File:The Quarterly journal of the Geological Society of London (13889790057).jpg

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It is very remarkable that in
the Province of l^elson, where
there are several exposures of
granite in connection with this
system, and where the rocks are,
in places, violently disturbed,
metamorphic action has been
much less than in Otago, where
the rocks lie nearly flat and no
gTanitic areas occur. This mili-
tates much against Mr, Mallet's
idea that the heat of metamor-
phism is due to crushing. On the
other hand, the enormous thick-
ness of the system in Otago and
the gradual decrease of metamor-
phic action upward make it pro-
bable that, in this case, the meta-
morphism is due to the internal
heat of the earth.
Maitai System.
This system is found in the
South Island^ flanking the Takaka
System on both sides of the main
anticlinal (a, fig. 1), except in
Westland, where it has been almost
entirely removed. In the Korth
Island it forms the chief part of the
main range fromWellington to East
Cape (Eimutaka Series), as well as
most of the outcrops of old sedi-
mentary rocks in the Province of
Auckland. The rocks are chiefly
argillites, red and black slates, and
grey and green sandstones, with
occasional beds of limestone in the
South Island. Thick masses of
greenstone-ash are found interbed-
ded with the slates and sandstones
in many places in New Zealand,
but these rocks appear to be
local.
The thickness is estimated by
Dr. Hector at from 7,000 to 10,000
feet; but it is very difficult to
form an opinion, as the stratifica-
tion is often obscure.
That an unconformity exists be-