Beyond the dyke the road runs for some miles along the mountains and
hills, which all consist of lava, and are of a very dark, nearly
black colour. The stones on these hills were very loose; in the
plain below many colossal pieces were lying, which must have fallen
down; and many others threatened to fall every moment. We passed
the dangerous spot safely, without having had to witness such a
scene.
I often heard a hollow sound among these hills; I at first took it
for distant thunder, and examined the horizon to discover the
approaching storm. But when I saw neither clouds nor lightning, I
perceived that I must seek the origin of the sounds nearer, and that
they proceeded from the falling portions of rock.
The higher mountains to the left fade gradually more and more from
view; but the river Elvas spreads in such a manner, and divides into
so many branches, that one might mistake it for a lake with many
islands. It flows into the neighbouring sea, whose expanse becomes
visible after surmounting a few more small hills.
