1843.] Memoir on Indian Earthquakes. 1037 



referred it. The intensity of the shock was much greater at Umpoo- 

 sie than at any place to the Westward, and it may thence be inferred, 

 that, as its direction was from Northward to Southward, it originated 

 in the upper portion of Gurhwal, a locality from which so many of the 

 Earthquakes just recorded have emanated. 



Earthquake of the 7th September, 1842. — This Earthquake was 

 very slight and unimportant, except from the circumstance of its 

 having been accompanied by an electric shock. There is nothing in 

 the information furnished regarding it to enable us to form any 

 decided opinion as to its place of emanation, and it is only on the 

 ground of a slight probability that I refer it to the Central Himalayan 

 tract. 



From the preceding details it appears, that including the Kamaon 

 shocks of May 1817, fifty-five Earthquakes have been experienced in the 

 interior of the Himalayas since 1803, by far the larger portion of which, 

 may without doubt be assigned to the action of disturbing forces, seated 

 under the main axis of this great mountain range. The unrecorded 

 shocks bear in all probability a large proportion to those recorded, and 

 the preceding statement therefore affords but an inadequate representa- 

 tion of the activity of the forces to which the shocks are due. Before 

 leaving this part of the subject, I may very briefly allude to the physi- 

 cal constitution of the central range of the Himalayas. By the uni- 

 form testimony of observers who have penetrated to the Snowy Range, 

 it appears that the mountain masses there are composed of primary 

 Rocks, that granite, gneiss and mica slate are chiefly developed, that 

 trap dykes, having a direction parallel to that of the main chain 

 itself have been found, and that signs of very powerful disruptive action 

 are continually apparent. These facts are all characters of the loca- 

 lities from which Earthquake shocks have been found to emanate in 

 other parts of the world, and are consistent with what, a priori, we 

 would be led to anticipate, whether we suppose Earthquakes to origi- 

 nate in the movements of a central fluid nucleus, or in the action of 

 more limited and local forces of chemical or mechanical origin, it is 

 natural to infer that their effects will be more perceptible in localities 

 where the solid crust of the earth is fissured and disturbed, and where 

 many " lines of least resistance", so to speak, are furnished, than in 

 others where the strata are more continuous and, unbroken. Hence it 

 has been found that in South America, in Italy, and in Scotland, 

 Earthquake tracts are characterised by marks of violent disruptive 

 action, and indications of the existence of subterranean volcanic forces 

 invariably to be discovered. There is yet another point of analogy 

 between the Earthquake Tract of the central Himalayas, and such 

 tracts in other countries, in the extraordinary prevalence throughout 

 the former of hot springs of very high temperature. Some of thes 

 I will now mention ; commencing with the most celebrated, those 

 of Jumnoutri at the source of the River Jumna, 10,849 feet above the 

 level of the Sea. Captain Hodgson, thus describes these springs un- 

 der date 21st April 1817, (Asiatic Researches, vol. XIV. p. 147.) 



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