260 NERBUDDA DISTRICT. 



on the west to the Ganges alluvium on the east, we will find equal 

 difficulty in reconciling this estimate with facts. The explanation sug- 

 gested above is very unsatisfactory, namely, that this direction was taken 

 from the range between the Nerbudda and the Taptee, and the prolong- 

 ation of that line south of the Sone. If however, as we have above shown, 

 the movement to which the ranges north of the Nerbudda and the Sone 

 owe their elevation, was certainly separated in geological chronology from 

 that movement which traced the great fault lines along the south of those 

 rivers, by a geological era, by the period of a cycle of geological changes 

 as above defined, then it is simply an abuse of language to talk of the 

 ranges as due to one movement as their cause, and a false generalization 

 to group together the nearly parallel ranges, and taking an average 

 from the whole, to speak of that as the direction of a range, and the 

 result of a single effort of some internal force. 



Such considerations may remind the geological reader of some of the 

 difficulties of arriving at a satisfactory estimate of the simple direction 

 of any hill range, when looked at in the light required by the theory 

 under discussion. 



After having overcome this difficulty, which is in our case reduced 

 to a minimum by the exceptionally sharply defined line of the Vindhyan 

 scarp, (and indeed also of the- Mahadeva fault) and having so satisfac- 

 torily determined the direction of two such ranges as to feel safe in apply- 

 ing mathematical calculation to the result, we proceed to compare these 

 directions. In our case the two such ranges just mentioned, are unne- 

 cessary ; for we use M. de Beaumont's 20 European systems as standards 

 of reference, and have to determine which (if any) among them was 

 synchronous in origin with the Indian range whose direction we have 

 fixed. 



In attempting to investigate the parallelism of two lines so far apart on 

 the sphere as those with which we have thus to do, it is evident that 

 the question is not one of ordinary plane-surface parallelism. The 



