Speight. — Structural and Glacial Features of Hurunui Valley. 101 



emphasized by the marked dependence of the landscape forms on the features 

 resulting immediately from these movements. In some cases time has not 

 been sufficient for the weak covering beds to be removed from the higher 

 elevations, though in general these are more, perfectly preserved in the folded 

 and faulted intermonts. The movements producing these must have been 

 slow, although they have been comparatively recent, since the main stream 

 has preserved its original direction with but slight modifications, in spite 

 of- the opportunities presented for departing from it as a result of these 

 movements, while farther north in the Kaikoura region the movements 

 were on such a scale that the stream-systems are almost entirely dependent 

 on them for their direction. The Hurunui region thus illustrates the con- 

 dition that a powerful stream may at times maintain its original direction 

 in spite of strong forces tending to deflect it. Dr. Cotton has drawn my 

 attention to a paragraph in a paper by Professor W. M. Davis, entitled 

 " An Excursion in Bosnia, Hercegovina. and Dalmatia," * which seems 

 appropriate in this connection. It reads as follows : It is evident that 

 this hypothesis [warping] accounts simply enough for the occurrence of 

 irregularly alternating basins and uplands ; and that the basins thus pro- 

 duced might lie connected by gorges eroded through the uplands by the 

 master rivers : the gorges marking either the paths of antecedent streams 

 that had maintained their course in spite of the warping, or paths selected 

 by the drainage consequent on some early stage of warping and antecedent 

 to the rest." This idea of anteconsequent streams has been elaborated 

 by Cotton (1917. p. 253), and it seems entirely applicable to the case of the 

 Hurunui. except that faulting has ensued as a result of the strains set up 

 in the warping movements. 



Glacial Features of the Hurunui Valley. 

 (See map, fig. 2.) 

 Although there are no present-day glaciers in the valley of the Hurunui, 

 the mountains not being sufficiently high in that part of the alpine region 

 to intercept sufficient snow to feed them, the upper part of its basin was 

 subjected to the severe glaciation which affected a large part of the South 

 Island of New Zealand in Pleistocene times and perhaps later. Haast has 

 indicated (1879, plate 11) that the Hurunui Glacier at its greatest exten- 

 sion came down below the junction of the Waitohi River with the main 

 stream — that is, well on to the Culverden Plains ; but on what evidence he 

 bases this meat extension is not clear, and in my opinion there is no reason 

 to demand it. The absence of morainic and other glacial deposits, as well 

 as the form of the river-valleys in the middle course of the Hurunui, render 

 his supposition very improbable. Especially is the latter evidence strong 

 in the case of Maori Gully, the striking gorge which the river has cut in the 

 edge of the high-mountain country before it runs through the foothills of 

 the Alps. This is so deep and narrow that it is almost impossible that ice 

 could have come through it and left it in its present condition. It seems 

 to me extremely probable that the ice did not extend below the junction 

 of the two main branches of the river, if. indeed, it came so far, since there 

 is no proof of its former presence even at this point except the somewhat 

 indefinite evidence based on the form of the river-valley, which may be 

 attributable to ice action or may be the result of ordinary stream erosion. 

 In the absence of other proof this solitary line of evidence must be viewed 

 with considerable reserve. 



Bull. Grog. Soc. Philadelphia, vol. :L No. 2, pp. 21-60, 1001. 



