18 



BALL : GEOLOGY OF THE EAJMEHAL HILLS. 



successively deposited. As the area of deposit widened, overlap became an 

 inevitable result, not only between different groups, but also between 

 individual members of the same group. 



The very intricate boundaries of the several formations would 



Areas of different rock render it almost impossible to estimate the square 



s ° ups ' mileage by ordinary measurement. Recourse has* 



therefore, been had to weighment of the respective areas cut from a 



skeleton map. The following results were thus arrived at : — ■ 



Talchir group is exposed over 4 square miles. 



Barakar „ „ „ 70 „ „ 



Dubrajpur „ „ „ 60 „ „ 

 Trap with intertrappean series 



is exposed over ... 1532*5 „ „ 



Total ... 1666*5 square miles. 



The area of the metamorphic rocks, as the boundary in the accom- 

 panying map is a purely arbitrary one, has not been estimated. The same 

 remark applies to the laterite, alluvium, &c. 



It may be taken for granted, however, that the area occupied by 

 laterite exceeds that given for the trap, as it is not only co-extensive with 

 it in the hills, or nearly so, but also extends to a considerable extent into 

 the plains. 



In the following pages the rocks of the successive formations are 

 traced and described as they appear from the south to the north of 

 the area. 



( 172 ) 



