64 Transactions. 



The marine sand and gravel forming the low hill in the small valley near 

 the Patea brickworks presumably represent a rewash of the Hawera beds 

 deposited during a brief period of depression. Probably there were other 

 occasional minor oscillations during the last uplift, but there is no evidence 

 of prolonged periods of standstill. 



The marine planation of a wide belt of the Wanganuian beds is a 

 remarkable fact, which has a bearing on the geological history of other 

 parts of New Zealand. Had the upward and downward movements of 

 the Wanganui beds been uniform, the eroded surface would have been 

 almost or quite parallel to the bedding-planes, more especially if there had 

 been a hard stratum of, say, limestone just below the level of the sea at 

 the time of greatest depression. In that case the Hawera series would 

 have been deposited on the Wanganuian without any visible unconformity, 

 and a contact similar to that of the Amuri limestone and the Weka Pass 

 stone in North Canterbury would have resulted. 



According to Thompson's view of the origin of the Hawera beds, their 

 upper surface must be wave-planed ; and this statement holds good in the 

 main, even if the present writer's hypothesis of their deposition during a 

 negative movement of the strand be correct. The planation is not confined 

 to the area between Hawera and Turakina, but may be traced north- 

 westward beyond Cape Egmont, and southward, with some interruption, 

 to Otaki, and finally to the immediate neighbourhood of Wellington. The 

 gently sloping lowland at the foot of Mount Egmont extending from 

 Hawera to Cape Egmont and thence northward to the Kaitake Range 

 has been wave-smoothed in the late Pleistocene. In places numerous 

 small conical hills of volcanic origin, formed almost in Recent times, stud 

 its surface, but evidence of planation by the sea remains. In the Shannon 

 district, and elsewhere south of the Manawatu River, aeolian sandstones, 

 probably younger than Castlecliffian, appear to have been planed by wave- 

 action, an interpretation of their topography partly supported by Adkin's 

 account (9 ; see also his paper of 1911), but opposed to Cotton's views (8). 

 At present only small portions of the Wanganui coastal plain have been 

 examined in detail by geologists. These examinations have been made 

 independently by various workers, at various times, and for various objects. 

 Some divergence of opinion is therefore to be expected, but this will 

 doubtless be eliminated when the results of detailed surveys over wide 

 areas are available. 



Literature. 



1. R. Pharazyn, Remarks on the Coast-line between Kai Iwi and Waitotara, on the 



West Coast of the Province of Wellington, Trans. N.Z. Inst., vol. 2, pp. 158-60, 

 1870. 



2. John Buchanan, On the Wanganui Beds (Upper Tertiaries), ibid., pp. 163-66. 



3. F. W. HrTTON. The Wanganui System, Trans. N.Z. Inst., vol. 18, pp. 336-67, 



1886. 



4. James Park. On the Geologv of the Western Part of Wellington Provincial District 



and Part of Taranaki, Rep. Oeol, Explor. during 1886-87, No. 18, pp. 24-73., 1887. 



5. Henry Hill, Artesian Wells at Wanganui, New Zealand, Trans. N.Z. Inst., vol. 25, 



pp. 348-50, 1893. 

 C>. W. Gibson, Patea Tronsand, Ninth Ann. Rep. N.Z. Oeol. Surr. (part of Pari. 

 Paper C.-2), pp. 102-3, 1915. 



7. J. A. Thomson, The Hawera Series, or the So-called "Drift Formation" of Hawera, 



Trans. N.Z. Inst., vol. 49, pp. 414-17. 1917. 



8. C. A. Cotton, The Geomorphology of the Coastal District of South-western 



Wellington, Trans. N.Z. Inst., vol. 50, pp. 212-22, 1918. 



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



Physiographic Features, Trans. N.Z. Inst., vol. 51, pp. 108-18, 1919. 

 10. P Marshall and R. Murdoch, The T-rtiarv Rocks near Wanganui, Trans. 

 N.Z. Inst., vol. 52, pp. 115-28, 1920. 



