50 GEOLOGICAL NOTES OX KOSCIUSKO, 



blocks of rock in the moraine are mostly of granite, but slate 

 and quartzite fragments are numerous. The last-mentioned, of 

 course, retain the stri?e best. Two of these are now exhibited. 

 (See Plates viii.-ix.). 



The blocks are mostly from about 9 inches up to 1 J feet in 

 diameter, occasionally as much as 5 feet. All the fragments of 

 quartzite and slate examined showed glacial markings. 



If this moraine be viewed from a distance of three-quarters of 

 a mile to the S.W., it will be seen that it is apparently confluent 

 with the closely crowded group of terminal moraines immediately 

 below Hedley Tarn. It was not clear to us as to whether it 

 should be regarded as a lateral, median or terminal moraine. The 

 grooves on the glaciated granite surface immediately N. of the 

 moraine trend, as already stated from N. 40' W. towards S. 40° 

 E., whereas the general trend of the moraine is W. 6° N. and E. 

 6° S., so that the ice which glaciated the granite beneath the 

 moraine appears to have moved at an angle of about 45° to the 

 general trend of the moraine. More observation is needed for 

 the correct interpretation of the mode of origin of this remark- 

 able and beautifully preserved moraine. 



About one-quarter of a mile below the outlet to Lake Mere- 

 wether, the grooves on some of the large blocks of granite in the 

 ground moraine trend S. 35° E., and at a point a little further 

 down the valley, and about 300 yards above the upper end of 

 Hedley Tarn, and a few chains to the S.W. of the creek flowing 

 from Lake Merewether to Hedley Tarn, the surface of the granite, 

 where it emerges from beneath the morainic material, shows 

 abundant evidence of having been powerfully ground down and 

 grooved by moving glacier ice. The grooves may be traced right 

 up the shoulder of the ridge to the west of Hedley Tarn to an 

 altitude of about 6,380 feet, whereas the level of Hedley Tarn is 

 about 6,110 feet. This shows that the glacier ice was at least as 

 thick as the difference in level between these points, viz., 270 feet. 



As, however, the rocks are deeply grooved up to 270 feet above 

 Hedley Tarn, allowance must be made for a further thickness of 

 glacier ice suflicient to supply the necessary pressure for the 



