of the movement, he thinks, is not due to volcanic explosions,
but to the continual falling in of masses of rock which have been
fractured and upheaved in a solid form at a comparatively recent epoch;
but a longer series of observations would be requisite to confirm this
opinion. According to the same author, the height of several mountains
of the Andes has diminished in modern times.[473]

The great crest or cordillera of the Andes is depressed at the Isthmus
of Panama to a height of about 1000 feet, and at the lowest point of
separation between the two seas near the Gulf of San Miguel, to 150
feet. What some geographers regard as a continuation of that chain in
Central America lies to the east of a series of volcanoes, many of which
are active in the provinces of Pasto, Popayan, and Guatemala. Coseguina,
on the south side of the Gulf of Fonseca, was in eruption in January,
1835, and some of its ashes fell at Truxillo, on the shores of the Gulf
of Mexico. What is still more remarkable, on the same day, at Kingston,
in Jamaica, the same shower of ashes fell, having been carried by an
upper counter-current against the regular east wind which was then
blowing. Kingston is about 700 miles distant from Coseguina, and these
ashes must have been more than four days in the air, having travelled
170 miles a day. Eight leagues to the southward of the crater, the ashes
covered the ground to the depth of three yards and a half, destroying
the woods and dwellings. Thousands of cattle perished, their bodies
being in many instances one mass of scorched flesh. Deer and other wild
animals sought the towns for protection; many birds and quadrupeds were
found suffocated in the ashes, and the neighboring streams were strewed
with dead fish.[474] Such facts throw light on geological monuments, for
in the ashes thrown out at remote periods from the volcanoes of
Auvergne, now extinct, we find the bones and skeletons of lost species
of quadrupeds.

_Mexico._--The great volcanic chain, after having thus pursued its
course for several thousand miles from south to north, sends off a
branch in a new direction in Mexico, in the parallel of the city of that
name, and is prolonged in a great platform between the eighteenth and
twenty-second degrees of north latitude. Five active volcanoes traverse
Mexico from west to east--Tu[\x]tla, Orizaba, Popocatepetl, Jorullo, and
Colima. Jorullo, which is in the centre of the great platform, is no
less than 1