Dr. Cotton—Later Geological History of New Zealand. 243 
This species is only known to me from the Isle of Wight, where it 
occurs all over the island sparingly in the zone of Holaster planus and 
freely in the Chalk between the ‘ grey marl’ and the ‘ black marl’. 
It is very near akin to Biflustra lacrymopora, D’Orb.1; but the thick 
central lamina, the wide and clumsy-looking side walls and narrow 
_ area, and the total absence, as far as my experience goes, of ocecia 
seem full warrant for a specific separation which the very restricted 
horizontal and vertical range, and the great rarity of Biflustrine 
forms in our Chalk, would tempt one to make on slenderer grounds. 
EXPLANATION OF PLATE X. 
(All figures x 12 diams.) 
1. Membranipora missilis. Zone of Marsupites. Well, Hants. 
2. M. missilis. Zone of Marsupites. Brighton. i 
3. M. Fannia. Zone of A. quadratus. Shawford, Hants. 
4. M. Fanma. Part of the same specimen in a different light. 
6. M. cupolata. Trimingham. 
8. M. vectensis. Zone of Holaster planus. Culver Cliff, Isle of Wg 
(To be continued.) 
IJ.—Tax Srrevcrvure anp Later Gronogicat History or 
New ZEananp. 
By C. A. Corton, D.Se., F.G.S., Victoria University College, Wellington, N.Z. 
Tue Mesozoic Orocenic Movements. 
Ae is well known, the skeleton or oldermass? of New Zealand is 
largely composed of a mass of deformed sedimentary rocks, the 
‘precise ages of the members of which are in doubt but do not affect 
the problem under consideration. The most profound deformation 
of this vast sedimentary group took place in late Jurassic or early 
Cretaceous times during what may be termed the ‘‘ Mesozoic orogenic 
‘period”’, when probably a great mountain range came into existence. 
It was the opinion of Hutton * that the mountain range which 
resulted from the Mesozoic folding still survives in the present-day 
mountains of New Zealand ; but this view, though accepted by Suess,‘ 
is not specifically maintained by any modern New Zealand geologist. 
The contrary opinion has, however, rarely been expressed. * 
I Pal. Crét. Franc., v, p. 274, pl. 695, figs. 1-3. 
2 The writer employs the convenient terms ‘oldermass’ and ‘ covering 
strata ’ or simply ‘cover’ in the sense in which similar terms were introduced 
by W. M. Davis (“‘ Relation of Geography to Geology,’’ Bull. Geol. Soc. Am., 
vol. xxiii, pp. 93-124, 1912). ‘ Oldermass’ means a mass of rocks, generally 
of complex structure and of various ages, which have been planed down by 
erosion and which have been covered, during a later period of Bum eree nee, by 
a series of “ covering strata’. 
3 F. W. Hutton, The Geology of Otago, Dunedin, 1875, p. 10; see also 
“On the Geology of the New Zealand Alps’’, Proc. Roy. Soc. Tas., 1886. 
+ EH. Suess, The Face of the Earth, vol. ee p. 148, Oxford, 1906. 
> But see P. G. Morgan, ‘‘ The Geology of the Mikonui Subdivision, North 
Westland,’’ N.Z. Geol. Sury., Bull. 6, 1908, p.43; and also R. Speight, ** The 
Mount Arrowsmith District: Physiography,’’ Trans. N:Z. Inst., vol. xliii, 
pp- 319-20, 1911; ‘‘ The Intermontane Basins of Canterbury,’’ ibid., vol. xlvii, 
pp. 336-53 (p. 353), 1915. . ik 
