392 Transactions. 



with the greywacke. There is also no sign of dislocation in the discordance 

 of the grades of the streams which would cross such a line : perhaps this 

 point is of no great importance. I am therefore of the opinion that the 

 determining cause of the formation of such great hollows as Lyttelton 

 and Akaroa Harbours is prolonged water erosion and not paroxysmal 

 explosions, although an explosion of moderate intensity or the breaching 

 of the cone by a lava-flow may have initially determined the directions of 

 the streams which established themselves on the surface of the volcano. 



The landscape features of these two harbours are reproduced almost 

 exactly in the case of Carnley Harbour, in the Auckland Islands, the com- 

 parison with Akaroa being especially striking,* except that Carnley is on a 

 much larger scale, and instead of having one peninsula it has three large 

 peninsulas forming long trailing spurs directed towards its interior. The 

 agreement as to nature of the lavas, arrangement of the flows, height of the 

 encircling hills, form of the internal and external slopes, and the shape of 

 the great cavity suggest a similar origin and a similar geological history. 

 No doubt the hollow was formed primarily by a moderate explosion or by 

 breaching of the cone, and was enlarged subsequently by stream erosion 

 and a glaciation of moderate intensity — the latter absent in the case of Akaroa 

 — at a time when the land was higher. The enlargement of the cavity by 

 erosive agents and the removal of the periphery of the mountain by the 

 action of the sea have resulted in the partial break of the walls at one place 

 on the western side and in their complete breakdown in another, and through 

 the gap fierce tides and heavy waves pour into the western portion of the basin. 

 The proper entrance is placed at the east, being exactly similar in form and 

 cross-section to that of Akaroa and Lyttelton, with a distinctly fiord-like 

 character, a result perhaps due partly to glacier action, but certainly 

 attributable in great part to the action of water as described previously. 



Art. XXVII. — The Relationship of the Upper Cretaceous and Lower 

 Cainozoie Formations of Neiv Zealand. 



By Professor James Park, F.G.S., Otago University, Dunedin. 



[Read before the Otago Institute, 5th December. 1916; received by Editors, 30th December, 

 1916 ; issued separately, 20th November, 1017.] 



In vol. 48 (1915) of the Transactions of the New Zealand Institute there 

 appear papers by Mr. P. G. Morgan, Dr. J. Allan Thomson, and Dr. 

 Marshall dealing mainly with the relationship of the Lower Cainozoie marine 

 strata of New Zealand to the Upper Cretaceous. In each of these papers 

 my own views as to the so-called Cretaceo-Tertiary succession, and those 

 of other New Zealand geologists, are discussed at considerable length. Of 

 an admittedly complex problem, rendered all the more puzzling to outside 

 geologists by the great diversity of opinion expressed at various times by 

 many writers, Morgan's paper]" embodies, to my mind, the most lucid and 

 comprehensive exposition that has so far been placed on record. He recog- 

 nizes the Miocene age of the uppermost beds at Waipara and Weka Pass, 



*R. Speight, Physiography and Geology of the Auckland. Bounty, and Antipodes 

 Islands, Subantarctic Islands of New Zealand, 1909, p. 708. 



f P. G. Morgan, Records of Unconformities from Late Cretaceous to Early Miocene 

 in New Zealand, Trans. N.Z. Inst., vol. 48, pp. 1-18, 1916. 



