298 Transactioiis. — Geology. 



abundant suggestions for discussing it in the last edition of Sir Charles 

 Lyell's " Pi'inciples of Geology " ; but although the circumstances there 

 indicated, as being calculated to affect the climate of the ISToi'th Pacific, may- 

 have been instrumental, in some measure, in determining the height of the 

 snow line in the latitude of New Zealand, I am nevertheless inclined, for the 

 purposes of the present description, altogether to discard them from 

 consideration, and to look to depression alone in order to account for the 

 disappearance of the ice masses in question. 



In this connection it must be observed that, except the summits of Mount 

 Franklin (which is certainly not under 10,000 feet in height) and of a few of 

 the higher peaks by which it is immediately surrounded, no part of the 

 Middle Island range to the northward of the Mount Cook system at present 

 reaches a greater altitude than 8,500 feet above sea level. In the Mount 

 Cook system, however, it rises abruptly, attaining its greatest elevation 

 (13,600 feet)* in Mount Cook itself; whilst the lower mountains in its 

 immediate vicinity vary from 11,000 to 12,000 feet in height. It is, more- 

 over, worthy of note— having regard to the continued existence of glaciers of 

 the first order in this part of the Middle Island range — that its present 

 altitude is very much the same as that of the greater portion of the Pennine 

 Alps, a chain comprising the highest ground and the most colossal mountains 

 in Europe, and which has always been distinguished by the number and 

 extent of its glaciers, 



We are unfortunately without special data for determining the actual 

 position of the snow line in New Zealand, but many circumstances concur in 

 inducing me to adopt, for the Middle Island mountains at all events, the same 

 height above sea level as that which has been fixed by observation for the 

 Swiss Alps, namely, about 9,000 feet. But it has also been ascertained that, 

 in those portions of the latter mountains in which glaciers of the first order 

 occur, the avei-age depth of perpetual snow, talcen over the whole surface above 

 the snow line, is not less than 300 feet, and we may therefore faii'ly conclude 

 —looking to the fact that some of the glaciers of the Mount Cook system may 

 compare in extent with some of the largest of those which now occupy the 

 valleys radiating from Mont Blanc— that the snow fall and the average depth 

 of perpetual snow upon and around Mount Cook are much about the same in 

 extent as in the case of the Swiss Alps. I need scarcely say, however, that 

 these assumptions (as in the case of all others where no exact data exist) may 

 contain elements of error, but not, as I think, to such an extent as materially 

 to affect the general conclusions which I propose to deduce from them, 



* Tlie altitude of Mount Cook, as trigonometrically detennined by Mr. T. K. Hacket, 

 is 12,364 feet. I am not aware if this observation has been verified or disproved. See 

 Geological Survey Report, 1869, p, 12. — [Ed.] 



