434 Transactions. — Geology. 



Art. LVI. — The Waihao Greensands, and their Relatioii to the 



Ototara Limestone. 



By Alex. McKay, Assistant Geologist. 



{Read before the Wellington Fhilosophical Society, 20th October, 1886.] 



Differences of opinion possibly are never wanting in connection 

 with material advances in such sciences as are dependent on 

 accurate observation and sound judgment, and in this respect 

 geology in New Zealand has nothing to complain of ; for 

 whether as regards Tertiary, Secondary, or Primary formations, 

 differences of opinion exist, and have led to the necessity of 

 supporting particular views at greater length than would other- 

 wise have been needful. 



In the particular case I have to refer to on this occasion, the 

 dispute concerns localities and beds rendered classical by the 

 observations of the Hon. Mr. Mantell more than 40 years ago, 

 differences of opinion even now existing with respect to the strati- 

 graphical position of the Onekakara and Hampden beds, in the 

 Moeraki District of Otago. These beds are placed by the Geo- 

 logical Survey as belonging to the Cretaceo-tertiary series ; by 

 Sir Julius von Haast as being of older Tertiary date ; and by 

 Professor Hutton they are referred to the Upper Miocene period. 

 The Survey and v. Haast support their contentious with facts 

 both stratigraphical and palasontological ; Hutton's contentions 

 are based almost wholly on palseontological grounds. 



South of the Kakanui Kiver the beds in dispute are not over- 

 laid by the Ototara limestones of Oamaru, these being denuded 

 from the Moeraki District; but in the district north of the Kaka- 

 nui, and in Southern Canterbury, the Survey and v. Haast 

 agree in placing the equivalent beds under the Ototara lime- 

 stone ; and in the Waihao Valley it has been held that this 

 position of the greensauds can be demonstrated. Hutton admits 

 that the Waihao limestone is the equivalent of the Ototara 

 stone, or at all events belongs to the " Oamaru formation," and 

 also admits that the Waihao greensauds are the equivalents of 

 the Onekakara beds, but holds that the greensauds are younger 

 than the limestones, and, with the Onekakara beds, belong to 

 the Piireora formation. North of Timaru the same greensauds 

 occur in the valley of the Kakahu River, and here also, by 

 V. Haast and the officers of the Geological Survey, are said to 

 underlie a representative of the Ototara limestone. Hutton 

 believes that the greensand beds only appear to pass under the 

 limestones in the Kakahu, and considers them as showing this 

 apparent relationship in consequence of a fault, supposed to be 

 present, but whicli has not yet been observed. 



