30 GLACIAL REMAINS IN THE NATIONAL PARK, 



Just beyond this bend is a large bed of ice-borne erratics 

 lying so thickly as to resemble a ''ploughed field" of a 

 mountain top rather than the bottom of a wide valley. 

 The head of the glacier rested on the ridge connecting Mt. 

 Monash to Mt. Mawson, where it has developed a broad 

 but shallow and "young'' cirque. This valley head is 

 shaped somewhat like a nail head, too. 



Lake Dobson lies in the western side of the head 

 of the Broad River Valley. It is a shallow sheet, lying 

 behind a slight moraine, which its outlet has cut through 

 in a deep channel. To the east of the lake rises a high 

 ridge completely covered by, if not entirely composed of, 

 glacial till, which circles west past Eagle Tarn, and then 

 east, joining the ridge south of Lake Seal, already de- 

 scribed. The lateral creases are continued across this 

 ridge, especially in the vicinity of Eagle Tarn, the out- 

 let of which, cutting through several ridges, drains through 

 a pretty gully to Lake Dobson. This whole ridge, with 

 that nearer Lake Seal, appears to be a great pressure 

 ridge formed in the V between the Broad River Valley 

 glacier and the Lake Seal Valley glacier, and was doubt- 

 less largely formed by lateral pressure from both great 

 flows. 



The moraine that dams up Lake Dobson, and the de- 

 posits that run from there a few hundred yards into the 

 Broad River Valley, appear to be the work of the last phase 

 of the glaciers, and to have been caused by a small flow from 

 the slopes of Mt. Mawson. 



This whole valley of the Broad River can be traversed 

 in an easy day's walk from Lake Fenton, and it would be 

 difficult to imagine a locality of equal size that can pro- 

 vide such a series of points of interest to a student of 

 nature or of pleasure to the picnicker. 



IL THE EASTERN GLACIAL GROUP.— (See Plates 

 IX. and X.). 



(a) The Lake Fenton Valley. 



To-day the country east of the Broad River Valley is 

 drier, and the climate milder than the country farther west, 

 and we may presume that during the ice age this condi- 

 tion prevailed in proportion So we see few glaciers on 

 the eastern slopes of the mountains. Also the snowfields 

 had far less area on which to accumulate, and the absence 



