546 GLACIER-LAKES IN THE CLEVELAND HILLS. [Aug. 1902. 
Staintondale stream, the other at the headwaters of Hayburn Beck. 
As I shall have many occasions to refer to these, I may designate the 
former Lake Staintondaie, and the latter Lake Hayburn. 
The Pye-Rigg-Slack and Rudda-Howe overflows were the first 
effects of the northern lakelet, which formed an aligned sequence 
with Lake Hayburn and drained into it. The retreat of the ice- 
margin opened an outlet for Lake Staintondale by a broad col at 
Rudda Road, where a well-marked overflow, now a swampy gully, 
exists. It is barely indicated by the 575-foot contour, and its 
intake may be at about 580 feet. Corresponding with this is an 
outlet to Lake Hayburn, Cowgate Slack, which commenced to 
trench the long spur of Hardhurst Moor at about 625 feet. I think 
that but little cutting took place before a temporary retreat of the 
ice-front freed a lower col, and the gorge called Hardhurst Slack 
was cut by the overflowing waters. This channel began operations 
at or a little below 625, and although it failed to lower its intake 
to 600 feet (namely 607), it is nevertheless a fine example of a 
glacier-lake overflow, in its lower part 40 feet deep, with very 
steep sides and almost dry. 
A slight re-advance of the ice closed the intake of this channel, and 
brought Cowgate Slack again into operation. This continued now 
to pertorm the functions of an overflow for a great length of time, 
and the channel was cut to a depth of more than 50 feet, deepening 
where it crossed the old watershed to more than 75 feet.’ 
The view into the intake of this valley (which is at 580 feet) from 
the Scarborough-and-Whitby Road near the Falcon Inn is highly 
impressive. A very diminutive stream now trickles at the bottom, 
not of sufficient volume to keep the channel clear of vegetation. 
During the period covered by the formation of Cowgate-Slack Lake, 
Lake Staintondale cut through a second col in the spur between 
the two lakes, and an overflow-channel was produced nearly on 
the line of Tofta Road. It was commenced at an altitude well 
over 625 feet, but ceased operations at over 600 feet. The 
unbroken line formed by the 600-foot contour at the Hayburn- 
Lake side shows that this overflow cannot have operated for long 
after the resumption of the Cowgate escape, and I therefore 
conclade that there was a retreat of the ice-front by which the 
two lakes became confluent. 
A further retreat of the ice-front to the eastward began to 
free the long spur bounding Lake Hayburn on the south, when a 
point was at length uncovered which was lower than the intake 
of Cowgate Slack: at that precise level a new channel began 
to be formed close against the edge of the ice —this is the 
Ringing-Keld overflow. At first it competed with Cowgate Slack 
on something like equal terms, but the narrowness of the spur 
to be cut through, and the further recession of the ice, gave a decisive 
1 T think that it may be possible for some future investigator to correlate 
the oscillations here recorded with those in the Robin-Hood’s Bay area, and 
even perhaps with that which produced the oxbow at Moss Swang, and the one 
in Hardale Slack. 
