68 
president’s ADDRESS — SECTION C. 
where Mr. Wilkinson had the previous year discovered some large 
erratics, which he believed to be ice-borne. The horizon in which tho 
erratics occur is that o£ the Permo-Carboniferous Upper Marine series, 
overlying the Greta coal-measures, and the beds are with little doubt 
homotaxial with the Middle Bowen series of Queensland, in which Mr. 
B. L. Jack had previously noted the occurrence of erratics. {Op. cit.) 
Mr. B. D. Oldham discovered near Branxton one boulder which 
he described as being “unmistakably striated and polished by ice.”* 
Mr. Oldham showed me this “boulder.” It was certainly 
minutely striated, and had a dull polish, but I should have hesitated 
about referring, without some reservation, the polishing and striation 
to glacial action, knowing how much has been accomplished in this 
direction by earth movements in beds constituted, like those at Branx- 
ton, of a mudstone matrix, through which fairly large blocks of rock 
are sporadically distributed. 
The larger erratics are chiefly of slate and granite, and some of 
them certainly weigh over a ton. They are associated in the fine 
bluish-grey mudstones with several varieties of the Fenestellidce and 
other delicate marine fossils, the perfect condition of which proves 
that the skeletons of the above organisms were deposited in tranquil 
sea water. This quite precludes the possibility of such erratics having 
been drifted to the position where they are now found by ocean 
currents. An ocean current strong enough to push along a block of 
granite weighing one ton would obviously crush to powder the delicate 
calcareous framework of the Feneslelhe, as Mr. 01 dh am points out. 
Mr. B. D. Oldham states {op. cit, p. 41) — “It is unfortunate 
for our present purpose that none of the subdivisions of the 
Gondwana series in India can be definitely and directly correlated 
with any of those of the Carbonaceous series, as exhibited in the 
Newcastle — [in New South Wales — T.AV.E.D.] — section, where their 
relative position is clear and free from doubt. But in Victoria there 
are some beds, containing Gangamopteris, known as Bacchus Marsh 
beds, which seem to be the equivalents of the Talchirs. * * * 
But their Palaeontology is not the only connection between the two, 
for, like the Talchirs, the Bacchus Marsh beds contain abundant 
evidence of the action of floating ice.” 
Mr. Oldham correlates the Bacchus Marsh beds with the Upper 
Marine beds at Branxton, New South Wales, and says — “It is 
impossible to account for the formation of such beds as these, except 
by the agency of floating ice in large masses ; and as both the Talchirs 
and the Bacchus Marsh beds show that when they were deposited the 
climate was much more severe than that now prevalent, we may take 
this as indicating that during their deposition there was a widespread 
glacial epoch corresponding to that which is know r n to have occurred 
in Post- Tertiary times.” 
On 4th September, 1885, Mr. C. P. Sprent published the follow- 
ing statementf : — 
“ The granite boulders of the Mackintosh — [Valley — T.W.E.D] — 
are of a very large size, some at least five tons in weight, and it is 
* Records Geol. Survey of India, vol. xix., pt. 1, p. 44. 
f “ Recent Explorations on the West Coast of Tasmania.” Trans, and Proc. Roy 
Geogr. Soc. of Austral., Vic. Br., vol. iii-iv., p. 58. 
