PRESIDENT S AUDRESS — SECTION C. 



85 



narrow intermontane strips of younger rocks are but disclocated 

 remnants of more extensive sheets which, at one time, covered 

 nearly all of the area that is now New Zealand. " There can be 

 no doubt that the mountain ranges which resulted from the 

 Meso:oic orogenic movements, had been subjected to erosion 

 throughout a long period, and reduced to at least a moderate re- 

 lief before the deposition of the oldest beds of the covering series 

 . There is certainly overlap in the lower beds, indicating 

 that the eroded surface of the older mass was soniewhat hilly 

 when submergence began " (Cotton). " Elevated land appeared 

 to have existed longest in the north-west, where immense thick- 

 ness3s of heavy conglomerate formed in early Tertiary times, while 

 planation was practically complete on the eastern side of the 

 island " (Speight). In general, the covering strata, with the 

 exception of the basal beds, are anaiine, and of such nature as to 

 indicate that they were accumulated in the open sea, where the 

 supply of sediment was small. Hence, during their deposition, 

 a great part of the site of the present islands of New Zealand was 

 usually submerged, though low islands existed both within 

 and outside the present limits of New Zealand, from whioh detritus 

 was derived. (Cf. Speight, 1915, p. 351.) ihe mo:.t persistent 

 land area was that of Central Otago, the region where the folding 

 had been piled so high as to lead to the production of micaceous 

 schists. Since we cannot discuss the Notocene record by its prob- 

 able time divisions, without assuming premature correlations of 

 strata, we shall instead describe typical districts, wltli but small 

 attempt at correlating the various stages in different areas. We 

 must note, however, that a very useful provisional correlation- 

 table was prepared by Morgan in 1918, and this is brought by him 

 up to date in a valuable note that will be laid before tnis section. 

 Thanks to his courtesy, I am permitted to add this, and other 

 tables as an appendix to this address. 



Fig. 6. Diagram illustrating the type of structure and sculptme in the Middle Clarence 

 Vallry. (After Cotton, 1914.) 



Mudstone — Clarentian (Albian Beds). limestone — (Panian ?) Amuri Limestone. 

 Marl — " The Grey Marl." Conglomerate — "The Great Marlborough Conglomerate." 



