168 Transactions. 



(5.) The greensands at Wharekuri probably represent a slightly higher 

 horizon than the Bortonian of Park, and from the evidence at present 

 available they are probably the equivalents of the Waiarekan tufis, yet 

 the latter are practically unfossiliferous. 



(6.) Vofcanic rocks, as shown in a previous paper {Trans. N.Z. Inst., 

 vol. 50, pp. 106-17, 1918), occur in the Maruwenua district : they may be 

 either lava-flows or sills — the evidence in the small exposure observed was 

 neutral. These volcanic rocks, however, extend towards Tokarahi, and 

 are interbedded with the greensands. If they are Waiarekan it would fix 

 the age of the greensands overlying Park's Bortonian. 



(7.) The Tertiary rocks of the Waitaki Valley above Duntroon occupy 

 a tectonic depression. McKay has recorded Tertiary rocks from the Haka- 

 taramea Valley, which is also undoubtedly a tectonic depression. As 

 post-Awamoan gravels have been involved in the differential movements 

 in many localities in the Waitaki and Waihao Valleys, these " fiord -like 

 depressions " manifestly did not exist in Tertiary or pre-Tertiary times, 

 and the evidence to be gathered in noi"th-east Otago points to the con- 

 clusion that the Tertiary rocks once formed a continuous cover on the 

 denuded surface of the pre-Notocene oldermass. The mountain-building 

 period of central and north-east Otago was post-Awamoan. < 



Bibliography. 



Cotton, C. A., 1917a. Block Mountains in New Zealand, Am. Journ. Sci., vol. 44, 

 pp. 249-93. 



1917b. The Fossil Plains of North Otago, Trans. N.Z. Inst., vol. 49, pp. 429-32. 



Hamilton, A., 1904. Notes on a Small Collection of Fossils from Wharekuri, Trans. 



N.Z. Inst., vol. 36, pp. 465-67. 



Hkctor, J., 1882. Waitaki Valley and Alps of North Otago, N.Z. Geol. Surv. Prog. 

 Rep., 1881, pp. xxi-xxxii. 



Htjtton, F. W., 1885 On the Correlations of the "Curiosity Shop Bed" in Canter- 

 bury, N.Z., Quart. Journ. Geol. Soc, vol. 41, pp. 547-64. 



McKay, A., 1882a. On the Waitaki Valley and Parts of Vincent and Lake Counties, 

 Bep. Geol. Explor. during 1881, pp. 56-92. 



1882b. On the Younger Deposits of the Wharekuri Basin and the Lower Waitaki 



Valley, Rep. Geol. Explor. during 1881, pp. 98-105. 

 Marshall, P., 1915. Cainozoic Fossils from Oamaru, Trans. N.Z. Inst., vol. 47, 



pp. 377-87. 

 Park, J., 1904. On the Discovery of Permo-Carboniferous Rocks at Mount Mary, 



North Otago, Trans. N.Z. Inst., vol. 36, pp. 447-53. 

 1905. On the Marine Tertiaries of Otago and South Canterbury, Trans. N.Z. 



Inst., vol. 37, pp. 489-551. 



1918. The Geology of the Oamaru District, North Otago, N.Z. Geol. Surv. Bull. 



No. 20 (n.s.), pp. 1-124. 

 Thomson, J. A., 1915. Classification and Correlation of the Tertiary Rocks, 8th Ann. 

 Bep. N.Z. Geol Surv., pp. 123-24. 



