Thomson. — Diastrophic Correlation and Districts in the Xotocene. 413 



Migration in brachiopods is conditional on continuous areas of sea- 

 bottom above the 1,000-fathom line. The deep seas are barriers as effective 

 as land barriers. With molluscs, however, this is not the case. The free- 

 swimming larvae can cross the deep oceans in the surface currents, and 

 distribution is controlled by the direction of the currents. A land connec- 

 tion with Australia or the Antarctic is not, therefore, essential for immigra- 

 tion of molluscs, but only such a change in the distribution of land and sea 

 as would cause new currents to strike these shores. 



VIII. List of Papers cited. 

 Chamberlin, T. C. 1909. Diastrophism the Ultimate Basis of Correlation, 



Journ. Geo!., vol. 17, pp. 685-93. 

 Chamberlin, T. C, and Salisbury, R. D., 1909. Geology : Processes and 



their Results, 2nd ed. (ref. to p. 2). 

 Cotton, C. A., 1913. The Physiography of the Middle Clarence Valley, 



New Zealand, Geogr. Journ., vol. 42, pp. 93-115. 

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



Geol. Mag., dec. 6, vol. 3, pp. 243-49, 314-20. 

 Hector, J., 1864. Geological Survey Department, Votes and Proc, Prov. 



Council of Otago, N.Z., Sess. xviii, Departmental Reports, No. xi, 



pp. 85-132 (ref. to p. 92). 

 Hutton, F. W., 1887. On the Geology of the Country between Oamaru 



and Moeraki, Trans. N.Z. Inst., vol. 19, pp. 415-30. 

 Marshall, P., 1916 (No. 1). The Younger Limestones of New Zealand, 



Trans. N.Z. Inst., vol. 48, pp. 87-99. 

 — — 1916 (No. 2). Relations between Cretaceous and Tertiary Rocks, 



Trans. N.Z. Inst., vol. 48, pp. 100-19. 

 Marshall, P., Speight, R., and Cotton, C. A., 1911. The Younger Rock- 

 series of New Zealand, Trans. N.Z. Inst., vol. 43, pp. 378-407. 

 McKay, A., 1884. On the North-eastern District of Otago, Rep. Geol. 



Explor dur. 1883-84, pp. 45-66. 

 Park, J., 1905. On the Marine Tertiaries of Otago and Canterbury, 



with Special Reference to the Relations existing between the Pareora 



and Oamaru Series, Trans. N.Z. Inst., vol. 37, pp. 4S9-551 (ref. to 



pp. 506-7). 

 ■ 1911. The Unconformable Relationship of the Lower Tertiaries 



and Upper Cretaceous of New Zealand, Geol. Mag., dec. 5. vol, 8. 



pp. 539-49. 

 Speight, R., 1915. The Intermontane Basins of Canterbury, Trans. N.Z. 



Inst., vol. 47, pp. 336-53. 

 Thomson, J. A., 1914. Mineral Prospects of the Maharahara District, 



Hawke's Bav, 8th Ann. Rep. N.Z. Geol. Survey, Mines Statement, 



pp. 162-70. 

 — — 1916 (No. 1). On Stage Names applicable to the Divisions of the 



Tertiary in New Zealand, Trans. N.Z. Inst., vol. 48, pp. 28-40. 



1916 (No. 2). The Flint-beds associated with the Amuri Limestone 



of Marlborough, Trans. N.Z. Inst., vol. 48, pp. 48-58. 

 Ulrich, E. O., 1911. Revision of the Palaeozoic Systems, Bull. Geol. Soc. 



Am., vol. 22, pp. 281-680. 

 Willis, B., 1910. Principles of Paleogeography, Science (n.s.), vol. 31, 



pp. 241-60. 

 Wood, H., 1917. The Cretaceous Faunas of the North-eastern Part of the 



South Island of New Zealand, N.Z. Geol. Surv., Pal. Bull. No. 4. 



