Vol. 68.] GLACIATION OF THE BLACK COMBE DISTEICT. 437 



When the hill-tops in this neighbourhood were first uncovered, 

 the basin south-west of Millom Park was full of ice which formed 

 a connecting-link between that of the Whicham Valley and that of 

 the Duddon Estuary. Water from this ice, held up between the 

 two living streams, seems to have been responsible for the Millom- 

 Park channels. In its escape northwards some of it fell into a 

 temporary lake, held against the hillside between the ice-streams 

 where they parted and flowed eastwards and westwards along the 

 flanks of Millom Park. On the 400-foot contour there is a shelf- 

 like feature, with sand and gravel, suggestive of a beach or delta- 

 front. 



Further withdrawal of the ice drained the lake, and the waters, 

 following the marginal slope of the ice, cut channels at a lower 

 level. Another lake was formed a little below the 300-foot 

 contour, where there is a north-eastward facing delta of sand, 

 gravel,^ and boulders, extending for quite 300 yards, with a front 

 30 feet in height. 



As we look up the hillside (down which they descend 100 feet 

 in every quarter of a mile) the empty troughs appear to be sugges- 

 tive of miniature valleys, lately occupied by miniature glaciers. 



(h) The Gill-Scar Channel. — After this episode water began 

 to accumulate in the lower part of the Whicham Valley, which was 

 now being rapidly opened up by the retreat of the Whicham- Valley 

 glacier. The more powerful stream of ice in the Duddon Estuary, 

 however, still held the low ground north-east of Millom Park. 

 The water rose to a height of about 200 feet, forming the Whicham 

 Lake, which was impounded at the mouth of the valley by a lobe 

 of the Irish-Sea ice. 



Overflow took place in a southerly direction on the eastern side 

 of Millom Park, near the margin of the Duddon ice, and the water 

 fell into what was probably another lake in the mouth of the 

 estuary north of Millom. The channel, cut by the overfl.owing 

 waters under Gill Scar, is now a fine example of a dry rock- 

 valley half a mile long. Commencing as a slight hollow, a little 

 below the 200-foot contour, it rapidly develops into a V-shaped gash 

 the floor of which crosses the 100-foot contour about a quarter of a 

 mile from its head, the valley at that point exceeding 70 feet in 

 depth. Lower down it is nearer 90. About half-way down there 

 is a step in the floor where a valley enters upon the eastern side. 



The Whicham Lake will be dealt with more fully in a subsequent 

 paragraph (p. 441). 



(c) Windy-Slack and Knott-Gill Channels. — These are 

 good examples of steeply-descending dry rock-valleys, the 

 gradients of which bear a direct relation to the gradients of the 

 glaciers wherewith they were connected. 



Windy Slack is typically V-shaped, and begins rather abruptly. 

 It is over 50 feet deep, 500 yards or more long, and its 

 floor descends 100 feet in 400 yards. It was cut in the volcanic 



1 Some pieces of Triassic sandstone were found here. 



