248 Dr. C. A. Cotton—Later Geological 
Mesozoie orogenic period until near the end of the Tertiary were 
epeirogenic. This is contrary to the view of Hutton,’ who believed 
that folding movements affected the Cretaceous rocks in early Tertiary 
times, before the deposition of the remainder of the covering strata. 
THe Kaikoura Orogentc Movements. 
The orogenic movements which followed the Tertiary deposition, 
and to which the present relief is entirely or almost entirely due, 
must have occurred in or about the Pliocene period. The period of 
movement may be termed the ‘‘ Kaikoura orogenic period ”, since the 
Kaikoura ranges were the first to be explained by Hector’ and 
McKay* as owing the whole of their elevation to these late earth- 
movements. It cannot, however, be definitely stated at present 
whether the- orogenic movements began contemporaneously all over 
the region. Far too little is known as yet of the ages and correlations 
of the members of the covering strata to allow us to arrive at 
a conclusion on this point. 
The immediate cause of the disturbance may have been compression, 
for, in Central New Zealand at least, compression in a north-west and 
south-east direction accompanied the movements. In Marlborough 
the uplifted and depressed areas are elongated with a north-easterly 
trend, and major faults, some of which are certainly reverse faults, 
trend in the same direction, as do also folds in the previously 
horizontal covering strata. Perhaps owing to the rigidity of the 
oldermass, the strata of which had previously been folded on other 
lines and would strongly resist the new folding, the region was 
broken up into a number of ‘blocks’ bounded on one or more sides by 
faults, folding being generally subordinate to faulting except in the 
higher members of the covering strata, where the resistance of the 
rigid floor had least effect. 
In recent years, wherever detailed geological work has been done, 
evidence has accumulated of the importance of the part played by 
young faults in the structure of New Zealand, as may be found by 
reference to the accounts of the structure of parts of Westland, 
Nelson, Otago, and Auckland by Bell, Morgan, Park, Henderson, and 
others in the bulletins of the Geological Survey, and to a paper by 
Henderson * in which much information regarding faults in Western 
Nelson is brought together. 
While in a few cases the recognition of these faults rests on the 
evidence of fault-scarps or fault-line scarps, the majority of the 
faults described are such as bring the covering strata against the older 
rocks. Many other faults less easily detected by purely geological 
August 18, 1915, Dr. J. Henderson stated that in Western Nelson a suc- 
cession of similar movements had taken place. In these cages, however, 
during and after the movement, accumulation of sediment went on in the 
immediate vicinity on an undisturbed sea-floor. 
1 Geology of Otago, Dunedin, 1875, p. 76. 
* Progress Report, Rep. Geol. Expl., 1888-9, p. liv, 1890. 
> ‘*On the Geology of Marlborough and South-East Nelson,’’ pt. ii: Rep. 
Geol. Expl., 1890-1, p. 7, 1892. 
2 dio Hendercen: On the Genesis of the Surface Forms and Present 
Drainage-systems of West Nelson ’’: Trans. N.Z. Inst., vol. xliii, pp. 306-15, 
1911. 
