70 president's address — SECIION c. 



some places contain Cretaceous fossils {Inoreramus being particu- 

 larly abundant), but may pass down into Jurassic beds. In most 

 cases they are strongly folded, and more or less faulted. Much 

 work will be required, however, before the relationships of the 

 higher members of the Hokonui series is satisfactorily deter- 

 mined. 



The results of Dr. Arber's palseobotanical studies give a 

 general support of these stratigraphical conclusions, though on ac- 

 count of the poverty of the flora, and somewhat unfavorable con- 

 ditions for its preservation, exact coincidence could not be ex- 

 pected. Moreover, according to Dr. Arber, it is not yet pos- 

 sible to distinguish with certainty between late Triassic and early 

 Jurassic floras. The greater part of New Zealand in the Triassic 

 and Jurassic periods was probably a wide continental shelf con- 

 stantly built out on a subsiding area. When such movement was 

 temporarily checked and lagoons or dry land replaced the shalloiw 

 sea, a scanty flora migrated on to this from the adjacent con- 

 tinental land mass which perhaps lay to- the west and south-west. 

 So far as is yet known there are only a quarter of the number 

 of species noted in the Australian terrestrial Mesozoic rocks 

 (Benson, 1919). The oldest Mesozoic plants are those of Mount 

 Potts, in Canterbury, which Arber considers to be probably 

 Rhaetic. According to Park (1904), they underlie the Kaihiku 

 (Ladino-Carnic) beds, though McKay is uncertain of this (1878, 

 pp. 92 and 95). They contain Thinnfeldia odontopteroides, T. 

 lancifolia, and Clndnphlehu anfitrnlis, together with LingiiifoUuni 

 lillieanvm, the form long thought to be Gloxsopferis. A rather 

 similar flora occurs in the Clent Hills. Small floras dubiously re- 

 ferred to the Rhaetic or early Jurassic, and otners placed with 

 more confidence in the Lower Jurassic, have oeen described from 

 strata in the southern flanks of the Hokonui Hills, formerly 

 grouped within the Catlins and Flag Hill series. A similar as- 

 semblage occurs in the Malvern Hills, west of Christchurch. 

 Taeniopteris (daintreei) spatvia, Cladophlehis, Coniopteris, and 

 cycads occur in these. The well-known fossil foTest at Waikawa, 

 east of Invercargill, in which petrified coniferous trunks are fre- 

 quent, has long been classed in the Mataura Series; at the flora 

 of these Arber has considered as Middle Jurassic. With these 

 also occurred, in all probability, the steins ox Osmundites, de- 

 scribed biv Kidstcn and Gwynne Vaughan (1907), and also' by 

 Sinnott (1914). Of special interest is Arber's recognition that 

 the plant beds of the Waikato Heads near Auckland, the highest 

 portion of the Hokonui system, is of Neocomian Age, and contains 

 two angiosperms, one allied to the modern figs. " This flora is 

 particularly interesting as being probably one of the oldest of the 

 known Neophytic floras." * — (Arber, 1917.) 



• Angiosperms have since been found in rooks of about the same age in Queensland (Walkom, 

 1919). 



