322 Scientific Proceedings, Royal Dublin Society. 



hunt Darcy, a little damage was done, the injured structures being 

 on the margin of the London clay. 



Feldon, Area of excessive Damage. — This extends W. N.^W. by 

 W., and E. S. E. by E., being bounded northward and southward 

 by small stream valleys, the maximum damages having taken place 

 at the southern and western margins. In this area the eiSects would 

 appear to suggest that the shock had a sort of rotary motion ; the 

 main direction, however, seems to have been southward, and the con- 

 cussion against the lines that form the southern and western boun- 

 daries appear to have caused the great destruction in those places. 

 The twist in the direction of the shock in the vicinity of the south- 

 ern boundary is exemplified by the twist in the chimney of Strood 

 mill, and in the damages that have been described as happening to 

 Dr. Green's house in the same vicinity. A well near Peldon is said 

 to have become quite muddy. 



Abberton and Langenhoe Area of excessive Damages. — This tract 

 extends about N.N.E. and S.S.W., its southern boundary being 

 the small stream valley that bounds the Peldon area on the 

 northward. The maximum damage seems to have happened in 

 the vicinity of Abberton, where the well is said to have remained 

 muddy for a few days. The shock appears to have been rotary, 

 but the general direction would seem to have been from the 

 southeastward, having concussion shocks from the boundaries, 

 which might account for the rotary appearance and the twisted 

 action observed at Langenhoe, where the church and glebe house 

 suffered considerably. 



To the N.E., at Fingrinhoe and Frenchman's Lane, the struc- 

 tural damages margin the tract of glacial drift previously refer- 

 red to. 



Colchester Area. — The maximum damage occurred in a nar- 

 row nearly east and west strip along the south Eoman wall, 

 from Head Gate to the valley of the Colne. South of this strip 

 very little damage was done, while northward it rapidly decreased, 

 scarcely any damage occurring north of the Colne river. From 

 the geological map by Mr. Dalton we learn that a narrow outcrop 

 of London clay occurs along the south wall, widening a little 

 towards the eastward, the excessive damage following this widen- 

 ing. North of this outcrop the damaged structures are on the 

 glacial drift, while on the alluvium at East Bridge there are some 



