410 
PACIFIC EXPLORATION: C SCHUCHERT 
era in diminished extent throughout the Mesozoic and even into Plio- 
cene time. This may be known as the New Zealand trough, a far nar- 
rower but much longer one than that of Australia; the shorter southern 
portion has now risen into the mountains of New Zealand, while the 
far longer northern part has apparently subsided to a depth of not more 
than 9000 feet, forming a submerged plateau upon which stand the 
volcanic islands of the Kermadecs and the Tongas. 
In the New Zealand trough there appear to be, according to Park,^ no 
less than 45,000 feet of Paleozoic and 11,000 feet of Mesozoic sediments, 
all of which are apparently of marine origin. These are coarse in grain 
and have much interbedded igneous material, which indicates that the 
adjacent lands were unstable and repeatedly reelevated into high lands. 
There were at least four times when the New Zealand trough was mark- 
edly subject to folding and upHft; these were toward the close of the 
Silurian, Devonian, Jurassic, and Cretaceous periods. During the 
Tertiary, the New Zealand trough also appears to have been in continu- 
ous subsidence from late Eocene into Phocene time, when about 9000 
feet of marine sediments had been laid down along the eastern sinking 
margin. Late in the Pliocene there was marked vertical upKft, probably 
as much as 4500 and possibly even 6000 feet. The nearly horizontal 
Tertiary strata are now found in places at an elevation of 3000 feet, 
having been depressed 1500 feet during the time of Pleistocene glaci- 
ation. The high condition of New Zealand at this time united into a 
greater New Zealand all of the present outlying islands of the New 
Zealand plateau, no part of which is now submerged more than 3000 
feet. 
In AustraHa there is no evidence of the Tasman sea during Cambrian 
time, for the marine invasions at first are from the south and later across 
the entire medial portion of the continent. The trough begins to appear 
as a sea-way in the Ordovician (?5000 feet of deposits, according to Siiss- 
milch^), with the greatest time of subsidence during the Devonian 
(27,000 feet); it continued with some interruptions throughout the 
Carboniferous and Permian (36,000 feet). During the Paleozoic, about 
70,000 feet of essentially coarse sediments and interbedded volcanics 
were laid down in New South Wales, though smaller thicknesses seem 
to prevail elsewhere in eastern Australia. Here again we see the geo- 
logic results of high adjacent and often rejuvenated western lands. 
The record also shows that there were in Paleozoic time at least three 
periods of decided crustal folding (Ordovician, Silurian, and Devonian), 
and one of vertical uplift with faulting (during the close of Permian 
time). Following the Permian deformation, the continent was repeat- 
