EARTHQUAKES. 75 
In all countries subject to earthquakes the point 
at which the effects are greatest is considered as the 
source or focus of the shocks. We forget that the 
rapidity with which the undulations are propagated 
to great distances, even across the basin of the 
ocean, proves the centre of action to be very remote 
from the earth’s surface. Hence it is clear that earth- 
quakes are not restricted to certain species of rocks, 
as some naturalists assert, but pervade all; although 
sometimes, in the same rock, the upper strata seem 
to form an insuperable obstacle to the propagation 
of the motion. It is curious also, that in a district 
of small extent, certain formations interrupt the 
shocks. Thus, at Cumana, before the catastrophe 
of 1797, the earthquakes were felt only along the 
southern or calcareous coast of the Gulf of Caria- 
co, as far as the town of that name, while in the 
peninsula of Araya, and at the village of Maniqua- 
rez, the ground was not agitated. At present, how- 
ever, the peninsula is as liable to earthquakes as 
the district around Cumana. 
In New Andalusia, as in Chili and Peru, the 
shocks follow the line of the shore, and extend but 
little into the interior,—a circumstance which in- 
dicates an intimate connexion between the causes 
that produce earthquakes and volcanic eruptions. 
If the land along the coasts is most agitated because 
it is generally lowest, why should not the shocks 
be equally strong in the savannahs, which are only 
a few yards above the level of the sea? 
The earthquakes of Cumana are connected with 
those of the West Indies, and are even suspected to 
have some relation to the voleanic phenomena of 
the Andes. On the 4th November 1797, the 
