— 397 — 
pteris flora; and II: —by the persistence, very nearly at least, to the 
Permian, of the cosmopolitan flora in the province of Shansi in 
China (4). 
It is certain that Gondwana glaciation at an earlier date would have 
left its distinct imprint on the Northern flora. On the other hand the 
cosmopolitan character and uniformity in distribution of the latter 
forbid the admission of a glacial epoch between the base of the upper 
Carboniferous and theclose of the upper Coal Measures, which marks 
the disappearance of many of the Coal Measures types. From that time 
on the floral changes are relatively rapid, so that by the time we reach 
the Zechstein the great Carboniferous flora has essentially disappeared . 
For my own part, I am strongly disposed to regard the glaciation and 
approximate date of origin of the Gangamopteris flora as not earlier than 
the orogenic movements and floral changes which ushered in the 
Permian. It is, in my judgment, highly probable that a large part .of 
the Palaeozoic Gondwanas are later than the Rothliegende and that, 
should we find plants of Zechstein age (2) in still other regions of the 
Northern hemisphere, they would ba found to include additional 
representatives of the Gangamopteris flora. 
The Hawksbury conglomerate — supposed by some geologists to 
have resulted from a second ice invasion —appears to mark the beginning 
of the Trias in the Australian region, and, with it, tha disappearance 
of Gangamopteris and the characteristic composition of the older 
Gondwana flora. 
The question of the existence of Palaeozoic glacial deposits in 
South America ramains unproved (3). It may be noted, however, 
that Dr. Derby, in 1888, communicated to Waagen (4) the results of 
observations on boulder beds in Parana and Sao Paulo which he 
was inclined to regard as indicating the agency of drifting ice. 
Regardless of the lithological evidence for or against glacial action, 
we are led by the paleobotanical testimony to conclude that the 
boulder beds at the base of the coal-bearing series, and resting on 
(1) Von Richthofen, China, vol. IV, 1883, p. 209; also Abbalo, Pal. Italica, vol. VIs 
1900, p. 125. 
(2) The flora of the upper Permian, or Zechstein, of the Northern Province is meager 
and known in but few regions. 
(3) The author (David White) was not aware of the evidence found by the coal 
Commission, for the existence, of Glacial conditions in South Brazil at the beguinine 
of Permian time, and hence his conclusions are all the more remarkable, as well as 
confirmatory of Glacial conditions existing in Brazil during the epoch of the Orleans 
Conglomerate, I. C. W. 
(4) Rec. Geol. Surv. India, vol, XXII, pt. 2, 1889, p. 69. 
