ON THE FACTS OF BARTHQUAKE PH4Z NOMENA. 59 
surface of undulating country and of soft material may produce, and what 
shattering and breaking up into blocks, it may be capable of when acting 
thus from beneath upon countries consisting of stratified rock in a tolerably 
level and unbroken bed. 
Lastly, from crevices formed during an earthquake, water has been ob- 
served to pour out in vast volumes for a considerable time after their for- 
mation, at which moment they were dry, and within them the water slowly 
welled up at first. 
This case is not to be confounded with the obvious one of a crevasse having 
some underground communication with a higher source, then opened to it 
as a mouthpiece, for the first time, and the explanation of which is obvious ; 
but the following seems to be its solution: the crevasse, if formed in deep 
clay, as in Calabria, or Lisbon, or Jamaica, and rent down toa water-bearing 
stratum at its lowest parts, will have the base of its sheer sides soon sapped 
by the water at bottom and by that dripping from its walls, and there beginning 
to slip, its sides will gradually bulge inwards, first at the bottom, and this rising 
upwards slowly, the whole chasm will close in and gradually eject and press 
out over its lips, the whole of the water it had before contained, though this 
may have at first stood fathoms below the surface; and as the whole capacity 
of some of the crevasses we have seen is immense, and the closing up gradual, 
a large stream may thus be kept running from many of them for a long 
eriod. 
5 This gradual closing in (and no doubt from this combination of circum- 
stances) was remarked in many of the great crevasses of the Calabrian plain ; 
the enormous force with which the sides closed together, was remarked 
with wonder by those who dug out the remains of buried habitations, and 
found beams and masonry, furniture, utensils, and bodies of men and animals 
pressed together and compacted into one undistinguishable mass; but such 
a result will excite no wonder in those who have had an opportunity of 
carefully examining the phenomena and effects of any great landslip, or even 
slip of heavy embankment, or of the effects of the “creep and crush” in 
our deep coal pits. 
To such a subsidence taking place suddenly, no doubt, was due the dreadful 
disappearance of the quay of Lisbon in 1755, which became suddenly perched 
as it were upon the very brink of a vast crevasse, formed under the waters of 
the Tagus, which rapidly softening the blue clay upon which Mr. Sharp 
(Geol. Proceed. 1838, p. 36) informs us the lower part of the city is founded, 
soon caused tlie banks of the rent to yield under its overwater load; and to 
a similar cause must the sinking of the quay or mole at Messina be ascribed, 
which was built upon a submarine bank of clay and sand, sloping rapidly off 
into profoundly deep water close bys The water poured out from these 
spouting apertures or from large crevasses, has often been described as im- 
pregnated with foreign matters ; these have chiefly been described as “ hepa- 
tic, or sulphureous, or bituminous,” and have mostly been recorded as coming 
from the overflow of ‘crevasses some time after the earthquake; of course 
water-bearing beds full of soluble mineral matter will eject more or less of 
these with their fluid contents; but when such crevasses affect deep inco- 
herent formations containing sulphurets and organic matter together, rapid 
decompositions will give rise to all thosé horrible evolutions of foul water 
and poisonous gases that have been recorded so often, and especially in the 
Jamaica earthquake of 1692. 
If, for example, such wet crevasses as we have been considering were to be 
Operied in the deep carboniferous formations of Westphalia or Lower Saxony, 
or éven in some of our Own coal-measures, with what rapidity the coal and 
