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RESIDENCE AT TARAPOTO 53
cargueros. Our first day's journey, of about 15
l
miles, brought us to Lamas a town of 6000
inhabitants, near the top of a conical hill, that
reminded me of similarly situated towns and villages
in Valencia, as they are depicted in Cavanilles'
History of that province of Old Spain.
The Hill of Lamas is plainly volcanic, although
there is no evidence of eruptions in the shape of
lava, or any obvious crater, unless certain small
lakes without inlet or outlet a little below the
summit may be considered such. The fertile soil
which covers its flanks, and yields abundant crops
of every esculent that will bear the climate, especially
of the indispensable poroto (a kind of
kidney-bean), consists almost entirely of decom-
posed shales of divers colours sulphur-yellow,
vermilion, purple, slate-blue, and black. These
shales belong to the Triassic series near Tarapoto
I found ammonites of immense size in them and
have apparently been broken up by the protrusion
of a columnar jointed trap-rock, which is here and
there exposed in the shape of a sloping floor,
divided with much regularity into squares, rather
less than a foot on the side, and called by the
natives ladrillos or bricks. The slope of the
floors is always towards the apex of the mountain,
and is inclined to the horizon at from 10 to 30.
the shales there has been a soft white
Overlying
sandstone, in thick strata, great part
of which has
been decomposed and carried into the hollows, and
even into the plain below, by the torrential rains
leaving only a few scattered blocks of more tenacious
material than the rest.
1 Lamas: lat. 6 5' S. ; alt. (convent) 25(14 I-:, ft., (hill-top) 2849 fl