272 CAPI. p. W. HUTTON Olf THE GEOLOGICAL POSITION 



limestone upon which they rest, and the unconformity therefore is 

 not due to local causes, but is the result of a general denudation. 



Amuri. — Here we get another section showing the Amuri lime- 

 stone covered by the Grey Marl (fig. 5). Dr. von Haast thinks that 



Pig. 5. — Section through Amuri South Bluff. 

 (Distance one mile.) 



5 3 1 



For explanation see fig. 1. 



the Grrey Marl (called Leda-beds) has, at the South Bluff, been 

 deposited in sequence on the Amuri limestone * ; but he makes a 

 difference in the dip of the two rocks. For 'in his section he shows 

 the limestone dipping E. 70°, and on p. 38 of his report he says 

 that the Grey Marl dips S.E. 48° to 22°. At the same locality I 

 found, like Dr. von Haast, that the Amuri limestone dipped E. 70°, 

 and that the Grey Marl in contact with it dipped E.S.E. 45°, 

 gradually changing to S.E. 15°; thus indicating an unconformity, 

 although the actual junction of the two rocks was not seen. 



According to Mr. M'Kay, a bed of " green-sand conglomerate " 

 comes between the Amuri limestone and the Grey Marl, which he 

 supposes to represent the Weka-pass Stone t. He* has no doubt 

 that all are conformable and belong to one system, but he makes 

 the Amuri limestone to dip E.S.E. 45° J, and the Grey Marl to dip 

 S.E. 45° to 15°. He also shows that the Amuri limestone thins out 

 in a distance of about a mile, from 630 feet at South Bluff to 330 

 feet at Amuri Bluff, while the underlying beds belonging to the 

 Waipara System retain their thickness, or even get thicker §. In 

 a bed of argillaceous limestone with flints, which extends from the 

 Waipara to Cape Campbell, this rapid local thinning in the middle 

 of its length looks much like the result of denudation. 



^o fossils had been described from the Grey Marl at this locality 

 when I wrote my report, and I placed it in the Pareora System 

 (Miocene) because the rocks in the Conway were supposed to be of 

 that age. Since then Dr. Hector has found Pecten Zittelli and other 

 fossils in it which would make it probably the same bed as the 

 Grey Marl of the Weka Pass. 



* ' Geological Reports,' 1870-71, p. 37. 



t This is the " Pucoidal limestone " of Dr. Hector (Geol. Eeports, 1873-74, 

 p. xi), which he places below Weka-pass Stone (Geol. Eeports, 1877-78, p. 192). 

 Mr. M'Kay obtained bones of 'Palceeudyptes antarcticus, Huxley, from it. 



\ Judging from this dip Mr. M'Kay appears to consider as Amuri Hme- 

 stone the same beds that I consider to be Grey Marl ; and this may account for 

 his statement that Pecten Zittelli occurs in the former rock. 



§ ' Geological Eeports,' 1874-76, p. 178. 



