254 Transaction* . 



From the above description and from fig. 6 it will be gathered that 

 the coast-line of the downthrown Port Nicholson block is a normal 

 drowned coast, passing through the normal cycle of littoral erosion 

 which has reached the early mature stage. It is thus in strong con- 

 trast with the coasts of the neighbouring high-standing blocks described 

 in the next paragraph. 



Coast Features. 

 The Cliffs. 



The actual outline of the coast of the high-standing block is the 

 result of marine erosion working back from an earlier coast-line almost 

 certainly bounded by fractures. This seems to be the only view tenable, 

 for the amount of marine erosion necessary to cut back the present 

 coast, with its line of lofty cliffs, from a coast-line of any other form 

 would be enormous, and seems out of the question when a comparison 

 is made with the recently revived condition of the land -drain age. There 

 is no evidence of a slow sinking of the land such as would be required 

 to keep up the activity of wave-action on a receding coast. The 

 depths of hundreds of fathoms recorded within a very few miles of the 

 southern coast indicate that the block to the south has sunk, and the 

 closeness of the hundred-fathoms line to the western coast indicates sub- 

 sidence in that direction. 



The hypothesis of a fracture-bound coast gains further support from 

 the relation of the coast-line to stream-courses on the land-surface. 

 The Silver Stream (see fig. 2) rises at a height of 1,000 ft. only three- 

 quarters of a mile from the southern coast, and flows northward. The 

 western coast also cuts in along a north-easterly line, making an angle 

 with both the strike of the rocks and the stream-courses. The Ohariu 

 Stream, on the north-west, like the Silver Stream on the south, rises 

 almost on the coast, and flows inland. 



Cook Strait, which bounds the Wellington Peninsula on the west and 

 south, has been generally regarded as the result of faulting since the time 

 of Hochstetter, whose views were followed by Hutton and more recently 

 by Park. Hochstetter's early view* was that one island had been thrust 

 laterally past the other — that is, that the movement was of the nature 

 of a " flaw."' As has been pointed out by Suess, however, Hochstetter's 

 later viewf was that Cook Strait owed its origin simply to the subsidence 

 of a mountain block or blocks, and he was aware that the continuation 

 of the North Island ranges is to be found on the same line of strike in 

 the Kaikoura Mountains of the South Island. This relation is brought 

 out by Marshall's! maps of physical features of New Zealand. 



The west and south coasts present similar features. The only pro- 

 jecting points are those composed of resistant rock, usually bands that 

 are hardened with interlacing veins of quartz, filling joints. The inter- 

 vening, less resistant rock bands recede as bays of gentle curvature, 

 bounded by imposing cliffs. The larger streams emerge at beach-level, 

 in gorges revived and steepened by the rapid recession of the coast, 



* Lccti iv on the Geology of the Province of Nelson, 1859, reprinted in " Geology 

 of New Zealand" (Auckland. 1864), p. 106; see also Park's " Geology of New Zealand." 

 1910, p. 262. 



t " Reise der ' Novara," " 1864, Geol. vol. 1, p. 2. 



% Loc. cit., pp. 10, 11. 



