Our collections, however,
contain pieces of trunks of palm-trees, enclosed and penetrated by
the very liquid lava of the isle of Bourbon.
Though Teneriffe belongs to a group of islands of considerable
extent, the Peak exhibits nevertheless all the characteristics of a
mountain rising on a solitary islet. The lead finds no bottom at a
little distance from the ports of Santa Cruz, Orotava, and
Garachico: in this respect it is like St. Helena. The ocean, as
well as the continents, has its mountains and its plains; and, if
we except the Andes, volcanic cones are formed everywhere in the
lower regions of the globe.
As the Peak rises amid a system of basalts and old lava, and as the
whole part which is visible above the surface of the waters
exhibits burnt substances, it has been supposed that this immense
pyramid is the effect of a progressive accumulation of lavas; or
that it contains in its centre a nucleus of primitive rocks. Both
of these suppositions appear to me ill-founded. I think there is as
little probability that mountains of granite, gneiss, or primitive
calcareous stone have existed where we now see the tops of the
Peak, of Vesuvius, and of Etna, as in the plains where almost in
our own time has been formed the volcano of Jorullo, which is more
than a third of the height of Vesuvius.
