551.79 19' 



V 



The Facetted Pebbles of India 



IT is now nearly forty years since the first account (1) of evidence 

 of ice action in Palaeozoic times and within the tropics was pub- 

 lished, and though the concept of a Permian glacial period is now one 

 of the accepted results of geological research, the opposition to its 

 acceptance is by no means dead. Some ten years ago this opposi- 

 tion received an access of strength by the arrival and exhibition in 

 England of certain peculiar fragments of rock, first discovered by Dr 

 Warth (2) in the Permian boulder beds of the Salt Eange, which 

 did not merely show a striation like that produced by glaciers, but 

 bore several surfaces or facets which met in obtuse angles, and some- 

 times completely surrounded the stone. A number of these were 

 sent home, unaccompanied by stones of other types, and an idea 

 seems, perhaps not unnaturally, to have sprung up that these were 

 the normal type of boulder, and not, as was the case, curiosities 

 which were strange to geologists in India, and sent by them to their 

 colleagues in Europe, with a view to enlightenment as to the mode 

 of origin of a feature with which they were not acquainted as a 

 result of ice action. 



Specimens were exhibited at the Geological Society (3), the 

 British Association (4), and elsewhere, and the general opinion may 

 be expressed in the words of a letter by Dr W. T. Blanford to the 

 Geological Magazine (5), that " the great difficulty in accounting for 

 the origin of these facetted blocks is that whilst the smoothed sur- 

 faces are in every respect similar to those on stones worn by glacial 

 action, no fragments from moraines, from boulder-clay, or from other 

 glacial deposits, are known to exhibit the peculiar facetting charac- 

 teristic of the present specimens." 



Such was the general opinion held by most, if not all, of- those 

 who saw the specimens, and in the museum at Zurich one of these 

 very facetted stones may be seen, with an endorsement on the label, 

 by Professor Heim, to the effect that he had seen nothing like it in 

 recent glacial deposits. 



In these circumstances, the facetted stones being supposed to be 

 the evidence on which was based the claim for a glacial origin of 

 the beds in which they were found, it was natural that the opposi- 

 tion to the claim should be strengthened. In reality, however, the 



