president's address — SECTION c. 99 



also. The dominant rock is blue marly clay, becoming more 

 or less sandy in places. In the lower portion of the series they 

 are more varied, coarse-grained sands and even pebbly beds are 

 present; false-bedding due to tidal scour may be observed, and a 

 concretionary, shoal-water, arenaceous limestone occurs. Note- 

 worthy is the evidence of two land-surfaces indicated by "a, 

 stratum of beach-worn pebbles, a carbonaceous stratum with roots 

 penetrating the clay beneath, and a numb:r of molluscan bores 

 penetrating it." Tlie thickness of rocks studied is approximately 

 3,560 feet, and they are more or less fossiliferous throughout. 

 Collections, each typical of a thickness of about 500 feet, were 

 made at intervals of approximately 1,000 feet thickness of strata. 

 The lowest beds contained 72 forms (Gl per cent, of Recent 

 forms), the neixt group of beds contain 84 forms (76 per cent. 

 Recent). In these were found bones of two* species of moa. Above 

 these a series of 82 forms was obtained containing 90 per cent, of 

 Recent species whilei the highest fauna of the whole formation 

 occurring at the mouth of the Wanganui River yielded 93 per 

 cant of Recent forms out of a total of 181 species, " Pleistocene" 

 beds lie unconformably upon these. With this wonderful succes- 

 sion is concluded the record of the marine deposits of the Notocene 

 period. 



Terrestrial Notocene Deposits. 



While the early geologists supported the view that the marine . 

 rocks described above were deposited in embajrments roughly 

 corresponding in form to the present areas of Tertiary rocks, 

 modern research is tending to con'firm McKay's view that the 

 scattered areas are mostly inf aulted residuals of a sheet of almost 

 continuo'Us marine rocks preserved from erosion by being faulted 

 down into the harder under-mass. Only in Central Otago, is 

 there evidence of a persistent land surface, and here the meta- 

 morphism of the older rocks appears to^ indicate that a gieat 

 mountain range was reared in late Mesozoic times, which, however, 

 was reduced to a peneplain in thei succeeding epoch, when a very 

 widespread series of terrestrial deposits were laid down. These 

 were studied in detail by Hutton (1875), McKay (1883, 1884), and 

 Park (1906-8-9). They consist in part of possibly lacustrine de- 

 posits (Morgan 1920), and of fluviatile brds (Cotton 1919), which 

 may h^ grouped into twoi unconformable series, indicating that 

 here also crust-warping occurred during the Tertiary period. The 

 basement beds of auriferous cements in this scries in Eastern 

 Otago have been considered to be of " Eocene" age by Marshall 

 (1918') who' classed with them a series of conglomeratic rocks near 

 Dunedin ("the Taieri Moraine"), the supposed glacial origin of 

 which had been a long-rtanding difficulty in the interpretati n of 

 tlie geological history of Otago. In relegating these to a fluviatile 

 origin, Marshall is supported by Trechmann (1918) and Professor 



