Marshall. — The Glaciation of New Zealand. 335 



Further north the ice extended some distance westward from the foot 

 of the mountain-range. The terminal moraines now form the coast-Hne at 

 intervals between Ross and Milford Sound, and are not far inland at Hoki- 

 tika and Grey mouth. 



These limits of glaciation have been recognised for a long time, and 

 have been embodied in a map published by the Glaciation Research Com- 

 mittee of the Australasian Association for the Advancement of Science. 



In a recent bulletin of the New Zealand Geological Survey, No. 7, p. 25, 

 the following statements are made : " The features of the land in the 

 Wakatipu region, and from there southwards to the plains of Southland 

 and eastwards to the sea, are everywhere dominated by evidences of 

 ice erosion on a scale of magnificence that is unknown elsewhere in the 

 Southern Hemisphere, and is perhaps without a parallel elsewhere outside 

 of the polar regions. Each valley and depression contained its own glacier, 

 biit all were united in one, forming part of the great ice-sheet that covered 

 the land. Its surface formed a vast plateau through which the tops of the 

 highest peaks appeared, looking like lonely islets in a frozen sea. A 

 striking feature of this gigantic glaciation is the remarkable freshness of 

 the ice-grooved surfaces, the beautiful flowing contours being everywhere 

 sharply outlined in their carpets of native grasses." 



P. 40 : " Evidences of a continuous ice-sheet can be traced along the 

 main axial divide until we reach Boulder Lake, in Collingwood County. 

 The smooth, rounded contours of the ranges between Wakatipu and the 

 sea, the thick sheet of boulder-clay covering the Henley Hills and the area 

 between Saddle Hill and Dunedin, and the silts and glacial till covering the 

 Timaru and Oamaru areas afford convincing proof that the glaciers also 

 reached the sea on the east coast. The ice-sheet appears to have reached 

 its northern limit near Cook Strait." 



P. 43 : " The Henley deposit is undoubtedly of glacial origin. It is 

 not a terminal moraine, but a true boulder-clay, the formation of which 

 appears to have been partly subglacial and partly subaqueous. A sheet of 

 boulder-clay of great interest covers all the hills and ridges between Dun- 

 edin and Saddle Hill. It consists of stiff yellow clay, which often contains 

 boulders of basalt, phonolite, dolerite, and other igneous rocks." "• The 

 question may now be asked. Was the great ice plateau that covered the 

 South Island of New Zealand an extension of the polar ice-sheet ? It is 

 almost certain that this must be answered in the affirmative, for whatever 

 cause or causes originated the glacial period in New Zealand would also 

 operate in the higher latitudes. The exploring expedition of last November 

 proved that the Auckland and Campbell Islands had suffered erosion by 

 an overriding sheet of ice that must have had a polar origin." 



The only evidences that are offered \n support of these sweeping state- 

 ments in the publication are contained in the above extracts and in a de- 

 tailed statement of the thickness of the ice in the Wakatipu basin. This is 

 estimated to have been 7,400 ft. 



It is advisable here to state the nature of the criteria some or all of 

 which are usually employed in defining the limits of a prehistoric ice- 

 sheet : — 



(1.) A more or less continuous line of morainic deposits at thB ex- 

 treme limit of the ice-sheet. 

 (2.) The occurrence of till or boulder-clay over almost the whole 

 area that was covered by the ice-sheet. 



