38 NOTES ON THE GEOLOGY OF CRADLK MOUNTAIN DISTKICT, 



In addition to this moulding of the floor of Dove 

 Lake, the smooth curve of the eastern wall was rounded 

 O'Ut by the middle portion of the glacial stream, while 

 above, overflows made their way to the north-east. A 



large flow went past the northern end of Cradle Mt. to 

 join tlie ice in the E-odway Valley, a second passed 

 ever the ridge south of Hanson's Lake, scooping out 

 the little group of tarns there. A third passed over 



the gap into Hanson's Valley, converting the head of the 

 valley into a lake basin. The contrast between this beau- 

 tiful cirque-lake and the rugged water-cut gorge below it 

 is very striking. These three overflow-glaciers were 400ft. 

 above the present level of Dove Lake. At the northern 

 end of Dove Lake overflows of ice passed across the 

 watershed and dolerite boulders may be found high up on 

 the slopes which lead down into Smith's Ci:"eek. 



Lake Lilla owes its origin to the flow of ice that 

 came down from the Crater Lake. It is a shallow pan, 

 the greatest depth found being 45ft. The ice escaped 

 from here over a rock bar into' Dove Lake. An interest- 

 ing feature is the almost co^mplete removal of the old 

 divide between Lake Lilla and Dove Lake, the ridge be- 

 tween the two lakes rising only thirty feet above the level 

 of Dove Lake. (See Plate 4.) The outlets of the two 

 lakes are separated by a beautiful roche moutonnee hill. 

 The various strata cross this diagonally, and the surface 

 of the hill, otherwise quite smooth, is pitted with jagged 

 hollows, containing lakelets, and marking spots where 

 vast masses of rocks have been plucked out by the mov- 

 ing glacier. No better examples of this process could be 

 desired than are to be seen here. 



Crater Lake is another most interesting feature, 

 clearly exhibiting diff'erential glacial erosion. Its southern 

 end is a great cirque-wall rising more than five hundred 

 feet above the lake, and cut into a mass of rather soft 

 felspathic schist between quartzite bands. The lake 

 is here 203 feet deep. The centre of the lake is 

 crossed by a bar of quartzite only 30ft. below the 

 surface. This bar continues to the north-east of the lake, 

 forms the small knoll near the outlet, and extends down 

 to cross the outlet of Lake Lilla. The side of the knoll 

 is polished and grooved by the ice-stream from Crater 

 Lake, which passed down into Lake Lilla. The 

 gap by which this stream escaped from the Crater Lake 

 basin has been filled by a ridge of morainic material which 

 now rises about a hundred feet above the lake. The northern 

 portion of Crater Lake contains two basins, as shown 



