Canterbury and Westland. 387 



New Zealand Glacier period reached. These "Woolshed Hill beds 

 having, doubtless, been formed by the Great Eakaia glacier, it is 

 evident that the latter must have had truly enormons dimensions at 

 some time. We can conclude from the characteristic features of the 

 valley of the Eakaia, that during the extension of the glacier it was 

 filled with ice from side to side, and that it was hollowed or scooped 

 out in a very striking manner, principally above those localities where 

 beds of peculiar hardness crossed it. The occurrence of these very 

 hard rocks is the principal cause of the formation of Lake Coleridge. 

 "Where these beds occur we find that their remaining portions stand 

 out in very bold characteristic forms, as rocJies moutonnees, having 

 given rise to such names as Gibraltar, Sebastopol, &c. (See section 

 No. 2 on plate 7.) 



The main glacier coming down by the valley of the Eakaia, of which 

 we can trace the limits with certainty, reached into the plains a few 

 miles below Eockwood, and crossing them in a semicircular band 

 abutted against the south-eastern slopes of Mount Hutt. It is also 

 evident that the hard melaphyres, porphyries, and porphyry conglo- 

 merates stretching across the valley where at present the gorge of the 

 Eakaia is situated, formed a great barrier to the advance of the 

 glacier, until these rocks were sufficiently ground down or removed to 

 allow the glacier to advance beyond. There is also evidence that 

 when the post-pliocene glacier retreated, a large lake was for a long 

 time formed above the gorge, which in course of time was filled up 

 with glacier mud (silt), and at the same time with shingle deposits 

 brought down by the glaciers and rivers. These shingle-beds cover 

 invariably the beds of silt. The formation of the gorge is of still younger 

 origin. Morainic shelves occur also at an altitude of 500 to 600 feet on 

 the northern and 200 to 300 feet on the southern side of the Snowy Peak 

 range, thus showing the height of the glacier above the valley and its 

 general slope. The great Eakaia glacier, besides its principal outlet by the 

 main valley, had another branch descending to the plains by the valley 

 of the Selwyn, having probably had at an early period of its existence 

 very large dimensions before the barrier across the main valley, formed 

 by the porphyritic rocks, had been scooped out sufficiently by that great 

 ice-stream. Another important branch of the Eakaia glacier passed 

 along the broad opening now occupied by the Cameron river, uniting 

 with the glaciers from the Cameron and Ashburton valleys, and 

 further on with a branch of the great Eangitata glacier. The united 

 ice-stream descended the valley of the Ashburton, and reached some 



