Cotton. — Warped Land-surface at Port Nicholson. 143 



uplift would be indicated by convergence of the beach-ridges. While 

 aneroid observations do not indicate tilting (Aston, 1912), spirit-levelling 

 of the 40 ft. and 60 ft. beaches might show a small amount of the latter 

 kind. The higher beaches are largely smothered by fans, and correlation 

 of isolated • parts is somewhat uncertain. So these would be less suitable 

 for testing by precise levelling. 



The writer's observations, though his investigation of the Turakirae 

 coastal plain has been very incomplete, have convinced him that the 

 tapering-away of the plain at each end is due not to tilting, but to the 

 rocky platform being cut away by marine erosion as the land rose. At the 

 north-eastern end the beaches are smothered by fans, which must conceal 

 also the cliffed margin of the higher part of the plain. The lower part of the 

 plain continues some distance farther as a narrow bench 20 ft. above the 

 sea, with a cliffed margin. 



Towards the western end of the plain the higher beaches are smothered 

 in a similar way by fans, but beyond these there is at the western side 

 of the mouth of the Wainui-o-mata a small cliffed remnant of a beach- 

 covered bench which appears to be at exactly the height of the rear of the. 

 plain at Cape Turakirae. The platform which bears the 60 ft. beach-ridge 

 is also distinct on both sides of the mouth of the Wainui-o-mata ; but 

 farther west there is no further trace of the coastal plain, though in Fitzroy 

 Bay there is a modern storm-beach ridge 10 ft. to 12 ft. above mean sea- 

 level, and also a raised beach-ridge, presumably the pre-1855 beach, 10 ft. 

 higher. 



The discontinuity of the Turakirae coastal plain remains an unsolved 

 problem. There is no trace of it around the comparatively sheltered inner 

 shores of Port Nicholson, or, indeed, anywhere west of Baring Head. If 

 it has been exposed by differential uplift, or its continuation resubmerged 

 by differential subsidence, no fault-scarp boundary between the differently- 

 moving blocks has been traced, and if this boundary is a warped surface 

 the warped part of the Turakirae coastal plain must have been cut away 

 by marine erosion. It is clear, however, that the even uplift of the 

 Turakirae coastal plain took place later than the warping described in 

 the body of this paper. 



List of Papers referred to. 



Adkin, G. L., 1919. Further Notes on the Horowhenua Coastal Plain and the 



Associated Physiographic Features. Trans. N.Z. Inst., vol. 51, pp. 108-18. 

 Aston, B. C, 1912. The Raised Beaches of Cape Turakirae, Trans. N.Z. Inst., vol. 44, 



pp. 208-13. 

 Bell, J. M., 1910. The Physiography of Wellington Harbour, Trails. N.Z. Inst., 



vol. 42, pp. 534^0. 

 Broadgate, F. K., 1916. The " Red Rocks " and Associated Beds of Wellington 



Peninsula, Trans. N.Z. Inst., vol. 48, pp. 76-86. 

 Cotton, C. A., 1912. Notes on Wellington Phvsiography, Trans. N.Z. Inst., vol. 44, 



pp. 245-65. 



1914. Supplementary Notes on Wellington Physiography, Trans. N.Z. Inst.. 



vol. 46, pp. 294-98. 



1916. The Structure and Later Geological History of New Zealand, Geol. Mag., 



dec. vi, vol. 3, pp. 243-49, 314-20. 



1916a. Fault Coasts in New Zealand, Geogr. Rev., vol. 1, pp. 20-47. 



1916b. Block Mountains and a " Fossil " Denudation Plain in Northern Nelson, 



Trans. N.Z. Inst., vol. 48, pp. 59-75. 



1918. The Outline of New Zealand. Geogr. Rev., vol. 6, pp. 320-40. 



1921. For how long will Wellington escape Destruction by Earthquake ? 



N.Z. Journ. Set. dk Tech., vol. 3, pp. 229-31. 

 Lyell, C, 1868. Principles of Geology, 10th ed., vol. 2, p. 82. 



