•Marshall, Spei(;h'1', Cotton. — Yoni/;/er nock-t<('rirs of N.Z. 381 



This series, of course, varies considerably in different localities. Some 

 members may be quite omitted, while others are relatively thick. In general, 

 it is thought that the following statement represents, without attention 

 to purely local features, the variations that are found in different localities. 



In North Canterbury practically the whole series is present. In Otago 

 it is luiusual to find any beds higher in the series than the limestone. In 

 AVestland and at Cape Farewell and Shag Point the basal conglomerate 

 is of great thickness — 7,000 ft. in the first case — and it contains important 

 seams of coal. 



In the North Island, but more particularly iu its southern portions, 

 there is an immense development of the grey marls, w^hich in the Wanganui 

 country are perhaps 2,000 ft. thick. The greensands are highly variable 

 in thickness, and are often absent ; they have a particularly large develop- 

 ment in North Canterbury. The limestone is fairly general, and the most 

 constant member of the series, but landwards always becomes somewhat 

 sandy, and even passes into pure cjuartz sand where it is marginal to the 

 old land. 



As will be more fully mentioned later, the fossils contained in the rocks 

 at the base of the series are wholly different from those at the. top ; in fact, 

 the lowest rocks, in some localities at least, contain Mesozoic forms, and 

 have been referred by all observers to the Cretaceous period. On the other 

 hand, there is a high percentage of Recent species in the highest rocks, and 

 they are classed as Upper Miocene or Pliocene on all hands. 



It appears to have been the general belief of those geologists who have 

 examined these rocks that a rock-series showing evidence of such great 

 difference in age in its lowest and highest members could not have been 

 deposited in a uniform stratigraphical sequence as a single formation. It 

 has therefore been thought necessary by all authorities to refer different 

 portions of the rock-sequence to different geological systems the members 

 of which are supposed to be separated by unconformities. Unfortmiately, 

 while there has been an agreement in principle, there has been a marked 

 divergence in practice, and no two authorities have placed the unconformities 

 in the same places. This is the more remarkable as in nearly all localities 

 where the rocks occur there is a fine exposure of natural sections in w^hich 

 the rock-series are displayed free from all obscurity, and in most cases with 

 nothing but folding of a most simple description. 



The great variety of opinion in regard to this matter is shown in the 

 following summary of the classifications adopted by those geologists who 

 have published comprehensive works dealing with the geology of the whole 

 or of large portions of the Dominion. 



II. Classifications employed. 



(a.) Hochstetter {" Reise der ' Novara ' : Geologic," vol. 1, p. 39. Wien, 



1864). 



Kainozoic Series. — (1.) Older Tertiary System: (a) Brown coals, 

 Lower — Coalfields of Drury, Waikato, North Auckland, Nelson, Otago ; 

 (b) Marine series, Upper — Waitemata, Kawhia, and Aotea, Motupipi 

 (Nelson), Aorere (Nelson), gold-bearing conglomerate (Aorere), white and 

 yellow calcareous sands and greensands with limestone, Oamaru, Green 

 Island, Shag Valley. (2.) Younger Tertiary : Cape Rodney, Hawke's 

 Bay, Wanganui River, Nelson cliffs, blue clay of Awatere, Waitaki, Moe- 

 raki. 



