176 
GEOLOGY. 
on is sand-stone and flinty slate. In the neighbourhood of the Mission of San Juan is a 
sand-stone conglomerate, and on the road crossing from San Juan to the plain of Mon- 
terey, 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 mag- 
netic 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, to- 
wards 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. 
It continued a short time, but the shaking was so slight that it injured nothing. — C. 
SANDWICH ISLANDS. 
From what I had an opportunity of seeing on the Islands of Oahu (Woahoo), 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 inconsi- 
derable part of the plains around Oahu, where several flocks and herds are pastured. 
Where nearly on a level with the sea, its surface is often broken into excavations, which 
contain water, and maintain fish. It is often, however, raised above this level, as on the 
other side of the bay of 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. In the front of Dia- 
mond 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 water ; 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 first; a third layer of coral may have then 
accumulated above the second bed of volcanic matter. All this having taken place under 
