if
)
'I ÍI
ii
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plaited rush, and the head of a stalk of Indian corn.
This fact, coupled with another, which will be mentioned,
proves I think the amount of eighty-five feet elevation since
man inhabited this part of Peru. On the coast of Patagonia
and La Plata, where perhaps the movements have
been slower, there is evidence, as we have seen, that several
mammalia have become extinct during a smaller change of
level. At Valparaiso, where there exist abundant proofs of
recent elevation to a greater altitude than in this part of
Peru, I can show that the greatest possible change during
the last 220 years, has not exceeded the small measure of
fifteen feet.
On the mainland in front of San Lorenzo, near Bellavista,
there is an extensive and level plain, at the height of about
a hundred feet. The section on the coast shows that the
lower part consists of alternating layers of sand and impure
clay, together with some gravel; and the surface, to the depth
of from three to six feet, of a reddish loam, containing a few
scattered sea-shells, and numerous small fragments of coarse
red earthenware. At first I was inclined to believe that this
superficial bed must have been deposited beneath the sea; but
I afterwards found in one spot, that it covered an artificial
floor of round stones. The conclusion which then seemed
most probable was, that at a period when the land stood at a
less height, there was a plain very similar to the one now
surrounding Callao, whioh being protected by a shingle beach,
is raised but very little above the level of the sea. On this
plain, with its clay beds, I imagine the Indians manufactured
their earthen v essels; and that, during some violent earthquake,
the sea broke over the beach and converted the plain
into a temporary lake, as happened in I7 l3 * around Callao.
The water would then deposit mud, containing fragments of
pottery from the kilns, and shells from the sea. This bed
with fossil earthenware occurring at about the same altitude
with the terrace on San Lorenzo, confirms the supposed
amount of elevation within the human period,
* F r e z ie r ’s Voyage.
CHAPTER XIX.
Isla n d s v o lcan ic— N um b e r o f c ra te rs— Leafless b u sh e s— C o lo n y a t d i a r i e s
Is la n d— J am e s I s la n d— S a lt- la k e in c ra te r— C h a r a c te r o f v e g e ta tio n—
O rn ith o lo g y , c u rio u s fin ch es— G r e a t to rto is e s , h a b its of, p a th s to th e
we lls— M a rin e liz a rd feed s o n s e a -w e e d— T e r r e s tr ia l sp e cie s , b u rrow in g
h a b its , h e rb iv o ro u s— Im p o r ta n c e o f r e p tile s in th e A r c h ip e la g o— F ew
a n d m in u te in se c ts— A m e ric a n ty p e o f o rg an iz a tio n— S p e c ie s co n fin ed to
c e rta in islan d s— T am en e s s o f b ird s— F a lk la n d Is la n d s— F e a r o f m an
a n a c q u ir e d in s tin c t.
G A L A P A G O S A R C H I P E L A G O .
S e p t e m b e r 1 5 t h .'—The Beagle arrived at the southernmost
of the Galapagos islands. This archipelago consists
of ten principal islands, of which five much exceed the others
in size. They are situated under the equatorial line, and
between five and six hundred miles to the westward of the
coast of America. The constitution of the whole is volcanic.
With the exception of some ejected fragments of granite,
which have been most curiously glazed and altered liy the
heat, every part consists of lava, or of sandstone resulting
from the attrition of such materials. The higher islands,
(which attain an elevation of three, and even four thousand
feet) generally have one or more principal craters towards
their centre, and on their flanks smaller orifices. I have no
exact data from which to calculate, but I do not hesitate to
affirm, that there must he, in all the islands of the archipelago,
at least two thousand craters. These are of two
kinds ; one, as in ordinary cases, consisting of scorioe and
lava, the other of finely-stratified volcanic sandstone. The
latter iu most instances have a form beautifully symmetrical :
their origin is due to the ejection of mud,—that is, fine volcanic
ashes and water,—without any lava.
Considering that these islands are placed directly under
the equator, the climate is far from being excessively hot ; a