EFFECTS PHODUCED UPON BUILDINGS. 133 



good foundations, consists in tlie fact that they have either 

 been of small extent or else have been observed only in 

 the neighbourhood of lines which divided them from other 

 formations, which lines are always those of great disturb- 

 ances. 



At the end of his description of the Neapolitan earth- 

 quake of 1857, Mallet says that more buildings were 

 destroyed on the rock than on the loose clay. This, how- 

 ever, he remarks, is hardly a fact from which we can draw 

 any valuable deductions, because it so happened that more 

 buildings were constructed on the hills than on the loose 

 ground.^ 



Professor D. S. Martin, writing on the earthquake of 

 New England in 1874, remarks that in Long Island the 

 shock was felt where there was gneiss between the drift. 

 Around portions to the east the observations were few and 

 far between. He also remarks that generally the shocks 

 were felt more strongly and frequently on rocky than on 

 soft ground.^ 



From these examples, it would appear that the hard 

 ground, which usually means the hills, forms a better 

 foundation than the softer ground, which is usually to be 

 found in the valleys and plains. Other examples, how- 

 ever, point to a different conclusion. For instance, a civil 

 engineer, writing about the New Zealand earthquake of 

 1855, when all the brick buildings in Wellington were over- 

 thrown, says that ' it was most violent on the sides of the 

 hills at those places, and least so in the centre of the 

 alluvial plains.' ^ 



In this example it must be noticed that the soft 

 alluvium here referred to was of large extent, and not loose 

 material resting on the flanks of rocks, from which it was 



1 Am. J. Sci. X. 191. 



* Eejjorts of British Association, 1 858, p, 106. 



