Speight. — The Older Graveh of Xorth Canterhunj. 



269 



Aet. XXIX. — The Older Gravels of North Canterbury. 

 Bv R. Speight, M.Sc, F.G.S., Curator, Cauterbury Museum. 



{Read before the New Zealand Institute, at Chrislchurch, 4th-Sth Fehruarii, 1919 ; 

 received by Editor, 24th February, 1919 ; issued separately, 16th July, 1919.] 



Beds, and Relation to the 



Page 

 260 

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280 

 281 



Content.?. 



Introductory 



General Description of the District where the Beds are best developed 



Description of Typical Localities 



Grey River, East Branch 



Grey River, West Branch 



Okuku River and Mairaki Downs 



Kowai River, North Branch 



Kowai River, South Branch 



Fox's Creek . . 



Lower VVaipara Gorge 



Other Canterburj' Locahties 

 General Conclusions as to the Origin and Age of the 



Gravels of the Canterbury Plains 

 Bibliography 



Introductory. 



Widely distributed along the base of the Southern Alps lies a series of 

 unfossiliferous sedimentary beds, consisting for the most j^art of well- 

 stratified gravels, sands, and clays, with occasional lignite, whose position 

 has hitherto been somewhat doubtful. Haast (1879, p. 316, and map, 

 J). 370) included them in his Pareora formation, and mentioned the occur- 

 rence of lignite-beds (p. 318) in the " Moeraki " Downs, at the mouth of 

 the Waipara River, and in the Broken River basin, but hardly mentions the 

 localitv where they attain their maximum development — viz., the Mount 

 Grey Downs and the vicinity of the two branches of the Kowai River. 

 Hutton (1885, p. 211) considered them as equivalent to the Wanganui 

 system of the North Island, but remarked that they were difficult to dis- 

 tinguish from the upper gravels of the Pareora system. Park (1910, p. 252) 

 considered them older fluvio-glacial drifts. Thomson (1917, p. 411) refers to 

 them more fully, but is extremely doubtful whether they shall be assigned 

 to his Notocene or Notopleistocene set of deposits. 



Owing to the practical absence of fossils it is difficult to determine their 

 position accurately, but they nevertheless represent an interesting series, 

 and the following accoimt is intended to bring out their chief features. In 

 addition to the difficulty noted by Hutton, there is the additional one that 

 in their lithological content as well as to some extent the conditions under 

 which they were laid down they resemble the beds that overlie them, and 

 this makes it at times impossible to separate them from subsequent gravel 

 and sandv beds. 



General Description op the District where the Beds are best 



developed. 



The chief area where they are developed lies to the south-east and south 

 of Mount Grey, between the Waipara and Okuku Rivers, but they attain 

 their greatest development in the basins of the Southern Kowai and the 

 Grey Rivers. Important outliers also occur to the west of the Okuku, on 



