308 Transactions.- — Geology. 



Lake Guyon is being gradually filled with alluvium, caiTied into it by the 

 streams which flow from the mountains on each side, and, indeed, it is already 

 nearly divided into two separate sheets of water by a peninsula many acres in 

 extent, which has been formed on its northei-n side by two of the largest of 

 these streams. The amount of solid matter carried into it during heavy rains 

 is enormous, and the circumstance that it has not already been filled is one of 

 extreme interest, when considered in connection with the rapid accumulation 

 of alluvium in the valley of the Dillon. 



On the lower slopes of the motintain, immediately above the col, are 

 innumerable roches moutonnees, many of them of great extent, beautifully 

 rounded in general outline, but nowhere presenting the least striation. This, 

 however, may be attributable partly to the fact that they are composed of the 

 same sandstones as the great mass of the blocks deposited on the moraine, and 

 partly to the circumstance that they weather with great rapidity under the 

 alternate action of frost and heat, the disintegrated material being removed by 

 rain. 



The general conclusions which I have arrived at from a consideration of 

 the foregoing, and other grounds, are : — ^ 



1. That the land of which the Middle Island is composed began to i-ise at 

 the close of the miocene period, and attained its greatest elevation during 

 pliocene times. 



2. That it rose to an elevation of not less than from 4,000 to 5,000 feet 

 greater than its present height above sea level. 



3. That during the period of maximum elevation the land had a quasi^ 

 continental extension, chiefly to the eastward. 



4. That during this period the land assumed its present jihysical aspect, and 

 that as it rose glaciers were formed in the great mountain valleys. 



5. That all the later marine pliocene deposits then formed were formed 

 on the outskirts of the continental area. 



6. That the glaciers, of which the evidences are to be found in those parts 

 of the Middle Island mountains to the north and south of Mount Cook, owe 

 their disappearance to a subsequent depression of the land, which continued 

 during pleistocene times, during which a fresh upheaval subsequently took 

 place. 



7. That during this depression all the later marine pliocene beds of the 

 Middle Island tract were again submerged. 



8. That the Middle Island presents no evidence whatsoever of any such 

 pleistocene glaciation as is mentioned by Dr. Haast. 



I may add that, in addition to its picturesque beauty, the tract of country 



