NERBDDDA DISTRICT. 259 



accurately parallel to each other. We shall here, however, confine our 

 attention to two only of these, namely, to that lying immediately to the 

 north, and to that immediately to the south of the Nerbudda Valley ; 

 the ranges of the Vindhyan, and of the Mahadeva faults, respectively. 

 Sacrificing much of the cumulative force derivable from the mass of 

 facts connected with all these range lines, we shall gain something in 

 thus simplifying our case. 



Taking first the Vindhyan range, with the intention of applying to it 

 M. de Beaumont's theory, in order to establish a synchronism between 

 it and some one of those European ranges whose geological date has been 

 fixed by his theory, the first difficulty we encounter is inherent in the 

 very initial step of the investigation : it is that of fixing the direction 

 of any given mountain range. 



The theory proceeds on the assumption that the elevation of a range 

 of hills is the result of a rectilinear fissure in the earth's crust ; and our 

 problem is to trace on a map the exact position of that fissure. Causes, 

 subsequent to this first origin of the range, must have changed the aspect 

 of the surface ; the accidents of denudation, and the resistance to its 

 forces, offered by unequal hardness in different parts of the rock masses, 

 must have indefinitely obscured the results of the original movements. 

 We have, however, to estimate, from the modified contours of the sur- 

 face, the exact position of this fissure line, which at best was one only of 

 many causes that contributed to fix the form of the hills and valleys of 

 which the range is made up. Captain -Newbold was an observer whose 

 accuracy and great zeal no Indian geologist will doubt. He assigned to 

 the Vindhyan range a direction of W. 5° S. But whether we take up 

 our best geographical maps, or refer to detailed observations on the 

 ground ; whether we take the range within its narrower limits, say from 

 Hindia to Jubbulpur, or trace it to its extreme (a) length from the sea 



(a) We exclude the hypothetical prolongations of the line fast of the Ganges, nor do<>* 

 Captain Newbold, as far as we know, take such into his estimate, 



