56 Transactions. 



Opposite Strauchon and Barron Rocks there is a good expanse of water, 

 and the edge of the ice reaching down into it is low and irregular, pre- 

 senting embay ments such as occur on a drowned coast-line, and no doubt 

 the ice extends forward below water-level. For these reasons it was not 

 considered advisable to measure the distance of the face from pegs Nos. 5 

 and 6, but the retreat from the line of the ice-front indicated on Bell's ma]) 

 certainly exceeds 160 metres, since the farthest exposed ice is at present 

 almost due east of peg No. 4, on Park Rock. The whole of this portion 

 <>f the face affords evidence of collapse, and the upper layers of ice show 

 shear-planes and have evidently been pushed over the lower layers, an 

 effect certainly due to differential movements ; but whether this is to be 

 attributed to the collapse of the glacier or to a definite thrust forward of 

 the upper layers of ice is quite uncertain. This phenomenon seems to be 

 more pronounced as Park Rock is approached. (See Plate XIII, fig. 1.) 



By far the greatest volume of water issuing from the glacier runs out 

 of the north-east side of the pool which fronts the ice east of Park Rock, 

 but a very considerable stream issues from close to the eastern side of the 

 glacier and runs along between the ice and the wall of the valley for over 

 400 metres. In this part of the face the retreat has been most marked of 

 all, as the measurements clearly show. 



Peg No. 7 was initially placed 2 metres from the ice; by 1912 it was 

 14 metres away, by 1914 it was 24 metres, and now it is as much as 456 

 metres distant from the peg to where the ice abuts against the eastern 

 valley- wall near river-level. The front is very high, over 20 metres in 

 this section, and there is evidence of a small advance, since the ice is 

 crowding over lichen-covered rock at the side. This advance may be of 

 local character and therefore of little importance, but it may be sympto- 

 matic of a pronounced forward movement which is impending (See 

 Plate XIII, fig. 2.) 



It will be evident from the foregoing records that the minimum retreat 

 of the face since 1909 has been 100 metres, and the maximum 456 metres, 

 and after making all due allowance for the form of the face the average 

 retreat of the front of the glacier is found to be approximately 180 metres. 



As noted previously, there are evidences of approaching advance. 

 A pulse indicating a marked rise in the ice is strongly developed about half 

 a mile (800 metres) up the glacier, and the ice is pushing over the moss- 

 covered glaciated rock-surfaces of the valley-walls at Roberts Point and 

 Cape Defiance, still farther up. (Plate XIII, figs. 1, 2.) If the rate of 

 movements of the glacier be that determined by Bell — viz., from 1 ft. to 2 ft. 

 (0-3 to 0-6 metres) per day — this pulse should reach the terminal face hi 

 from three to five years. If the rate of movement is faster, as it probably 

 is, the space of time will be correspondingly reduced, and it may be reduced 

 still more as the oncoming wave affects the ice immediately in advance of 

 it. A similar pulse is observed in the neighbouring Fox Glacier, and 

 Mr. Graham intends to place a mark in a good position on the Chancellor 

 Ridge near the glacier so that the rise of the ice-level may be correctly 

 determined. 



Mr. Graham has also made observations to arrive at the rate of flow. 

 Selected morainic blocks lying on the surface of the ice below Roberts 

 Point have shown an average movement of 3 ft. (1 metre approximately) 

 per day during a period of 200 days, and it is likely that at the base of 

 the first ice-fall the rate is much faster. Observations have been made since 

 November, 1920, but the results are not yet available. 



