president's address — SECTION c. 103 



The separatiooa of Australia from New Zealand was so complete 

 in Upper Cretaceous time that there is only one species of mollusc 

 (Natica variabilis) yet known to be common to the two areas. 

 (Trechmann 1917). 



As regards the reptilian life of New Zealand in this period, we 

 may note that Dr. C. W. Andrews (fide Woods 1917) has com- 

 pared it with that of the Senonian Niobrara chalk of the United 

 States. 



Thomson's (1918) important studies of the distribution of 

 Recent and Tertiary Brachiopods in the Southern Hemisphere 

 carry us a stage further forward. He concludes that the two 

 gronps that are represented originated, p.erhaps in Early Cteta- 

 ceous times, on the coast of the residue of Gondwana. Land that 

 then existed, and that they have remained almost entirely re- 

 stricted to this region. They s-pread along the coast line, and 

 apparently developed into diverse colonies in the different portions 

 of the littoral zone, which had been restrictd by the early Creta- 

 ceo'Us orogeny. On each district where the " Miocene " and 

 Recent forms occur, the latter are almost always the diminished 

 remnants of the " Miocene " fauna of that locality, and do not 

 call for — indeed preclude — the occurrence of Pliocene land con- 

 nexions to' explain their distribution. The communication between 

 Antarctica and New Zealand, with migration of the brachiopods, 

 may have occurred as early as in the Cretaceous. The character 

 and distribution of certain Middle Tertiary forms suggest, how- 

 ever, a further intermic ration of forms — various widespread 

 species — at the epoch of maximum lextensicn of the sea over the 

 planed land surfaces, which occurred during the warm climatic 

 period of " Oligccene-Miocene " times in Australia, Antarctica, 

 and South America. At this time also the affinities of the mol- 

 lusca of New Zealand to those of South Ameri'^a-Patasjonia, 

 were marked, as has been shown by Ortmann (1902), Button 

 (1904), and Von Thering (1907), and about this time there may 

 have been an introduction of new forms into the New Zealand 

 area. Thus Thomson (1920) remarks: — " It would be premature 

 to assume that there had been a sudden introduction of new forms 

 into the Awamoan (' Miocene '), although that is the actual sug- 

 gestion of the lists." If this should eventually be confirmed, it 

 may, perhaps, be pointed out that the objection that has been 

 raised to a Tertiary land connexion of New Zealand and the An- 

 tarctic with South America, namely, the absence from New Zea- 

 land of the vertebrates, especially mammals, such as occurred 

 in Australia may perhaps be explained by the fact (realize:! fully 

 only during the last few years) that at the time of the supposed 

 introduction of littoral mollusca. New Zealand had become merely 

 a few small islands, separated by an epicontinental sea, by which 

 the entry of t&rrestial vertebrates might be debarred. The study 



