KENDALL : THE GLACIER LAKES OF CLEVELAND. 
15 
L-shaped lake or series of lakelets was formed. The drift in 
this area becomes thin at 600 feet and disappears altogether 
at 850 feet. Moorsholm Lake was of long duration, for its 
overflow, " Peat Holes." behind the spur of Moorsholm Rigg 
(Plate I.), is of considerable magnitude. It commenced to be 
eroded about 825 feet, and continued to be cut down almost to 
the 800-foot contour. A series of small parallel marginal channels 
round Middle Heads, the next spur to the eastward, would 
bring the overflow water from Peat Holes to the entrance of 
a fine channel. Ewe Crag Slack (Plate II.). This is a direct 
overflow into Eskdale, having the form of a great winding valley 
with its intake directed westward but soon making a sharp 
turn to the south. The first half-mile of the Slack is slight in 
inclination and occupied by a deep accumulation of peat, but 
it rapidly steepens after cutting through a thick bed of hard 
grit, and enters the valley of Black Beck (Haw-Rigg Slack), 
a normal moorland stream-course. This overflow first came 
into operation at an elevation of about 800 feet, and it was cut 
down to about 750 feet across the watershed. The usual features- 
of the meanders of overflow-gorges are seen in this valley, and 
there are lofty crags along the west side for a considerable dis- 
tance. Near the confluence with Black Beck is a great mass 
of gravel, which has yielded many erratics, including Cheviot 
porphy rites and one rhomb-porphyry. This gravel- mass then 
spreads out into Eskdale, forming two distinct terraces at the 
600-foot and 575-foot contours, representing two halts in the 
lowering of Lake Eskdale. the lower one agreeing in height 
M'ith the Commondale delta-plateau. 
A period of rather rapid retreat of the ice-margin caused 
the desertion of the Ewe Crag channel (Plate I.), and the drainage 
was conveyed by a series of marginal channels (Plates I. and 
IV.) to another great direct overflow at Stonegate, four miles- 
to the east. Along the edge of the lobe of ice that had over- 
ridden the northern watershed and formed a moraine spanning 
Eskdale at Lealholm (Plate III.), a deep overflow channel was 
initiated running down the Stonegate Valley. This channel, 
upon the retreat of the ice from the Moorsholm watershed, took 
the whole drainage of the Moorsholm lakes eastward. Hardale 
