72 The N.Z. Journal of Science and Technology. [Mar. 
sea capable of simulating the greater ocean in the mode of treatment and 
deposit of the residue brought into it ” (1897, p. 107). 
Park has described the quartz grits as marginal facies of lacustrine 
deposits, forming, at least in some cases, as for example in the Manuherikia 
and Ida depressions (1906, pp. 18, 24), the closing member of the series ; 
and a similar view was held earlier by Hector (1869), who described the 
grits as deltaic deposits filling lakes. McKay, however, has shown that 
the grits emerge from under younger beds to crop out near the junction 
of the covering strata with the rocks of the undermass. He regards them— 
quite correctly, it would appear—as near or at the base of the cover as 
developed at such places, and in his later accounts he insisted on their 
wide areal distribution. Elsewhere brown coal occurs in a similar way 
at the base of the sequence. 
In all cases the strata forming this cover have every appearance of 
wide-spreading rather than local formations, and it is obviously impossible 
to explain a widely extending bed of fine quartz gravel or greywacke gravel 
laid down with horizontal bedding as a lacustrine deposit. The lacustrine 
origin ascribed to the whole of the non-marine covering strata in Otago, 
though it has not heretofore been questioned, has certainly not been proved 
correct. 
The terrestrial Tertiary rocks of the North American Great Basin, 
formerly regarded as wholly lacustrine, have been shown in recent years 
to be largely of fluviatile origin,* and a similar origin seems equally probable 
for a great part of the covering strata in Otago. It seems that the question 
thus raised must remain open, however, until the beds have been carefully 
re-examined with the hypothesis of fluviatile deposition in mind. 
References. 
Cotton, C. A., 1916. The Structure and Later Geological History of New Zealand, 
Geol. Mag., dec. 6, vol. 3, pp. 243-49, 314-20. 
- 1917. Block Mountains in New Zealand, Am. Journ. Sci., vol. 44, pp. 249-93. 
Davis, W. M., 1899. Continental Deposits of the Rocky Mountain Region, Bull. Geol. 
Soc. Am., vol. 11, pp. 596-604. 
- 1900. The Fresh-water Tertiary Formations of the Rocky Mountain Region, 
Proc. Am. Ac. Arts Sci., vol. 35, pp. 345-73. 
Gordon, H. A., 1893. The Goldfields of New Zealand, Pari. Paper G.-3, Wellington. 
Hector, J., 1869. Progress Report, Rep. Geol. Explor. dur. 1868-69, p. vi. 
——- 1884. On the Deep Sinking at Naseby, Rep. Geol. Explor. dur. 1883-84, p. 44. 
Hutton, F. W., 1885, Geology of Otago, Dunedin. 
Marshall, P., 1911, New Zealand and Adjacent Islands, Handbuch der regionalen 
Geologie, Bd. 7, Abt. 1, Heidelberg. 
McKay, A., 1884. On the North-eastern District of Otago, Rep. Geol. Explor. dur. 
1883-84, pp. 45-81. 
-- 1897. Report on the Older Auriferous Drifts of Central Otogo, 2nd ed., Wellington 
(1st ed. as Pari. Paper, 1896). 
Park, J., 1906. The Geology of the Area covered by the Alexandra Sheet, N.Z. Geol. 
Surv. Bull. No. 2. 
-- 1908. The Geology of the Cromwell Subdivision, N.Z. Geol. Surv. Bull. No. 5. 
- 1910. The Geology of New Zealand, Christchurch. 
Thomson, J. A., 1917. Diastrophic and other Considerations in Classification and 
Correlation, and the Existence of Minor Diastrophic Districts in the Notocene, 
Trans. N.Z. Inst., vol. 49, pp. 397-413. 
* Their lacustrine origin was first questioned by Davis (1899 ; 1900). 
