Hardcastle. — On tJie Drift in South Canterhnrij. 311 



Art. XXX. — On the Drift in Sonth Canierhunj. 

 By J. Hardcastle. 



[Read before the riiilosophical Institute of Cantcrhury, 3rd July, 1890.] 



The Transactions of the earlier seventies show that fifteen to 

 twenty years ago the glacial or great glacier period of New 

 Zealand was a favourite topic of discussion with members of 

 the Institute. Since then the subject appears to have been 

 laid aside, though it was by no means threshed out, differences 

 of opinion remaining as to both the cause and the extent of 

 the glaciation. In the course of the controversy the following 

 remark was made by Mr. A. D. Dobson : "I believe that a 

 careful examination of the drift-formation of New Zealand 

 generally will throw a great deal of light upon many points at 

 present unsettled, and tliat until the age of the drift is satis- 

 factorily settled we may speculate in vain upon the origin of 

 the glacial period.'"''' Having long been familiar with what 

 I take to be portions of the formation Mr. Dobson referred to, 

 in South Canterbury, it occurred to me on meeting with Mr. 

 Dobson's remark recently that a few notes on the drift of this 

 district would be acceptable to members of the Institute. I 

 propose to go over somewhat wider ground than the drift- 

 formation only, sufficiently to trace, to the best of my ability, 

 its relations to the preceding and succeeding formations, and, 

 viewing the drift as the record of a particular condition of 

 climate, my notes will have special reference to the changes 

 of climate registered by the deposits dealt with. 



In the plains and downs of South Canterbury east of the 

 ranges, omitting recent and incomplete deposits, we have, in 

 descending order, — 



1. The great shingle-fans of the plains, including smaller 

 fans laid down by the smaller rivers, such as the Hare, Waihi, 

 and Opihi. 



2. An extensive but irregular deposit of loess, upon areas 

 elevated above the reach of the fan-building rivers. 



3. Sheets and streams of doleritic lavas at two points, 

 Timaru and Geraldine. 



4. The drift, a vast mass of stream-laid gravel and sand, 

 with interstratified clays and silts, the shingle highly oxidized 

 and decomposed, the whole formation greatly denuded, and 

 more or less disturbed by subterranean action. 



5. A series of fresh- water beds of totally different kind, 

 these being almost wholly of fine material. These beds also 

 show local, and almost certainly independent, disturbance. 



* Trans. N.Z. Inst., vol. vii., 1874, p. 444. 



