138 Note on Patna Boulders. [No. 2. 



this tract of country is ever subject to such sudden and extraordinary 

 irruptions as these stones and gravel would seem to indicate. 



15. From the rapid way in which the coarser stones decompose, 

 when exposed to the air, there can be no doubt that the whole of the 

 quartz sand found in this neighbourhood arises from the decomposi- 

 tion of these boulders, which may have been rounded by the action of 

 water or may be in their original forms. 



16. A sketch of the granite groups in the Barabar hills and of the 

 granite peak, Kowa D61, 365 feet high, in the same hills is given in 

 Lieut. Sherwill's geological map of Behar. 



17' The boulders there shown have evidently been rounded by the 

 wear arising from exposure to the air and the ordinary drainage of the 

 surface ; and no doubt beds of alluvial matter must have been deposited 

 to a considerable depth in their vicinity. These may have been either 

 transported to the!; °sent position by a deluge, or may have been 

 gradually carried there, or these stones and gravel may be portions of 

 rocks once similar to the granite groups in the Barabar hills, which 

 have been disintegrated in situ from the action of water or other 

 causes. 



18. Maccallcck in his geological classification of rocks under the 

 head of Alluvia, says, " In favorable circumstances of position, these 

 disintegrated rocks remain in their places forming beds or masses of 

 loose materials, consisting of larger fragments of the more solid parts 

 mixed with the clay and sand resulting from the more complete decom- 

 position of others. This occurrence takes place chiefly in granite." 



19. The following is a list of specimens to be despatched by 

 steamer.* 



Nos. 1, 2, 3. Stones taken from the top of the heap that has been 

 placed along the side of the road for metalling. 



No. 4. A broken one from ditto in a state of decomposition. 



No. 5. Taken out of the earth on the 7th June 1849, with a por- 

 tion of the clay in which these stones are found imbedded still adher- 

 ing to it. 



No. 6. A stone taken from the bottom of a heap by road-side. 



A few of the small shingle or pebbles which are found imbedded 

 amongst the large stones. A few of the bricks in which the stones 

 * Sutledge, now daily expected. 



