PC Se et eee aa eee eee i 
aoe and Natural History. 313 
Naples or on the a Le fee shore should not influence our judg- 
which was very severe in the promontory of Sorrento. Now the 
promontory and the ‘mand belon ong to the same geological forma- 
tion and are very near each oth 
n the other hand he er pis noticed by har 3“ Rossi in 
his instruments at Rome, and the various bate a he mentions 
in ihgpeicini with the jechenns earthquake, as fiapipnite g at that 
time near Rome, are not by any means necessarily connected with 
the Ischian earthen e. 
though in all Ischian earthquakes some commotion on the 
continent has been noticed, this commotion has invariably taken 
n 
a very considerable distance, while i e immediate 
mo va 
as been ejected from the many cones on the island one ¢ 
understand that there may be enormous cavities below the soil. 
en we consider the corroding influence of carbonic acid and 
water: and the great number of hot springs and the De ragiiahh of 
water they are eouttiaally pouring forth and have ring 
forth since time immemorial, that cavities may exist ee ty still 
t. 
If besides this, we remember that sufficient clay is being con- 
tinually taken out of the soil to furnish bricks, tiles and cooking 
cess is by no means a new one but has been going on for genera- 
tions; we see then causes tending still further to honeycomb the 
soil, The soil therefore being cavernous, a sudden collapse is not 
only possible but probable, and we can understand that it might 
produce remarkable effects. 
5) The great suddenness and Seen quae of the Ischian earth- 
quake, together with the absence of any volcanic phenomena, 
should induce us to seek some othe cause for the earthquake than 
a volcanic one; and as we have a set of conditions in the nature 
of the ground itself amply sufficient to account for most of the 
phenomena, we are justified, in the absence of further evidence, in 
considering this as an efficient cause. Whether ene acci ae 
i ssure, a seismic wave, or an explosion or what not, 
isa ce. which 0 only a teaurthetied ee methodical iter 
vation in ae Abr will enable us to find o 
+ teleain and its pr append: Subdivisions by J. 
D. Witter. aid M. E. Wapvswortn. pp. 331-566, of vol. vii 
of Bulletin of the Mus. Comp. Zool. Canibriage: August, 1884.— 
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