ON THE FACTS OF EARTHQUAKE PHENOMENA. 61 
which he was then able to discover accompanying earthquakes on the coasts 
‘of Chili and Peru; in 1590 the sea rose over Chili for some leagues, leaving 
ships, dry far inland; in 1605 such a great wave swept away the greater part 
of Areca. In 1687 Callao was similarly overwhelmed, and ships were carried 
from the roadstead a league into the country ; the shock of this earthquake was 
felt by Wafer 150 leagues from the coast out at sea. He also saw at Santa, 
three miles from Callao, three rotting ships in a valley, where they had been 
carried inland over a low intervening hill in 1687. In 1746, Callao was 
again swept away, and vast heaps of gravel and sand left where it stood; 
large ships were thrown far inland by this wave. Lima has suffered in the 
same way with Cavallos, Guanape, Chancay and Guara, and the valleys of 
Barranea, Sape and Patevilea; when Penco was thus destroyed in 1751, a 
similar but less wave reached Juan Fernandez and overwhelmed houses 
along the shore. 
Mr. Alison (Pro. Geol. Trans. 1835) describes similar waves of the earth- 
quake of Chili of Feb. 1835; but it is unfortunate that no precise levellings or 
sections were made of the land swept over in any of these cases, or observa- 
tions of gravel boulders, &c. moved, which would have been highly important. 
This dearth of facts is the more to be regretted, because our theoretical 
knowledge is more perfect of liquid waves than of those of elasticity, as 
respects this our subject, and observations of the effects in denudation, trans- 
port, and effects on vegetable and animal life, producible by their agency, 
would have important bearing upon other extensive regions of geology ; 
and when facts and observations as to the precise effects produced by great 
sea-waves shall hereafter have been collected, it may provide geologists with 
a new instrument of investigation by which to trace upon many distant shores 
the evidences of ancient earthquakes, whose origin was below the ocean, 
and of which no other record remains capable of being investigated. 
In examining the many meagre notices of earthquakes which I have 
had occasion to collate in reference to this Report, I have been struck in 
several instances with notices of sudden recessions, and as sudden subse- 
quent unusually high risings of the sea, in various places where there was no 
account of any accompanying earthquake, either there or anywhere else at 
the same time. 
Thus of the Thames at London in 1762, and in 1767, of the sea at Malaga 
and at Leghorn in 1774, and in several other tidal rivers and estuaries, small 
but unusual fluctuations have been recorded ; some of these occurred in great 
éarthquake years, but there are no recorded shocks occurring anywhere at the 
times given for these fluctuations. 
I am disposed therefore not to attribute such to earthquake shocks at all, 
but to the sudden slippage under water of large masses of submarine banks 
of sand or mud. Where such banks accumulate in large masses, often, indeed 
generally, with one steep side next deep water, the progress of accumula- 
tion upon the top is equilibrated either by slow and gradual subsidation of the 
whole mass, or by sudden and partial slippages into deep water of portions 
of the mass; such a circumstance occurring upon a very moderate scale 
would be sufficient in a narrow estuary to produce a wave of translation 
liable to be mistaken for the effect of an earthquake. 
In thus examining in a more detailed and systematic manner than has 
previously been done, the secondary effects of earthquakes, I have been 
able, I trust, to cause the geologist to bear constantly in mind the broad 
distinction between the great cosmical forces of permanent elevation 
and depression, one of the secondary efforts of whose paroxysmal efforts 
_is the production of earthquakes, and the secondary effects of earthquakes 
