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SCIENTIFIC AND TECHNICAL SOCIETIES. 
‘At the September meeting the following papers were read:— 
1. Possibilities of Modifying Climate by Human Agency, with Special Ap- 
plication to South-Eastern Australia, by E. T. Quayle, B.A. 
The author seeks to’ prove— 
(a) That the clearing away of the Mallee forest covering, and the . 
‘substitution therefor of growing crops: and grass, cause a 
very appreciable increase in the rainfall over the country~ to 
leeward of the improved area, especially in spring. 
'(b) That similar results are observable in connexion with the irri- 
gation areas and Murray floodings. 
(c) That the increased evaporation from these areas mostly causes 
increased rainfall upon the mountains, and, therefore, results in 
increases in the water supplies available for irrigation. 
These claims are effectively supported by rainfall statistics, and by argu- 
ments based upon analyses of rain incidence with the various winds upon ¢he 
shores of Port Phillip Bay and Spencer Gulf, proofs being quoted that wet soils 
and growing vegetation evaporate as freely as water surfaces. - : 
Stress is laid upon the economic importance of these results. 
2. Revision of the Genus Pultenwa, Part IL., by H. B. Williamson. 
About thirty species of Pultenwa are dealt with in continuation of the 
previous paper. Affinities are discussed, and by means of short descriptions 
and diagnostic drawings it is sought to clear up many confused ideas regarding 
the genus. Four new species are described and five new varieties defined. Two 
species have been reduced to varietal rank, and one species has been restored. 
Mr. F. Chapman exhibited some remarkably well preserved fossil leaves, 
in which the venation stood out very distinctly. It was stated that this feature 
of the clear venation seems to be due to the absorbent condition of the pipe-clay 
matrix, which separates the humic acid and other products of partial decom- 
position, The leaves shown were all of Triassic age (Ipswich series), from 
Petrie’s Quarry, Rrisbane, and included the Maidenhaiy trees and allies (Ginkgo 
and Baiera) and a Fern, Teniopteris. 
Mr. H. Barkley exhibited some interesting examples of Fractures in Glass. 
ROYAL SOCIETY OF NEW: SOUTH WALES. 
At the September meeting the following papers were read:— 
1, “ The Volcanic Neck at the Basin, Nepean River,’ by Mr. G. D Osborne. 
The general geological features of the neck were discussed, and a detailed 
account of the petrology of the rocks occurring there is given. 
The neck, which breaks through the Triassic rocks at its surface out- 
crop, is filled with a fine-grained breccia, which is intruded by basalt dykes and 
plugs. ‘The formation of the neck with the production of a long narrow vent 
has been effected by explosive action concentrated upon a weak fissure stricture 
lying transverse to the monoclinal fold in that locality. 
‘The Basin Neck has played an important part in the physiographic history 
_of the Warrangamba and Nepean River systems in Cainozoie times, the present 
junction of these two rivers being within the Neck. 
The neck, one manifestation. of Tertiary vuleanicity, is genetically con- 
nected with the differential epeirogenic disturbance and quasi-senkungsfeld 
formation which affected the Sydney-Blue Mountain area in Tertiary times. 
In the breccia there occur fragments of the peridotites cognate with basalt, 
and foreign xenoliths of rhyolite, gneissic granite, and sandy limestone. ‘The 
basalt contains only cognate inclusions of norites, hyperite, harzburgites, 
herzolites, dunites, pyroxenites, and troctolite, the latter recorded for the first 
time in New South Wales. The cognate inclusions represent fragments of a 
differentiate which solidified under plutonic. conditions. The rhyolite inclusions 
may have come from the southward extension of the Kuttung series, the granitic 
rocks from ancient terranes, and the caleareous clastic rocks from a now denuded 
roof of upper Wianamatta rocks. 
633: 
