354 



On the rocks of the Damuda group. 



[No. 4. 



( Upper Panchits, 

 i Lower Panchits, 



500 



1,500 



^ Raniganj series, 



5,000 



... < Iron stones,... 



1,500 



v Lower Damiidas, ... 



2,000 







800 





11,300 



The rocks of the Raniganj field and their approximate thickness in 

 feet, are, in descending order, 



1. — Panchit group, 



2. — Damuda group, 

 3. — Talchir group, 



Of these heds the Damuda group alone contains coal. This 

 enormous thickness of beds is cut off on the south by a fault, the 

 downthrow of which cannot be less than 10,000 to 1-1,000 feet. 



The lowest or Talchir group, first separated in 1S56 from observa- 

 tions in Orissa, consists of a series of fine sandstones and mudstones, 

 frequently of a peculiar greenish colour, and becoming coarser 

 towards the top, while towards the base they are commonly com- 

 posed of the finest silt, in which there occur, in patches, gneiss 

 boulders of enormous size, some having been measured as much as 

 15 feet in diameter. It is most difficult to account for so anomalous 

 an occurrence as that of these huge blocks in the finest mud, for any 

 current which could roll or even move the former would necessarily 

 sweep away the latter, and although such a phenomenon appears 

 absurd in India, judging from the climate of the present day, the 

 action of ice, probably of the form known as ground ice, appears to be 

 the only geological agent which can account for all the circumstances, 

 by explaining the transport of the boulders. 



The Talchir group had not undergone a very great amount of de- 

 nudation, prior to the deposition of the Damuda rocks. It is, however, 

 completely overlapped in the eastern portion of the Raniganj field, 

 although well developed in the west. Very few fossils have as yet 

 been obtained from these beds, those found are entirely plants, and 

 shew distinctions from Damuda forms. 



Beds belonging to the Talchir group have now been discovered in 

 Orissa, in Central India, in Beerbhoom, where they occur in numer- 

 ous scattered patches, and in one or two places on the west side of the 



