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176 G EOLOGY.
on is sand-stone and fiinty slate. In the neighbourhood of the Mission of San Ju an is a
sand-stone conglomerate, and on the road crossing from San Ju an to the plain of Monterey,
is sand-stone. From the interior of the range between San Juan and Monterey,
the inhabitants of Las Animas had brought compact basalt, containing particles of magnetic
iron ore, which encouraged the delusive hope of rich mines. A few miles down the
river Paxaros, from where the road to San Juan crosses it, there are thermal springs, and
sulphur in their neighbourhood. On the Santa Cruz side, near the Mission, there is
said to be coal, but it has never been mined. Along the east shore of the bay of San
Francisco, for thirty-five miles east-south-east, from beyond the Island of Molate, towards
San Josef and Santa Clara, the harbour is bounded generally by low alluvial soil,
and only in a few places do low and rocky cliffs protrude. Near the Mission of San Josef
there are some hot springs in the plain, surrounded by a verdant covering. Earthquakes
are rather common, and one in 1806 so shook the building of the Mission of Santa Clara,
that a new one was obliged to be erected. A few years ago, a boat belonging to a whale
ship, when lying in several feet water, was suddenly thrown on the beach and left dry,
and a vessel in the bay of Monterey was suddenly and severely tossed about by the sea,
and the shock was felt on shore at the same time. At ten o’clock on the 26th December,
1827, a slight shock was felt at San Josef. The shocks are said to come along the coast
from the northward, and when they are also felt at Monterey it is some minutes later.
One was perceived at the Presidio of San Francisco in the month of April, 1827.
I t continued a short time, but the shaking was so slight that it injured nothing.—C.
SA N DW IC H IS LA N D S .
From what I had an opportunity of seeing on the Islands of Oahu (VToaboo), and
Nihau (Oneehow), and from what I was informed respecting the rest, I consider the
whole group to be volcanic and coralline. The latter formation constitutes no inconsiderable
part of the plains around Oabu, where several flocks and herds are pastured.
Where nearly on a level with the sea, its surface is often broken into excavations, whicii
contain water, and maintain fish. I t is often, however, raised above this level, as on the
other side of th eb ay o f Waititi. Ponds at a considerable distance inland communicate by
subterraneous passages with the ocean, and are affected by its flux and reflux. From
some of these, and one in particular, considerable quantities of salt are procured.
The height of Elizabeth Island can only be plausibly accounted for by supposing that
it has been bodily carried upwards by some volcanic power below. Tn the front of D iamond
Island, as it looks to the south, and to the sea, I observed two or three different
thin strata of coralline formation, lying horizontally about ten feet above each other, and
alternating with strata of volcanic stones and tufaceous sand. The whole must have been
at one period under w a te r; the lower stratum of coral may have been covered with a
thick bed of volcanic matter from an eruption of the extinct volcano of Diamond Hill,
several years may have passed before any more materials were ejected, meantime the
coralline formation may have gone on, until a second eruption covered it with a second
deposit of volcanic matter similar to the firs t; a third layer of coral may have then
accumulated above the second bed of volcanic matter. All this having taken place under
water, it is necessary to presume a bodily elevation of the whole, to place it in its
present conspicuous situation. Diamond Hill has every appearance of having been a
volcano, and it may have been raised from under the waters of the ocean a t a period
posterior to the rest of the island, as the land which joins it to the general range of mountains,
if not coral, is on a level with the coral to the east and to the west. A lake is
said to occupy the closed crater. Tradition relates, that several years back the sea
rose so high as to inundate a great part of the islands, and sweep off a great number of
inhabitants. Within the memory of living residents, they say a shower of black stones
fell close to the town of Honoruru.
I saw but very few specimens of the rocks. The mitta is generally a sort of greyish
or reddish porphyry, or black basalt. The stone chisel, and no doubt also the adze, are
a compact basalt. The native mirror is made of the same stone, and wetted when it is
to be used. Pumice and recent lava I had an opportunity of procuriug. The nodules
of zeolite are rather rare.
A very good general description of the volcano of Kirauca, a t the foot of Mauna
Roa, is contained in the Missionary Tour round Hawaii. I t appears to be a very extensive
sheet of boiling lava, having small cones of black rock interspersed in the vast
basin, and the whole covered with fiery waves. I t is probably larger than any of the commonly
known craters. Tradition has appointed the goddess P e le to preside over it.
IS L A N D OF G R EA T LOO CHOO.
The island presents a surface diversified with rounded eminences of small elevation,
and gentle declivities, for the most part in a state of cultivation. The middle ridges
and rounded hummocks are covered with wood, generally the Pinus Massoniana, with
the Cycas, or with a short and unproductive vegetation. In the ridges of these hummocks
are extensive ranges of tombs, excavated in the faces of the rocks, of several feet
in height. Where they approach the sea, these rocks are much undermined ; in the
harbour of Napakiang, they are very remarkable in this respect; and one has been
named Capstan Rock, from its flattened top being circularly undermined so as to give it
that form. I t is washed by the waves, and appears to owe its shape to their influence.
This hollowing out is not confined to those cliffs which are at the water’s ed g e ; it is
also very conspicuous to the south of Abbey Point, where a long beach, now partly converted
into a verdant flat, separates the sea from the rocks. These cliffs and precipices,
whether in the interior or on the coast, are composed of a coral lime-stone, either compact
or cellular, most commonly the latter, and presenting a very rugged surface. The
principal of those coral ridges extends from the coast to the north-west of Nawha (or
Napakiang) inland, and eastward or south-east to tbe town of Ishoomee, and an enclosed
building called Eepang-kwang, or the Palace of the King, according to Captain Hall.
At this place it attains its greatest height, about 800 feet above the level of the sea.
This appeared to us to be the highest part of the island. The other ridges and hummocks
are seldom elevated above half this height. Some of them, particularly to the
south-east of Abbey Point, are formed of a bluish marl, in some places approaching to