296 JR. D. Oldham — On Homotaxis and Contemporaneity. 



the Talchirs, was noticed by the late Dr. T. Oldham. 1 That any- 

 special stress should have been laid on the resemblance was not to 

 be expected, for when the words were written the Glacial origin of 

 the Talchir boulder-bed had not been universally acknowledged, the 

 very idea of a Glacial epoch was still strange, and no one had yet 

 dreamed of a Palaeozoic Glacial epoch, still less of using such a con- 

 ception in the correlation of distant deposits. These observations 

 appear to have dropped completely out of sight, and when I found 

 that in Mr. W. T. Blanford's reply to Dr. Feistmantel 2 no notice was 

 taken of this resemblance, although Mr. H. F. Blanford's suggestion 

 that the Glacial beds of the Permian in England and the Talchirs in 

 India were contemporaneous is quoted, I concluded that private 

 information of later date had led to a modification of the views 

 expressed as to the lithological resemblance of the beds. 



Nevertheless, when visiting Australia in 1885, 1 determined to pay 

 special attention to this point, and was not surprised, on examining 

 the section west of Newcastle, to find that the marine beds showed 

 abundant traces of Glacial action. Blocks of slate, quartzite and 

 crystalline rocks, for the most part subangular, are found scattered 

 through a matrix of fine sand or shale, which contain delicate 

 Fenestellce and bivalve shells with the valves still united, showing 

 that they had lived, died and been tranquilly preserved where they 

 are now found, and proving, as conclusively as the matrix in which 

 they are preserved, that they could never have been exposed to any 

 current of sufficient force and rapidity to transport the blocks of 

 stone now found lying side by side with them. These included 

 fragments of rock are of all sizes, from a few inches to several feet 

 in diameter, the largest I saw being about four feet across in every 

 direction as exposed in the cutting, and of unknown size in the third 

 dimension ; and I was informed by Mr. Wilkinson that in these same 

 beds he has seen boulders of slate, etc., whose dimensions may be 

 measured in yards. 



It is impossible to account for these features except by the action 

 of ice floating in large masses, 3 and I had the good fortune to dis- 

 cover, during the course of a short morning's walk, in the railway 

 cutting near Branxton, a fragment beautifully smoothed and striated 

 in the manner characteristic of glacier action, besides at least two 

 others which showed the same feature, though obscurely. This 

 seems to show that the ice was of the nature of icebergs broken off 

 from a glacier which descended to the sea-level. 



Beds of similar structure and indicating a similar mode of origin 

 are also found at Wollongong, south of Sydney, and in the Blue 

 Mountains. Though these have not been traced into connection with 

 the marine beds west of Newcastle, the similarity of their position, 



1 Mem. Geol. Surv. Ind. vol. iii. p. 209 (1863). 



2 See. G. S. I. vol. xi. p. 148 (1878). 



3 Roughly speaking, it may be said to take 26 cubic feet of fresh-water ice floating 

 in sea- water to float a cubic foot of granite, or 14 cubic yards to float one ton. It 

 must be remembered that many of these fragments probably came from a distance, 

 and that the ice was melting all the while. These figures must be reduced by two- 

 fifths if the rock is supposed to be immersed. 



