BoBSON. — On the Date of the Glacial Period. 443 



Dr. Haast makes no mention of finding fossils in these strata, but suggests 

 the age as "younger tertiary (pliocene?)." In going up the Ahaura Kiver 

 excellent sections of these beds are obtained at the Big Gully, ten miles from 

 Ahaura township. The river has cut down through 400 feet, and there is 

 no sign of it having yet reached the bottom of the series. Going further up 

 the river the strata dip more to the eastward. Just before reaching Starvation 

 Point the stones get much larger, having much the appearance of an ancient 

 river bed, then suddenly the drift changes to loose sand, covered with morainic 

 matter — loose angular blocks many tons in weight lie scattered over the 

 surface. 



These drifts, both in the Grey Yalley and the Upper Buller, rise nearly 

 2000 feet above the sea level. It is in the re washes of this drift that the 

 principal alluvial workings in the Grey Valley occur. 



In the Upper Buller, near Lake Botoiti, the drift is for the most part very 

 loose, but proceeding to the northward it becomes more clayey, the stones being 

 much decomposed, forming a softish conglomerate, with intercalated beds of 

 clay and sandstone containing streaks of lignite. Although I have taken every 

 opportunity of searching for fossils in these beds, I have never yet succeeded 

 in finding any, nor have I ever heard of any being found. Judging from 

 position and general appearance, I consider the drifts must be much younger 

 than the Nelson tertiaries at the Port Hills and Jenkins' coal mine j and, 

 without very strong evidence to the contrary, I see no reason for assigning to 

 them the great age that would be necessary, adopting the hypothesis of either 

 Captain Hutton or Mr. Travers j for whether we consider the glacial period 

 to have been in older pliocene, or to have begun in miocene, times, the drift 

 being older than the glaciers must be at least miocene. I have discussed this 

 question at some length, as I believe the careful examination of the drift 

 formations of New Zealand generally will throw a great deal of light uj)on 

 many points at present unsettled, and that until the age of the drift is 

 satisfactorily settled we may speculate in vain upon the age of the glacial 

 period. 



The next question that claims attention is the general question of elevation 

 and subsequent depression, which, apart from the question of age, is common 

 to the hypotheses of Captain Hutton, Mr. Travers, and myself. A glacial 

 epoch is, no doubt, easily accounted for, by supposing an elevation of land into 

 the snow line, and the gradual extinction of- the glaciers must necessarily 

 follow a subsidence j but before this can be accepted as anything more than a 

 provisional hypothesis much more proof is required than has been put forward 

 as yet. I am inclined to consider the great drift to have been partially caused 

 by marine action, but have no evidence to bring forward in support of my 

 views, further than the similarity of the drift and gold in many of the inland 



