Vol. 60.] GLACIAL GEOLOGY OP TASMANIA. 47 



Lyell exhibits un stratified boulder-clays, with many of the white 

 quartzite-pebbles and boulders from the conglomerates of the West- 

 Coast Range; but the clays also contain a larger number of the 

 diabase-boulders than occur in the Linda Valley, as well as some 

 sedimentary rocks, which I did not find in situ on the eastern side 

 of the King River. Following the King River to the south, glacial 

 deposits can be traced for miles down the valley. Ill-health pre- 

 vented me from examining these deposits, except from the railway- 

 train ; but their features are so distinct, that 1 have no doubt that 

 Moore was correct, in his statement that the Thureau Hills are joined 

 to Mount Owen by a moraine (see p. 41). The glacial deposits in 

 this part of the King Valley descend to the level of less than 800 feet 

 above the sea. 



The glacial evidence, at high levels, is in places remarkably 

 distinet. Mount Sedgwick consists of a peak of diabase, resting on 

 a ridge of the West-Coast Range conglomerates. This ridge runs 

 east-and-west. Well-marked roches moutonnees occur at 

 many points over the ridge near the highest peak, and the diabase 

 is glaciated in broad surfaces close to the summit. The lakes to 

 the north, in the valley between Mount Sedgwick and Mount Tyndall, 

 are bordered by small, but well-preserved moraines : one of them 

 lies round the western side of Lake Margaret. These occurrences, 

 however, are of less interest, as they are at a higher level than that 

 at which the existence of glacial action in Tasmania has been called 

 in dispute. 



With such abundant glacial evidence in the valleys, glacial 

 contours might be expected upon the hills ; but this part of 

 Tasmania has a rainfall of over 100 inches in the year. The rain- 

 fall at Lake Margaret, according to Mr. Huntly Clarke, the Engineer 

 of Supplies to the Mount-Lyell Mine, exceeds 140 inches a year. 

 Accordingly, rock-weathering takes place at a very rapid rate, 

 while the sheltered slopes of the hills are covered with dense forest. 

 I had, however, been impressed with the strikingly-glaciated aspect 

 of the northern face of Mount Owen, before I had seen the definite 

 moraine-deposits of the Linda Valley. The northern face is smooth 

 and rounded, and it has been swept bare of all drift-deposits. 

 Hence, though I had not time to search this face for glacial striae, 

 I think that it may be fairly assumed that the northern face of 

 AJount Owen was ice -worn to the height of about 1900 feet. In 

 the King Valley, close by the confluence of the King and the Linda, 

 there is a hillock of conglomerate, the shape of which has been 

 rounded by the passage of ice across it. The ends of the con- 

 glomerate-spurs immediately south of the Linda township also owe 

 their rounded surface to glacial erosion ; and a still better case of 

 glacial contours is shown by the eastern end of the spur, south of 

 the road from Linda to the Lyell Blocks Mine. 



Moreover, looking down on the ridge of schists that separates the 

 Linda Valley from the Queen Valley, I noted that it appears to have 

 been glaciated. The schists weather so rapidly that no glaciated or 



