

iuJ t I S R A R Y 1 :33 



TRANSACTION sV:^- 



OF THE 



NEW ZEALAND INSTITUTE, 



1915. 



Art. Li — -^Recards of Umonformities from Late Cretaceous to Early 



Miocene in New Zealand. 



By P. Gr. Morgan, M.A., F.G.S., Director of the Geological Survey of 



New Zealand. 



[Read before the Wellington Philosophical Society, 29th September, 1915.] 



Introduction. 



Various geologists, notably Hutton, have striven, mainly on palaeonto- 

 logical grounds, to show that unconformity exists between the Cretaceous 

 and Tertiary rocks of New Zealand. On the other hand, Hector and 

 the various workers associated with him as members of the stafi of the 

 Geological Survey stoutly supported what is commonly known as the 

 Cretaceo-tertiary theory, and consistently denied the existence of any 

 stratigraphical break in the horizon postiilated by Hutton. Being willing, 

 however, to admit unconformities between Cretaceo-tertiary and supposed 

 Eocene strata, and again between the latter and Miocene rocks, in the 

 course of field-work they frequently recorded breaks as present in one or 

 other of these positions. Park, though at one time a supporter, in 1900 

 (34,* p. 350) definitely dissociated himself from the Cretaceo-tertiary 

 hypothesis, and since then, except in minor details, has been in essential 

 agreement with Hutton. In 1911 Marshall, Speight, and Cotton, in a joint 

 paper (47), expressed their opinion that the Cretaceous and Tertiary rocks 

 of New Zealand form a single series, unbroken by any marked uncon- 

 formity. Their views must therefore be regarded as an extension of the 

 old Cretaceo-tertiary hypothesis, the main point of difference being that 

 the two unconformities supposed by Hector and his colleagues to exist in 

 the Lower and Middle Tertiary sequence were eliminated. 



Since the Cretaceous and Tertiary rocks of New Zealand contain 

 practically all the workable coal, the interpretation of their stratigraphical 

 relations becomes one of great importance. As an example, the problem 



* This and other numbers similarly enclosed in parentheses refer to the biblio- 

 graphy at the end of this paper. 



1.— Tians. 



