32 Transactions. 



of conditions in the formation of the two first-named sets of beds and the 

 difference of conditions in the latter, combined with a relatively slow rate 

 of evolution throughout the whole period of deposition. Hutton (1887) 

 thus placed certain beds near Enfield and Windsor in his Pareora system, 

 correlating them on palaeontological grounds with the Awamoa beds, and 

 supposing them to occupy a valley of erosion in the Oamaru system, whereas 

 McKay (1884), from an examination of the field evidence, had placed them 

 under the Ototara limestone. Park (1887) came to a similar conclusion 

 to McKay ; and my own observations leave me in no doubt that Hutton 

 was mistaken in his account of the sequence. 



|Park, in 1905, suggested an entirely new reading of the field evidence 

 at Oamaru, designed to get over the problem, which he clearly recognized, 

 of the " Pareora fauna " above and below the limestone. Thus he corre- 

 lated, as Hutton did, the Waihao greensands, which lie below the Waihao 

 limestone, with the Awamoa beds, which lie above the Ototara limestone. 

 In consequence, he considered the Waihao limestone to represent a higher 

 horizon than the Ototara limestone. My study of the brachiopods occur- 

 ring above the limestone of Landon Creek and below the Ngapara 

 and Maerewhenua limestones could be construed in the same way to sup- 

 port Park's explanation of two distinct limestones, but the stratigTaphical 

 facts do not seem to support it, and suggest rather that the similarity of 

 the upper and lower faunas is due to the slow rate of evolution. In the 

 Waihao district the existence of the Mount Harris beds with a " Pareora 

 fauna " above the Waihao limestone is otherwise inexplicable. Park found 

 these beds resting on Lower Mesozoic beds, and, as they have a wide 

 distribution, this may be locally the case through overlap. Between 

 Mount Harris and the Waihao Eiver, however, they rest on greensands 

 resembling those of the Hutchinson Quarry beds, and these in turn rest 

 on the limestone (Thomson, 1914). This suggests strongly that the Waihao 

 limestone is the correlative of the Ototara limestone, and the Waihao 

 greensands the correlatives of the Enfield-Windsor beds. 



The only locality where Park described the two limestones developed 

 in the same section is near Kakanui. I am in full accord with Uttley's 

 interpretation of this section, contained in another paper in this volume 

 (p. 19) — viz., that there is only one limestone, which is sharply flexed 

 from the beach to the top of the hill. It is easy, however, to see how 

 any one starting off with the view that there v>^ere two limestones could 

 interpret it in the manner done by Park in a brief visit. 



Park's interpretation of the Oamaru and Waihao districts was an 

 ingenious attempt to meet a real difficulty which had long ago been stated 

 by Haast (1879), and had never been boldly faced by other geologists. It 

 had the merit of suppressing Hutton's ambiguous Pareora system, and 

 thus initiated a real advance in the classification of the Tei-tiary rocks. 

 I hope, therefore, that Professor Park will retire with honour from his in- 

 sistence on the presence of two limestones at Oamaru, and clear the way 

 for a complete accord as to the stages of the Oamaruian. Such a step 

 will not at all affect his general position as to the relationship of the 

 Tertiary and Cretaceous in New Zealand. 



With these prefatory remarks, I may now give a short generalized 

 account of the Oamaru district, based mainly on my own observations, 

 but supplemented for the coastal district by information received from 

 Mr. G. H. Uttley. 



