298 Transactions.—Geology. 
abundant suggestions for discussing it in the last edition of Sir Charles 
Lyell’s “Principles of Geology”; but although the circumstances there 
indicated, as being calculated to affect the climate of the North 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 coneur 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 average depth of perpetual snow, taken over the whole surface above 
the snow line, is not less than 300 feet, and we may therefore fairly 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. І 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 T think, to such an extent as materially 
to affect the general conclusions which I propose to deduce from them, 
* The altitude of Mount Cook, as trigonometrically determined by Mr. T. R. Hacket, 
is 12,364 feet. I am not aware if this observation has been verified or disproved. See 
Geological Survey Report, 1869, p. 12.—[Ep.] 
