NOTES ON EARTHQUAKES. 
211 
geologists,, for a shift in the rock surface took place, and a “step” 
of rock, nine feet high, was raised for a distance of ninety miles. 
With regard to the depression of land by earthquakes, we 
may instance the large tract known as “ The Sunk Country,” 
at New Madrid, Missouri, which was submerged by earthquakes 
in 1811 and 1812. This depressed tract extends along the 
course of the White Water river for a distance of between 
seventy and eighty miles north and south, and for thirty miles 
east and west. The earthquake of Cutch, in 1819, caused a 
subsidence of land in one part of the delta of the Indus, and 
an elevation in another. In Sicily, in 1790, the ground at 
Maria di Niscemi, on the south coast, sank down in one place 
to the depth of thirty feet; while, during the tremendous 
Lisbon earthquake of 1755, the new quay, which was built 
entirely of marble, sank down to the depth of six hundred 
feet, carrying with it a great number of boats and small 
vessels, as well as a large number of persons who had fled 
there for safety. The effects of paroxysmal earthquakes in 
volcanic districts are so well known, and have been so often 
related, as to require no further description here. 
There is, however, another motion of the earth's crust 
which lifts and depresses whole continents, without any 
violent earthquake movements. We know very little respect- 
ing these great elevating and subsiding movements. Mr. 
Darwin believes, from the intimate and complicated manner 
in which the elevatory and eruptive forces are connected 
with volcanic phenomena, we may confidently come to the 
conclusion that the forces which at successive periods pour 
forth volcanic matter are identical with those forces which, 
slowly, and by little starts, uplift continents. Again, Sir 
Charles Lyell, in his “ Antiquity of Man,” remarks, that from 
what we do know of the state of the earth's interior, we 
must expect that the gradual expansion or contraction of 
different portions of the planet's crust may be the result of 
changes and fluctuations in temperature, with which the exist- 
ence of hundreds of active, and thousands of extinct volcanos, 
is probably connected. There are large portions of the earth's 
surface which have been elevated above the level of the ocean 
in Africa, in the north of Europe, South America, and other 
parts of the world, which bear no signs of paroxysmal upheaval, 
of volcanic overflows, or of any other than extremely equable 
movements. Sir Eoderick Murchison informs us, that there 
are in Russia large areas, consisting of rocks of the age of the 
Lower Silurian deposits, which have been but partially hardened 
since they were accumulated, which have never been pene- 
trated by volcanic matter, and have undergone no great 
change, or disruption, during the enormous periods which 
