Brnson.—Palaeozoic and Mesozoic Seas in Australasia. 9 
confluent at the southern and western extremities. The knot itself would 
appear to arise as-the result of the mutual interference of the Tethyan 
and Pacific controls. Schuchert (1916) declared that eastern Australia 
and New Zealand were separate geosynclines in Palaeozoic times, and that 
the latter remained such during Mesozoic, and (he unexpectedly adds) 
during Cainozoic times also. The area now occupied by the Tasman Sea 
Zealand having been first sundered during Triassic times, when, by a 
curious error, he believes the last two regions to have been entirely land 
areas. 
Wilekens (1917), acutely summarizing many contradictory accounts, 
suggested a comparison between the structure of the European Alps and 
those of New Zealand, which appeared to him as probably asymmetric 
and thrust to the south-west and west against the gneissic massifs of western 
Southland and Fiordland, and to the north-west against a foreland of 
folded Palaeozoie rocks, now mostly foundered beneath the Tasman Sea, 
except for the area forming the mountains of the north-western portion 
of the structure of the Southern Alps. A somewhat similar hypothesis 
was independently formulated by the writer (Benson, 1921). 
lkom's (1918) careful discussion concerns Mesozoic times chiefly. 
He conceives that at the commencement of this period a single undivided 
continental mass extended throughout Australasia, New Guinea, and Fiji, 
and that its fragmentation with permanent enlargement of the Pacific Ocean 
commenced at this time. Epicontinental Triassic rocks were deposited 
in New Zealand and New Caledonia, and a temporary northward extension 
of the southern orean formed a gulf extending towards Sydney. The sea 
apparently are considered to have been somewhat later. This wide extent 
of land, which is assumed to have extended east of the present coast-line 
of Australia, has recently been named “ Tasmantis," the term being defined — 
as indicating “those portions of New South Wales and Queensland cut off 
from the remaining parts of Australia during the Carboniferous period 
[which] were parts of a separate land area which existed to the east of the 
Australian continent at least as far back as the beginning of the Devonian 
the close of the Carboniferous period" (David and Siissmilch, 1919). In 
this conception of an important geosyncline separating, until the close 
of Carboniferous times, the Australian nucleus from that now subsided 
beneath the Tasman Sea we have a marked accord with Schuchert's (1916) 
suggestions. 
