direct Overflows. — These trench the watershed of a glacier- 
lake in sucli a way that the drainage takes place directly away 
from tlie ice-front. Usually only the lowest col of a given water- 
shed is trenched, except where the ice-front approached very 
near the watershed. They generally occur singly, one overflow 
serving for tlie drainage of a considerable area, but when the 
watershed is uniform in height and the ice has at one stage 
actually surmounted it. then several parallel gutters may be 
trenched on the outer slope by the watei' flowing from the ice 
itself. 
(2) Severed Spurs. — When the ice-sheet has impounded the 
waters of a valley at such an elevation that a direct overflow is 
not available, the lake will discharge its waters by a channel cut 
on the outer face of a spur along or at least parallel to the edge 
of the ice. During the retreat of the glacier a series of tliese 
notches may be cut on the face of a spur, each representing 
a halt in the retreat. 
(3) Marginal Overflows. — These are at first merely shelves- 
cut in the hillside, and developed subsequently into actual gorges. 
Some marginal overflows cease to operate before reaching the 
" gorge stage." and in the Cleveland area every stage is re- 
presented. 
In some instances a marginal overflow had its icew^ard side 
composed of moraine, and in other instances entirely of ice. 
The marginal overflows and severed spurs often are arranged in 
series, which may be of two kinds — the aligned sequence and 
the parallel sequence. 
