little guessed the origin of this geographical denomination that they
began by writing Augustura, and then Augusta.)

Angostura, the longitude and latitude of which I have already
indicated from astronomical observations, stands at the foot of a hill
of amphibolic schist* bare of vegetation. (* Hornblendschiefer.) The
streets are regular, and for the most part parallel with the course of
the river. Several of the houses are built on the bare rock; and here,
as at Carichana, and in many other parts of the missions, the action
of black and strong strata, when strongly heated by the rays of the
sun upon the atmosphere, is considered injurious to health. I think
the small pools of stagnant water (lagunas y anegadizos), which extend
behind the town in the direction of south-east, are more to be feared.
The houses of Angostura are lofty and convenient; they are for the
most part built of stone; which proves that the inhabitants have but
little dread of earthquakes. But unhappily this security is not
founded on induction from any precise data. It is true that the shore
of Nueva Andalusia sometimes undergoes very violent shocks, without
the commotion being propagated across the Llanos. The fatal
catastrophe of Cumana, on the 4th of February, 1797, was not felt at
Angostura; but in the great earthquake of 1766, which destroyed the
same city, the granitic soil of the two banks of the Orinoco was
agitated as far as the Raudales of Atures and Maypures. South of these
Raudales shocks are sometimes felt, which are confined to the basin of
the Upper Orinoco and the Rio Negro. They appear to depend on a
volcanic focus distant from that of the Caribbee Islands. We were told
by the missionaries at Javita and San Fernando de Atabapo that in 1798
violent earthquakes took place between the Guaviare and the Rio Negro,
which were not propagated on the north towards Maypures. We cannot be
sufficiently attentive to whatever relates to the simultaneity of the