1877.] 0, Feistmantel — Giants' -Kettles in Rajmahal District. 77 



4. On Giants' -Kettles (pot holes), caused hy water action in streams in the 

 Majmahal Hills and Barakur district. — By Dr. 0. Feistmantel. 



(Abstract.) 



Giants'-Kettles, or ' pot holes' as they are described in Handbooks on 

 Geology and Physical Geography, are more or less regular cavities of various 

 sizes in diameter and depth, excavated in all sorts of rocks. They were 

 first described from Sweden, in 1769, and later |rom other localities ; and 

 various mythic stories were brought into connection with them in former 

 times. 



Eut while in most cases the Giants'-Kettles were shown to have been 

 produced by running water, by cataracts in streams, &c., and to be of recent 

 age only, yet for some others another time and cause was assigned, and they 

 were found to have their origin in that post-tertiary time, which is termed 

 the glacial period — and from this point of view they are certainly of geolo- 

 gical interest. 



As the author had observed the same forms in two different localities 

 in Bengal, and as there is, so far as he knew, only one case from India 

 recorded, he thought himself justified in describing those cases he had 

 himself observed. They are a contribution to those forms which are pro- 

 duced in present times, apparently by running water in streams, and will 

 certainly not be without interest especially for geologists in Europe, where 

 similar forms are better known and thought worthy of description. 



Last year he observed Giants'-Kettles in the Rajmahal Hills, in the 

 Bansloi Nuddee, E. S. E. from the village Amraj^ura. In the Rajmahal 

 district this river runs in a bed of trap-rock, which is often very hard, and 

 in this rock also the pot holes are excavated. 



At the time when he visited this place, there were two complete pot- 

 holes in the river bed, with circular apertures and pretty deep ; one was 

 larger than the other, the diameter of its aperture being 96 c. m., the depth 

 120 c. m. ; the other one measured 98 c. m. in diameter and Qf c. m. in depth. 

 Both were polished inside and shewed circular ridges, which might indicate 

 certain periods of excavation. In one of them there was water at the bot- 

 tom, in the other one a heap of sand. 



, Close to these were two others, through which at that time water was 

 flowing, having a distinct " affluent" and " effluent" channel, and producing 

 a regular whirlpool in the cavity, in which sand and small pebbles were 

 rolling round ; there was no waterfall, the water flowing quite horizon- 

 tally. They shewed the same conditions as the other ones only that 

 they were not yet so deep, but clearly indicated the way in which the 

 others also were produced. During the rainy season when the river is high, 

 the force of the running water is much more rapid and larger pebbles are 



