Park. — The Great Ice Age of New Zealand. 609 



maximum refrigeration, lie ascribed the Taieri Moraine and Blue Spur 

 deposits, and to the younger tlie terminal moraines scattered throughout 

 Otago, as well as the Kaikorai and Shag Valley deposits. Hutton's view 

 has been supported by Mr. Hardcastle,* of Timaru. 



I am entirely at one with these writers in distinguishing two epochs 

 of late Tertiary glaciation in New Zealand. To the older period I ascribe 

 the Blue Spur, Taieri, and Kaikorai glacial deposits in Otago, and the great 

 andesitic boulder-till in the Rangitikei Valley in Wellington; and to the 

 later epoch the valley moraines, glacial dams, and fluvio-glacial drifts in 

 the South Island. The first was the period of maximum refrigeration, 

 causing widespread glaciation ; the second, the epoch of gigantic valley 

 glaciers, which showed many minor advances and retreats before the last 

 and final recession to the Alpine strongholds. 



The parallelism between the Glacial epochs of Great Britain and New 

 Zealand is too remarkable to be a mere coincidence, and would tend to 

 show that the refrigeration of the Pleistocene was due to some secular cause, 

 and not to local elevation, as New Zealand geologists have commonly 

 believed. 



In Europe a succession of great ice-sheets, radiating from north Norway 

 as a centre, crept over the lowlands of northern Europe, and, crossing 

 the basin of the North Sea, was met by the ice radiating from the moun- 

 tains of Great Britain. The ice-sheets from the Scandinavian glacial centre 

 also crept northward, joining the ice of the Arctic region. 



In North America four centres of glacial radiation have been recognised 

 — namely, the Greenlandian, Labradorian, Keewatin, and Cordilleran — the 

 last three being situated in the continental area somewhere between the 

 parallels 52° and 5-5° N. latitude. The Labradorian centre lay about 1,800 

 miles east of the Keewatin centre, and the Cordilleran about 1,000 miles 

 west of it. The ice-streams from these centres, though so far apart, united 

 as they spread outward, covering altogether an area of some 4,000,000 

 square miles. The Cordilleran ice - sheet crept southward to 47° N. 

 latitude ; and the Labradorian to 37° 30' N. latitude, or 1,600 miles from 

 the place of dispersion. From these glacial centres the ice-sheets also 

 spread northward, joining the advancing ice of the Arctic region. f 



The evidence seems to leave little reasonable room for doubt that the 

 Alpine region of the South Island was a centre of dispersion from which 

 ice-sheets in like manner radiated outward towards the sea on all sides. 

 The European and North American ice-sheets deployed northward, joining 

 the Arctic ice. There seem to be no valid grounds for supposing that the 

 New Zealand ice-sheets did not spread southward and join the advancing 

 Antarctic ice. 



Criteria of Glaciation. 



Having thus reviewed the evidences of ancient glaciation presented in 

 New Zealand, more particularly as seen in Otago and on the east coast 

 of the South Island, and in the Provincial District of Wellington, we are 

 better able to determine the value of the criteria of an ice-sheet mentioned 

 by Dr. Marshall. He places these criteria under five headings, which I 

 propose to consider seriatim : — 



(1.) A continuous line of morainic deposits at the extreme limit of 

 the ice-sheet. 



* Hardca,stle, Trans. N.Z. Inst., vol. xxiii, p. 311. 

 t Chaniberlin and Salisbury, " Geology," vol. iii, p. 331. 

 20— Trans. 



