PREVIOUS NOTICES. 11 



original speculations as to the origin of the crystalline rocks, and attri- 

 butes, as others have done before him, the spHtting-up and fracture of 

 the gneiss, &c., to the sudden transitions in temperature during the 

 winter months. I believe this agency to be wholly incapable of produc- 

 ing the results. Owing to the feeble conducting powers of stone, the 

 temperature of the atmosphere can only affect but a limited superficial 

 layer of rock ; moreover, with a sudden fall of temperature, the stone is 

 not immediately cooled, but gradually radiates forth its heat, which pro- 

 cess may be continued throughout the greater part of a night, as any 

 one who has camped near bare rocks during the hot weather is likely to 

 have a lively recollection of. 



jVTr. Forbes shews the accuracy of his powers of observation by 

 pointing out the existence of detached patches of sedimentary rocks at a 

 distance from the main areas. 



He then describes the coal- mining operations in the Daltonganj 

 area, and discusses the question of a light railway to connect the field 

 with the East Indian line. 



The discovery of copper ore by himself in Daltouganj is recorded, and 

 there is an interesting sketch of the native system of manufacturing 

 iron, to which reference will be made on a future page. 



Mr. Forbes alludes to the coal of the Aurunga valley, of which he 

 appears to have been the first discoverer. 



In an appendix, the reports on the coal by several of the above 

 authorities are quoted in full, the whole forming a valuable epitome 

 of the information available on the subject up to date. 



In his descriptive accounts of the country surveyed in Districts 



SamueUs, Captain, Hazaribagh and Lohardugga during tlie season 



-72.a 1871-73, Captain Samuells mentions the seams at 



Jugguldugga as containing, apparently, the best coal. Several localities 



a " Report on the Revenue Survey Operations of the Lower Provinces from October 18V1 

 to September 1872.—" Calcutta, 1873. 



i 11 ) 



