History of New Zealand. 317 
and by Park.! A group of the lower-lying blocks determines a chain 
of basins, which have been known in the past as ‘‘ old lake-basins ”’, 
though no definite evidence has been adduced that they have been 
occupied by lakes. The depressions now occupied by large lakes 
still farther west—e.g. Wakatipu and ‘le Anau—were probably, 
as Andrews” notes, initially of thesame nature; but they have been 
subsequently profoundly modified by glacial erosion. In Central 
Otago the covering strata are largely of terrestrial origin and have 
been preserved over considerable areas on the low-lying blocks in the 
basins. If, as is probable, there was formerly a continuous or nearly 
continuous cover on the higher blocks also, it has been removed by 
erosion, with the exception of a few outliers. The general nature of 
the Kaikoura deformation is here decipherable, not only from the 
attitude of the cover in the basins, but also from the configuration of 
the higher blocks upon which extensive areas of a denudation plain, 
warped and dislocated by the movements, are preserved. As the 
plain dips beneath the cover on the flanks of tilted blocks and as it 
supports outliers of the same beds, it is, at least in great part, 
a stripped floor. Its virtual continuity with the stripped floor in the 
Oamaru district indicates with a high degree of probability that it is 
a part of the same erosion surface, though perhaps not covered until 
a later date and perhaps never submerged. ‘The majority of the 
blocks in Central Otago are elongated, trending north-east and south- 
west, and are tilted towards the north-west, presenting scarp-faces 
towards the south-east or east.* Kast of the centre of the district 
a considerable area of the denudation plain forms a more or less 
horizontal plateau at a height of about 1,000 feet. This has been 
_ealled the ‘‘ Central Otago Peneplain ” or Barewood Plateau.* 
In the North Island the absence of a continuation of the main 
mountain range—the Southern Alps—of the South Island has often 
been remarked upon, and the statements of Hutton °® and Suess * on the 
. Subject are perhaps correctly interpreted as indicating their belief 
that the north-eastern continuation of the Alpine range has subsided 
independently. In view, however, of the late date of the movements 
to which the South Island ranges owe their present height, and in 
view also of the presence in the North Island opposite those ranges of 
Tertiary rocks of greater age than the orogenic movements, it would 
be more correct to say that this portion of the North Island has 
merely not been uplifted to the same extent as the South Island. 
1 ““The Geology of the Area’ covered by the Alexandra Sheet, Central 
Otago Division,’’ N.Z. Geol. Sury., Bull. 2, p. 6, 1906; ‘‘ The Geology of the 
Cromwell Subdivision, Western Otago,’’ N.Z. Geol. Surv., Bull. 5, 1908. 
2 E. C. Andrews, ‘‘ Erosion and its Significance’’: Journ. and Proc. Roy. 
Soc. N.S.W., vol. xlv, p. 116, 1911. 
3 The structure of this district is well displayed by an excellent geological 
map by A. McKay in his Report on the older Auriferous Drifts of Central 
Otago, 2nd ed., Wellington, Govt. Printer, 1897 (opp. p. 84). 
4 J. Park, loc. cit., 1906 and 1908; Geology of New Zealand, 1910, p. 9. 
> F. W. Hutton, ‘* Sketch of the Geology of New Zealand ’’?: Quart. Journ. 
Geol. Soc., vol. xli, p. 197, 1885. 
' © #H. Suess, The Face of the Harth (Eng. trans.), vol. ii, p. 147, Oxford, 
1906. 
