114 Proceedings of the Asiatic Society. [April, 



produced by minor shocks, of which two at least preceded the 

 greater shock, and several succeeded it. He (Dr. Oldham) had been 

 able also to obtain some evidence tending to establish the angle of 

 emergence, at several points of observation, which would shew the 

 depth of the seismic focus, and also some readings of direction from 

 other places than Cachar, which all pointed to a position under the 

 Naga hills as being the source of the disturbance. Of all these full 

 details would be given in report. 



The most striking result of the earthquake, were the great fissures in 

 the surface, and the sinking and swelling of the surface over a large 

 area. These were certainly very remarkable, and had produced much, 

 damage, but they were in all cases only secondary results of the earth- 

 quake. They were exclusively confined to what was called by the people 

 of the country the bhurte (or ' filled in') land, there being no single case 

 of their occurrence in the kandy, which might be called the old banks, 

 of the river valley. But in every one of the many long curves which the 

 river Baruk forms below Cachar, and for scores of miles, these fissures 

 might be observed, greatest in amount near the river bank, but ex- 

 tending for miles across these peninsula-like extensions of the river 

 flats. The cause of them became evident after a very little examina- 

 tion. All the country referred to, is composed of some 30 to 40 

 feet thick of hard clay, and sandy clays, which for thousands of square 

 miles, rest upon a bed of 3 to 4 feet thick of bluish silt, or ooze, very 

 porous and being highly charged with water. In this wet state the 

 colour appears very much darker, and the whole looks of a deep greyish 

 blue. The bed is about the level of the river at its present low water,or 

 dry season height. The finely divided silt, or ooze, thus charged with 

 water, formed a highly slippery or unctuous bed, on which the slightest 

 motion would tend to make the heavy and more solid beds above to 

 move, or slide. The shock came ; this bed, and the large amount of 

 water in it, were disturbed, the support of the beds above weakened, 

 and in many places removed, and the necessary consequence was, that 

 they fell in. The moment motion commenced, the soft silt below was 

 squeezed out by the superimposed weight : and the entire thickness 

 of the beds above slipped down or slid out, on the greasy surface ; 

 this motion producing cracks and fissures. Frequently the sudden 

 pressure of this mass of some 30 feet thick above forced up the fine 



