up and expelled?' They point out the fact, that
wherever such volcanoes exist, asphalt or petroleum is found hard
by. The mud volcanoes of Turbaco, in New Granada, famous from
Humboldt's description of them, lie in an asphaltic country. They
are much larger than those of Trinidad, the cones being, some of
them, twenty feet high. When Humboldt visited them in 1801, they
gave off hardly anything save nitrogen gas. But in the year 1850, a
'bituminous odour' had begun to be diffused; asphaltic oil swam on
the surface of the small openings; and the gas issuing from any of
the cones could be ignited. Dr. Daubeny found the mud-volcanoes of
Macaluba giving out bitumen, and bubbles of carbonic acid and
carburetted hydrogen. The mud-volcano of Saman, in the Western
Caucasus, gives off, with a continual stream of thick mud, ignited
gases, accompanied with mimic earthquakes like those of the Trinidad
Salses; and this out of a soil said to be full of bituminous
springs, and where (as in Trinidad) the tertiary strata carry veins
of asphalt, or are saturated with naphtha. At the famous sacred
Fire wells of Baku, in the Eastern Caucasus, the ejections of mud
and inflammable gas are so mixed with asphaltic products that
Eichwald says 'they should be rather called naphtha volcanoes than
mud-volcanoes, as the eruptions always terminate in a large emission
of naphtha.'

It is reasonable enough, then, to suppose a similar connection in
Trinidad. But whence come, either in Trinidad or at Turbaco, the
sea-salts and the iodine? Certainly not from the sea itself, which
is distant, in the case of the Trinidad Salses, from two to
seventeen miles. It must exist already in the strata below. And
the ejected pebbles, which are evidently sea-worn, must form part of
a tertiary sea-beach, covered by sands, and covering, perhaps, in
its turn, vegetable debris which, as it is converted into asphalt,
thrusts the pebbles up to the surface.

We had to hurry away from the strange place; for night was falling
fast, or rather ready to fall, as always here, in a moment, without
twilight, and we were scarce out of the forest before it was dark.
The wild game were already moving, and a deer crossed our line of
march, close before one of the horses. However, we were not
benighted; for the sun was hardly down ere the moon rose, bright and
full; and we floundered home through the mud, to start again next
morning in