1877.] O. Feistmantel — Giants' -Kettles in Bajmahal District. 79 



holes which Dr. Feistmantel had brought forward, and up to the present 

 moment he had been unaware that any competent geologist had question- 

 ed its validity. The phenomena was indeed exceedingly common and its 

 explanation generally obviouS. The most striking circumstance connected 

 with pot-holes was the great depth they occasionally attain to, with a very 

 small diameter. 



Dr. FEiSTMAJiTTEL Said he doubted very much whether Mr. H. F. Blan- 

 ford's statement, that these pot-holes are exceedingly common, is correct ; 

 otherwise they would have been more frequently -iioticed and described, and 

 authors like Nordenskjold, Jackson, Collegno, Kutorga, Helmersen, Boger 

 and Reusch would not have devoted special papers to their description ; and if 

 they were so very common in India, some of the Officers of the Geological 

 Survey, who visit different jDarts of India, would have observed them and 

 we should find altogether more information about them — if, however, it 

 was a fact that they are so common he would be very much obliged to Mr. 

 H. F. Blanford if he could furnish him with more positive information 

 about their occurrence, their size, &c., than is contained in the simple asser- 

 tion " that they occur" which could be found in any Handbook of Geology, 

 he did not, however, consider this general description sufficient,especially when 

 he saw that the authors above named had devoted special monographs to 

 these phenomena and taken the trouble to explain the different causes of 

 formation, which they certainly would not have done if pot-holes had been 

 so common, or always so apparent as Mr. Blanford seemed to think, and he 

 would recommend these papers to Mr. Blanford' s consideration. 



As regards the occurrence of pot-holes in European streams, it is cer- 

 tain that they are not quite so common ; Dr. Feistmantel had himself 

 visited many streams but had seen no pot-holes and the few scattered 

 communications about them would show that they are not so frequent, 

 except only in certain regions. 



The chief point Dr. Feistmantel intended to be show^n in his paper, 

 was that the polished surfaces of the rocks and the longitudinal furrows, 

 were, in the ca .es noted, produced by water action and not by ice ; and in the 

 paper he also shows still another cause of polishing and scratching and 

 gives some notes regarding a glacial time in the Talchir (Damuda) period. 



To Mr. Blanford' s questions whether there were any pot-holes explain- 

 ed by* glacier action he would reply that he did not mean that they were 

 produced by glacier action, but that the origin of some of them is put 

 back so far as to the times of the glacial period — and this is indeed so, as 

 shown in Messrs. Boger and Reusch's paper on Giants' -Kettles from near 

 Christiania.* The great Russian geologist, Mr. Helmersen, also speaks of 



* Quart. JoTirn. Geolog. Soc. 1874,, p. 750, und Zeitschrift der Deut. Geol. 

 Ges. 1874, p. 783, Pts. XXII— XXYIII. 



