102 Transac/io/is. 



corresponding basal portions of these Oamaruian limestones to appear at 

 very unequal heights above sea-level, whilst from many areas they have 

 been removed by erosion, leaving the Mesozoic rocks exposed. The pre- 

 Oamaruian surface of these last can only be surmised, for the evidence 

 obtained is inconclusive, but it certainly appears to have possessed the 

 broadness and simplicity so noticeable in the pre-Notocene surfaces of other 

 parts of New Zealand.* 



Whatever may have been this surface, upon it was deposited the basal 

 limestone, and then a sequence of marls, blue sandstones, and impure fine- 

 grained limestones. Then came the gentle folding, or warping, with the 

 accompanying minor faulting that has already been noted — movements 

 that probably accompanied a period of relative land-elevation, evidenced 

 near the Kawa Creek by the sharp planation of the edges of the upper 

 beds of the Notocene sequence either by marine or subaerial erosion. The 

 reverse swing of the oscillation now caused this surface of planation to be 

 covered up by the fossiliferous marine sands that furnish one of the main 

 objects of this article. Their fossils show that they are practically the 

 uppermost Notocene, and it is probable that they are comparable with 

 certain massive sandstones, discovered recently by Dr. Henderson in the 

 Te Kuiti district, which unconformably overlie the upper beds of the 

 Tertiary sequence in that area.t 



The closing members of the succession at the Kawa are not without 

 interest, and may now be given. Unconformably above the fossiliferous 

 sands is a local basaltic accumulation (both lava and agglomerate), followed 

 by about 30 ft. of fresh-water silts, in which are intercalated a few thin, 

 impure lignite-seams. Above these is a similar thickness of sands which 

 appear to be wind-bedded ; then a bed of pumice silt — itself a most interest- 

 ing discovery — which is followed by ancient dune sands rising to a height 

 of nearly 400 ft. above sea-level, and more or less continuous north-west to 

 Port Waikato. 



Details of the Coastal Section near Kawa Creek. 



Without entering upon a discussion of the relative merits of different 

 lines of evidence in the correlation of the New Zealand Notocene beds, or 

 of the vexed cjuestion of the substantial conformity or otherwise of these 

 strata, the writer considers that in the instance he is describing the mutual 

 stratigraphic relations of the beds have a very real importance. The 

 physical unconformity is very marked, and if it is coeval with that described 

 by Dr. Henderson in the Te Kuiti districtt it will no doubt serve a useful 

 ])urpose in the classification of the latest Notocene strata of a wide district, 

 if not of New Zealand. It seems desirable, therefore, to set forth in greater 

 detail the observed section near the mouth of the Kawa Creek in which this 

 unconformity is evident. 



It may be remarked, further, that there is a very definite disconforraity 

 evident in the sea-cliffs immediately south of the Waikawau Stream, which 

 is several miles north of the Kawa Creek, but this is in beds much below 

 those at the latter locality. 



* See, for example, C. A. Cotton, The Structure and Later Geological History 

 of New Zealand, Geol. May., dec. 6, vol. 3, pp. 2-48-19, 314-20, 1916. 



t J. Henderson, The Geology of the Te Kuiti Di.striet, with Special Reference to 

 Coal Prospects, N.Z. Journ. Sci. <& Tech., vol. 1, p. 114, 1918. 



X J. Henderson, Joe. cit. 



