ll^ KENDALL: TIIK (JLACIKH LAKES OF CLEVELAND. 
tlie main channel, and the new bow has been abandoned. The 
main valley continues to deepen so long as it is in use. and the 
abandoned bow will remain in singular isolation. 
The last feature which it is necessary to mention is that 
these deserted channels, as well as the other type of anomalous 
valleys (those which now carry one of the main streams of the 
district), never, or very seldom, receive any considerable tribu- 
taries : and when they do. there are usually manifest signs that 
the tributaries belong to a drainage which was on a much higher 
plane befoie the time when the anomalous valley was cut. 
The Cleveland Glacier-lakes. 
When the great ice-sheets invaded the Cleveland area, the 
mouths of all the valleys opening on to the western, northern, 
and eastern slopes were blocked with ice and their natural drain- 
age impounded, forming a series of glacier-lakes which drained 
from one to another and finalh' discharged their waters into 
Lake Pickering, the lowest of the series, the overflow of which 
passed through a gorge in the Howardian Hills, near Malton, 
into the Vale of York (Plate XIV.). 
The glacier-lakes in the Cleveland area may be divided 
into four groups : — 
(1) The North- western Lakes. 
(2) The Eskdale Series. 
(3) The Coast Lakes. 
(4) Lake Pickering. 
(1) The Xorth-westerx Lakes. 
At the period of most extensive glaciation a great press of 
ice bore in on the northern face of the Cleveland Hills. 
Denudation had at the western end swept one side of the Cleve- 
land anticlinal away, and left in its place a deep triangular recess 
overlooked by a serrated escarpment, which exposed sections 
of a number of beheaded valleys. The distribution of erratics 
and other signs show that at the maximum extension of the ice 
an overflow may have taken place by every notch of the escarp- 
ment, but of only three of these can this be positively asserted. 
Scu'jdale Lake. — At the western end of the escarpment, 
near Whorlton, is Scugdale. a valley hemmed in by lofty ridges. 
