198 NATURAL SCIENCE [September 



supposition that these facetted pebbles were in some way the result 

 of ice action was based on the fact that they were found in beds 

 which, on quite independent grounds, were believed to be of glacial 

 origin, and this belief would have been in no way affected if the 

 facetted stones had been shown to owe their peculiar form to any 

 other agency than ice. 



All this while, however, there was on record the description of 

 boulders of precisely similar character in glacial boulder clays of 

 Post-Tertiary age. In 1879 Professor Credner published an account 

 of the scratched stones found in the neighbourhood of Leipzig, (6) in 

 which he mentions three types ; the first being those on which a 

 fiat surface had been ground away on one side ; the second com- 

 prising those on which two or more such surfaces are found meeting 

 in obtuse angles ; the third, those which show no facets, but are of 

 a rounded or sub-angular form, and bear grooves and scratches 

 scattered over their surface. It would be impossible to give a better 

 classification of the stones found in the boulder beds of the Salt 

 Range, and the closeness of resemblance is only enhanced when 

 Professor Credner's detailed description is read. 



This account appears to have been overlooked by all those who 

 saw the Salt Range specimens, for which small blame can be laid, 

 as the volume of glacial literature is so vast that the greater part 

 must remain unread — even by those who devote themselves specially 

 to this subject — and the paper might have remained unnoticed in 

 this connection had it not been accidentally stumbled on while a 

 very different line of research was being pursued. Struck with the 

 light it threw on the origin of these curious pebbles I wrote to 

 Professor Credner asking for further particulars, and in reply was 

 informed that in the collection of the Saxon Geological Survey there 

 are a large number of ice-worn stones showing two or more facets, 

 meeting at an angle, and that in some these facets were distributed 

 round the whole circumference of the stone. He also informs me 

 that after a comparison of the specimens in Leipzig with the figures 

 and descriptions of Drs Warth (2) and Noetling (7),- he considers 

 that their nature as glaciated fragments of the same character as 

 those of the " griind-morane " of the northern ice-sheet is beyond 

 doubt. 



From this it is evident that we have, in Post-Tertiary glacial 

 deposits, ice- worn fragments showing all the peculiarities of those 

 found in the Permian boulder beds of the Salt Range, and with this 

 the last objection to accepting their glacial origin should disappear. 



R. D. Oldham. 



REFERENCES. 



1. Blanford, H. F. and W.T., and Theobald, W. — On the geological structure and rela- 

 tions of the Talcheer coalfield in the district of Cuttack. Mem. Geol. Surv. Lid., 

 i., pt. i., p. 33 (1859). 



