2 Transactions. 



of discovering hidden coalfields may be mentioned. The geologist's esti- 

 mates of the probability of buried coal and of its depth in a district where 

 only younger Tertiary rocks are exposed at the surface will be strongly 

 influenced by his preconceived views of what to the layman appear to be 

 purely scientific and therefore economically immaterial questions. Pro- 

 gress in stratigraphical geology has till recently been greatly impeded by 

 the lack of detailed surveys and of reliable .determinations of fossils. 

 Advance in these matters is now being made, but for some years to come 

 the imperfect data available will afford scope for rival hypotheses such as 

 those that were so keenly debated in past years. 



The object of the present paper is to review the stratigraphical evidence 

 that has been advanced for unconformities in the succession of rocks em- 

 braced by Hector's Cretaceo-tertiary, Eocene, and Miocene formations, 

 or, alternately, by Hutton's Waipara, Oamaru, and Pareora systems. A 

 perusal of the paper by Marshall, Speight, and Cotton already mentioned 

 will give the reader a good idea of the confusion introduced into New 

 Zealand literature by the uncoordinated efforts of independent observers, 

 each of whom was endeavouring to add to the sum of human knowledge. 

 On this occasion the writer, taking a somewhat different standpoint from 

 that of Marshall and his colleagues, hopes to be able to clear a portion of 

 the field. In order to do so the various localities where stratigraphical 

 breaks have been suspected will be separately discussed. Most attention will 

 be given to an unconformity that seems to be invariably present at the 

 base of the strata included in Hutton's Oamaru System. The palaeonto- 

 logical evidence for this may here be summarized by the statement that 

 it is nowhere inconsistent with this view, and, as a rule, strongly supports it. 



The following classification of the Cretaceous and Tertiary formations 

 roughly represents the writer's views : — 



Age. Extent. 



Pliocene . . . . . . Ormond beds, Petane Series, upper part 



of Wanganui System, &c. 

 Local unconformities . . (Gisborne district, Reefton district.) 



Upper Miocene . . . . Waitemata Series ; Pareora System of 



Hutton ; Eocene and Miocene of Hector 



and McKay. 

 Probable local unconformities (Reefton district, North Canterbury, <fec.) 

 Middle and Lower Miocene . . Papakura Series, &c. ; Oamaru System 



of Hutton ; Cretaceo-tertiary System of 



Hector, in part. 

 Unconformity . . . . (Not fully proved in all districts.) 



Eocene . . . . . . Bituminous-coal measures on west coast 



of South Island ; Cretaceo-tertiary Sys- 

 tem, in part. 

 Unconformity (?). 



Cretaceous (with possibly some Waipara System of Hutton ; Cretaceo- 

 early Tertiary strata) . . tertiary System, in part. 



Local unconformities such as those shown in the above table between 

 Middle and Upper Miocene, and again between Miocene and Pliocene, 

 almost certainly do not belong only to the horizons mentioned. It is 

 highly probable that detailed field-work will demonstrate that from the 

 Middle Miocene to the Pleistocene differential movements in some part 



