402 Transactions. ' 



The beds below the black grit of Amuri Bluff were placed in a distinct 

 Lower Greensand formation, and the horizon of the black grit was corre- 

 lated with the coal-beds of the Waipara and all the other chief coal- 

 measures of the country. This had the effect of removing from the Cretaceo- 

 Tertiary formation the ammonites, belemnites, Trigoniae, &c. fomid so ^ 

 abundantly in the calcareous conglomerate of Amuri Bluff. In 1892 Hector 

 admitted that the Lower Greensand formation could not be maintained as a 

 distinct formation, and considered it a local expansion of the Ostrea bed of the 

 Waipara district, a view later demonstrated to be correct by Woods (1917). 



Hector's Cretaceo-Tertiary theory rested on two claims : first, that all 

 the rocks of the Waipara district from the coal-measures up to and in- 

 cluding the " grey marls " formed a single conformable " formation " and 

 palaeontological unit, and were separated from the overlying Mount Brown 

 beds by an unconformity ; and, secondly, that all the important coal- 

 measures in New Zealand, together with the conformably associated rocks, 

 belonged to the same " formation." 



As regards the first claim, Hector appears never to have studied the 

 contact of the Amuri limestone and Weka Pass stone carefully. In his 

 first account of the district he did not discriminate between the two rocks, 

 and after Hutton had made the distinction, and had claimed the contact as 

 an unconformity, emphasizmg its palaeontological importance as a plane 

 above which no Cretaceous fossils ranged, and below which no Tertiary 

 fossils occurred, Hector apparently made no special study of the contact, 

 and was content to rely on McKay's attempts to combat Hutton's criticisms. 

 He insisted strongly, however, on the existence of an unconformity between 

 the " grey marls " and the Mount Brown beds, publishing a map of the 

 Weka .Pass in support of his contention. The map was, however, little 

 more than a diagram, and does not appear to have been based on a detailed 

 survey. Hector was either miaware of, or ignored, the range of Tertiary 

 Mollusca above and below the miconformity, and made no attempt to 

 analyse their range, contenting himself with a statement of characteristic 

 species from the Cretaceo-Tertiary and higher formations, species which 

 are now known to have a considerable range above or below the rocks he 

 included in each formation. 



McKay (1887a) made a more serious attempt to meet Hutton's criti- 

 cisms. He reaffirmed the conformity of the two rocks on the ground of 

 their parellelism of dip and strike, and attributed the so-called shattering 

 of the Amuri limestone to jointing and a subsequent working-down of the 

 loose greensand into the joint-planes. He endeavoured to refute Hutton's 

 statement that pebbles of Amuri limestone were enclosed in the Weka 

 Pass greensand by publishing an analysis of a phosphatic nodule as a proof 

 that all the supposed pebbles were concretions, and he made a very strained 

 comparison of the pebbles with concretions in the Waipara greensands. 

 From later analyses it is now clear that the analysis quoted by McKay 

 referred to one of the phosphatic concretions found rarely near the contact, 

 and not to the majority of the supposed pebbles, which are only slightly 

 phosphatized, and are undoubtedly fragm^ents of Amuri limestone. McKay 

 also published an analysis of Amuri limestone which showed a high per- 

 centage of insoluble residue described as sand, and argued from this that 

 Hutton's statement that the Weka Pass stone overlapped the Amuri limestone 

 on to the old rocks on the neighbouring Mount Alexander Range had no 

 significance, as a sandy limestone might easily pass in a few miles into a 

 sandstone. Here again McKay's analysis has been shown by later chemical 

 study not to be typical of the Amuri limestone. In answer to Hutton's 



