MUSSOORIE-DEHRA DUN EPICENTRAL TRACT. 79 



CHAPTER II. 



MUSSOORIE-DEHRA DUN EPICENTRAL TRACT. 



In the final part of Chapter I, it has been shown that the destruc- 

 tive energy of the earthquake, as recogn sect at the surface ol the 

 ground, showed such a well-marked decline between Larji and the 

 neighbourhood of Kot, and was followed as far as Simla by an area 

 so much more uniform and of so much less intensity, that we may be 

 said to have emerged from the epicentral and meizoseismal tract alto- 

 gether. This now-entertd-on area of much more uniform and less 

 intense destruction continues to surround the Kangra-Kulu epicentral 

 tract, and to be everywhere followed hy still wider zones of still less 

 intensity — except in one direction only, namely, that of the immediate 

 neighbourhood of Mussoorie and Dehra Dun, where a slight but marked 

 increase sets in. This has already been considered m my preliminary 

 report to indicate a second minor epicentral tract in the latter area. 

 Partly on this account and partly because of the importance of the large 

 towns of Dehra Dun -and Mussoorie, a separate description of this minor 

 epicentral area was desirable. Two officers of the Geological Survey were 

 deputed to this region, namely, Messrs. R. R. Simpson and K. A. K. 

 Hallowes, and the account now to follow is largely the result of their 

 work. It is supplemented, however, by a considerable number of inde- 

 pendent local accounts furnished by direct report and by the filled-in- 

 earthquake forms by officials and private residents. These are more 

 numerous than in the case of the Kangra-Kulu epicentral tract, where the 

 mortality was too great and where rescue and relief work were too 

 urgent in their demands to allow leisure for scientific reports. 



In geological structure the Dehra Dun and the surrounding part 



Geological struc- °* the hills resemble the Kangra Valley area on a 



ture. gm all scale. The valley of the Dun itself is occupied 



by sandy alluvium resting on sub-recent gravel deposits and consolidated 



debris fans which in their turn overspread the folded Upper Tertiary 



