336 KEPORTS OF RESEARCH COMMITTEES. 



L. Cockayne* has pointed cut the large areas oi coastal sand- 

 dunes, totalling about 500 square miles, in various parts O'f New 

 Zealand, but particularly in the provincial districts of Auckland 

 and Wellington, the maximum width of the dune belt being seven 

 miles on the western coast of Wellington., He has also^ discussed 

 fully the building and modification of dunes by wind. Continuous 

 dune-ridges are rare, and the dunes are very irregular in form 

 owing to the formation of wind charinels between portions that 

 are fixed by vegetation. "Sand plains" in areas formerly dune- 

 ( overed are described, from which the whole of the sand down to 

 water-level has been blown away. In general, a dune complex 

 consists of the various types of dunes, accumulating, fixed, and in 

 coarse of destruction, with sand plains, and with ponds, lakes, 

 and swamps caused by the blocking of streams. Prior to the 

 arrival of man the dunes must have been much more completely 

 fixed than at present, and interference with the vegetation has 

 caused the dunes in many places to revert to the " wandering " 

 condition. 



C. A. Cottonf has employed physiographic criteria in the main 

 to show that the relief of New Zealand is almost entirely of tec- 

 tonic crigin, and that the New Zealand region may be described 

 as a " concourse of earth-blocks," the higher of which lie along the 

 north-east and south-west axis of the land-mass. This late period 

 (if mountain-building, which is perhaps post -Pliocene, has been 

 termed the Kaiko^ura orogeny. 



The blocks or tectonic units, which determine the positions of 

 mountains and valleys, are frequently bounded by fault-scarps. 

 They are not, however, simply blocks bounded by normal faults 

 tliat might be ascribed tc tension ; for there is much evidence of 

 compression in the presence both of thrust-faults of large displace- 

 ment and of the rather close folding which is found in many places 

 in the strata of Tertiary age forming the upper parts of the 

 blocks. 



Geclcgical evidence of faulting is often found in the apjiositioai 

 of Tertiary and older rocks at the bases of the scarps. 



* L. Cockayne, Report on the Dune areas of New Zealand, N.Z. Pari. Paper C. — 13 (Depart- 

 ment of Lands), 1911. 



t C. A. Cotton, Notes on Wellington Physiosraphy, Trans. N.Z. Inst., vol. 44. pp. 245-65 

 1912. Recent and Sub-recent Movements of Uplift and of Subsidence near Wellington, New 

 Zealand, Scottish GeoqrapJiical Magazine, vol. 28, pp. 306-12, 1912. The Physiography of the 

 Middle Clarence Valley, New Zealand, Geoiiraph>ia' .Joiimat, vol. 42, pp. 225-46, 1913. The 

 Tuamarina Valley: A Note on the Quaternary History of the Marlborough Sounds District, 

 Trans. N.Z. Inst., vol. 45, pp. 316-22, 1913. Supplemontary Notes on Wellington Physiograph> , 

 Trans. N.Z. Inst., vol. 46, pp. 294-98, 1914. Fault Coasts in New Zealand, Geographical Revintr, 

 vol. 1, pp. 20-47, 1916. The Structure and Later Geological History of New Zealand, Geological 

 Magazine, decade 6. vol. 3, pp. 243-49, 314-20, 1916. Block Mountains and a " Fossil " Denu- 

 dation Plain in Northern Nelson, Trans. N.Z. Inst, vol., 48, pp. 59-75, 1916. Block Mountains in 

 New Zealand, American Journal of Science, vol. 44, pp. 249-93, 1917. The Fossil Plains of North 

 Otago, Trans. N.Z. Inst., vol. 49, pp 429-32, 1917. River Terraces in New Zealand, N.Z. 

 ■lournal of Science and Technology, vol. 1, pp. 145-52, 1918. The Outline of New Zealand, Geo- 

 graphical Review, vol. 6, pp. 320-40, 1918. Mountains, N.Z. .Journal of Science and Technologu, 

 vol. 1, pp. 320-40, 1918. Problems presented by the Notocene Beds of Central Otago, N.Z. 

 ■Journal of Science and Technology, vol. 2, pp. 69-72, 1919. Rough Ridge, Otago, and its Splin- 

 tered Fault-scarp, Trans. N.Z. Inst., vol. 51, pp. 282-85, 1919. 



