/>30 On the Local and Relative Geology of Singapore, [June, 



down from above. There are undoubtedly cases which, if taken by 

 themselves, this explanation will satisfy. But when we seek to convert 

 this hypothesis into a general rule we are at once met by numerous 

 discordant appearances. Thus, of the extensive layers of rubble or 

 gravel-like fragments beneath a thick bed of clay which, as before 

 mentioned, are found on broad even summits of hills and ridges, there 

 are many where the clay is too compact and aluminous or the rubble 

 too fine, for the latter to have descended from the surface of the former, 

 and where there are no adjacent higher levels from which the former 

 could have been degraded and superimposed upon the latter. There 

 are other allied cases too which simple atmospherical causes will not 

 account for and which bring us to the next hypothesis — that of 



4. — Earthquakes. 



The instances alluded to are where the heads of the strata are not 

 merely converted into rubble and bent in the line of slope, but where 

 they are in zigzag, crooked, or sinuous lines ; — where adjacent layers 

 are differently and irregularly deflected out of their planes ; where the 

 rubble is here in large pieces lying in the direction of the proper plane 

 or of a regular curve from it, and there shattered into a confused mass of 

 small fragments, sometimes much thicker and sometimes much thinner 

 than the unaltered layer itself ; — or where fragments of one layer are 

 intermixed with those of an adjacent one, detached pieces of a sandstone 

 layer for instance imbedded in a layer of clay above it, or portions of 

 both layers confusedly mingled till all trace of their lines of demarca- 

 tion is lost. 



It is clear that no ordinary mechanical operations caused by atmo- 

 spherical forces could have produced such results, and that violent con- 

 vulsive movements of the earth have left these records. In the slight 

 earthquakes felt at Penang in 1843 it was remarked that the residents 

 on the hills described their effects differently from the residents on the 

 plain, or in language more exaggerated. In Belmont-house, which is 

 situated an the summit of a peaked hill rising freely out of the Pentland 

 chain, the tremor was particularly strong. Upon general mechanical 

 principles it is evident that the shocks will be most severely felt where- 

 ver the rocks acted on are freest. Through a dense homogeneous mass 

 extending uniformly in all directions equable undulations and vibrations 



