82 president's address — section c. 



Before summarizing the present knowledge, two points must be 

 stressed. The hypothesis which held that all the limestones were 

 of the same age, and that no' unconformities or disconformities 

 existed, had to recognise that sometimes a fauna of a Cretaceous 

 aspect, and sometimes one of an Oligocene aspect lay immediately 

 below the l:me:tcne. This necessitated an explanation oi: the 

 absence of a characteristic Eocene fauna, and the rapid change of 

 lif:i-forms ; as such was suggested the isolation cf New Zealand, 

 the lingering here of archaic forms, and the alleged abnormally 

 slow rate of deposition of some of the sediments. The recognition 

 of the clo'se relation of the Cretaceous faunas of New Zealand to 

 those of other lands, which we owe to Woods, Trechmann, and 

 Wiljkens; the recent proof of the existence of an extensive Eocene 

 fauna in certain regions, which is due to Marshall; and the 

 evidence of variation in age between the limestones, urged 

 by Thomson and others, reimoves these difficulties in a great 

 measure. Moreover, the local absence from between Cretaceous 

 rocks and those oi (say) Oligocene aspect, of an Eocene 

 fauna such as occurs in adjacent regions, without the 

 intervention of a great thickness of unfossiliferous beds, should 

 be at least suggestive of the existence here of a discon- 

 formit-y. Again, though the adoption of the modified Lyellian 

 m°ithod of determining the relative age of Nctccene beds will pro- 

 bably be of great service in New Zealand, it must be recognised 

 that the diastrophic histories of New Zea'and and Europe have 

 been so different, that it would be unlikely that the rate of evolu- 

 tion of new species, and the elimination of old would be exactly 

 the same here as in Europe, and that, therefore, if the familiar 

 terms. Eocene, Miocene, &c., are ured at all here, it is toi indicate 

 the relative ages of groups of beds, but not specifically their age in 

 comparison with the European time-scale, f Indead, it might be 

 most correct to abandon for the present the employment of these 

 ol;! terms, though they are so useful in making clear the record to 

 those unfamiliar with local terminology that they have been re- 

 tained in this address in the above generalized sense, but the 

 convention is adopted of placing tlie terms so used between inverted 

 commas. For minor stage-names a nomenclature based on local 

 namos has been suggested, and is given in Table IV. 



The character of the land surface upon which the Notocene beds 

 were deposited has also been considered more carefully" than 

 formerly. Early observers, especially Hutton (1900), thought the 

 embayed outlines of the present areas cf Notocene rocks indioted 

 the outlires of the regions of deposition of these in narrow tro'^-ghs 

 among the mountains, and this view was accepted by Suess 

 (1906^11. p. 148). Modern workers (e.g., Cotton, 1913, 1916, and 

 Speisht. 1915, p. 153), confirm MoKav's view (1892) that these 



t R'fe-en'e should he made to Ortmann's (1902. pp. 288-300) criticism of the use of the 

 Lyellian method, and the alternative adoijted by him. 



