ented to the Expedition by Senores Araria
and Roxas of Manila.

So far as our information and observations went, the whole of the
Philippine Islands are of similar geological formation. In some of
the islands the volcanic rock prevails, while in others coal and the
metalliferous deposits predominate. On some of them the coal-beds
form part of the cliffs along the shore; on others, copper is found
in a chlorite and talcose slate. The latter is more particularly
the case with Luzon, and the same formation extends to Mindoro. Much
iron occurs on the mountains. Thus among the (Upland) natives, who
are yet unsubdued by the Spaniards, and who inhabit these mountains,
it is found by them of so pure a quality that it is manufactured
into swords and cleavers. These are, occasionally, obtained by the
Spaniards in their excursions into the interior against these bands.

[Tufa.] The country around Manila is composed of tufa of a light gray
color, which being soft and easily worked, is employed as the common
building material in the city. It contains, sometimes, scoria and
pumice, in pieces of various sizes, besides, occasionally, impressions
of plants, with petrified woods. These are confined to recent species,
and include palms, etc.

This tufa forms one of the remarkable features of the volcanoes of the
Philippine Islands, showing a strong contrast between them and those of
the Pacific isles, which have ejected little else than lava and scoria.

Few portions of the globe seem to be so much the seat of internal
fires, or to exhibit the effects of volcanic action so strongly as
the Philippines. During our visit, it was not known that any of the
volcanoes were in action; but many of them were smoking, particularly
that in the district of Albay, called Isaroc. Its latest eruption
was in the year 1839; but this did little damage compared with
that of 1814, which covered several villages, and the country for a
great distance around, with ashes. This mountain is situated to the
south-east of Manila one hundred and fifty miles, and is said to be
a perfect cone, with a crater at its apex.

[Resources.] It does not appear that the islands are much affected
by earth-quakes, although some have occasionally occurred that have
done damage to the churches at Manila.

The coal which we have spoken of is deemed of value; it has a strong
resemblance to the bituminous coal of our own country, possesses a
bright lustre, and appears very free