Glacial Action in Australasia. — Hitchcock. 257 
One would think, however, from the large number of 
American Carboniferous genera recorded in the Mesozoic of 
this region, that the paleontological break may have been ex- 
aggerated, as the following list of Australasian Mesozoic gen- 
era may indicate: Pecopteris. Neuropteris, Sphenopteris, 
Thinnfeldia, Cyclopteris, Treniopteris, Odontopteris, Sagenop- 
teris, Alethopteris, Phyllotheca, Annularia, Podozamites, Pter- 
ophyllum, Otozamites, Sphenozamites, Brachyphyllum, Tax- 
ites, Sequoites, Walchia, Cunninghamites, Araucarites, Bai- 
era, Salisburia, Ginkgophyllum, and Zeugophyllites. 
At the close of the Mesozoic era in this region, allits rich 
and varied flora in turn disappeared, to be succeeded by new 
forms. This change was isochronous with important eruptions 
of the later greenstones, and some indications of attendant gla- 
cial phenomena are discovered. 
CONCLUSIONS. 
1. Glaciers must have existed in Australasia, India, and 
South Africa, at about the close of the Permian and opening 
of the Triassic period. 
2. An elevation of from 8,000 to 10,000 feet above the 
present sea level, under existing climatic conditions, would 
seem to be required to allow glaciers to accumulate. 
3. If these various countries were united by land areas 
in the Triassic period, with the possible additions of South 
America and Antarctica, the greater part of that early conti- 
nent must have been depressed abnormally in later times, with 
no apparent relation to existing land. 
4. These early glaciers probably were not of great conse- 
quence, as their locations correspond, in nearness to the equa- 
tor, with those of Pleistocene glaciers in Syria and northern 
Africa. They do not seem to have been continental in their di- 
mensions. 
5. If there have been several periods of cold, interspersed 
with times of tropical heat, there will be a greater necessity for 
the invocation of astronomical causes for the lowering of the 
temperature. 
