BY A. N. LEWIS, M.C. 2S 



to a confused bed of glacial till, rising more quickly, and 

 covering the whole floor of the valley. Evidently, here the 

 glacier receded with an even movement, distributing its 

 terminal moraine equally over an area of country extend- 

 ing up to Lake Webster. 



(b) Lake Webster to Lake Seal, Including the Tarns. 

 (See Plates VL and VIL) 



From a point somewhere about the junction of the 

 Broad River with the outlet from Lake Webster, up the 

 valley to about level with the end of Lake Seal, it is diffi- 

 cult to trace any definite movements of the ice-river. The 

 whole valley is strewn with accumulations of morainal 

 material of unknown depth. The surface of the ground 

 is rendered very uneven by lines of this moraine in every 

 direction, and at all angles, and by the many boulders 

 scattered over the surface of the till. 



Lake Webster lies in a depression in this moraine. 

 It is a shallow lake seldom exceeding 10 feet in depth, and 

 overflowing over the lower slope of the morainal mass. The 

 Broad River flow^s down the eastern side of the valley, and 

 is slightly lower than the lake, from which it is separated 

 by a considerable ridge of glacial till running parallel to 

 the course of the river and the side of the lake. 



Three ice streams met in the vicinity of Lake Webster 

 to form the great Broad River glacier. From the amount 

 of work done, it appears that the glacier that flowed down 

 the Lake Seal Valley v/as the most considerable. Rising 

 in the great cirque that stands at the head of Lake Seal, and 

 fed by ice flows from the higher ridges behind, some of 

 which excavated the tarns, it conformed to the curve of 

 the valley where now Lake Seal lies, and flowing round 

 the eastern foot of Mt. Bridges until it emerged into the 

 Broad River Valley, where it was joined by a second ice 

 river flowing straight down the valley from the snow- 

 field on the ridge between Mt. Monash and Mt. Mawson. To- 

 gether, these glaciers passed on for a short distance, till 

 they were met by a smaller flow descending from Lake 

 Newdegate, and the ridges beyond, and joining the main 

 flow at the site where we now see Lake Webster. The 

 jumbled nature of the morainal deposits in this area pro- 

 bably reflects the confusion which this junction of three 

 great glaciers caused in their component ice flows. 



