CALIFORNIA. Sat 
mineral of which it is composed, so that a crust is formed some- 
times as much as half an inch thick. This crust is more durable 
than the body of the rock, and, as the granite weathers, it scales 
off, sometimes in large flakes with a highly-polished surface on one 
side, 
Mono Lake, one of the most remarkable in the State, fourteen 
miles wide from east to west, and nine long from north to south, 
had many well-defined terraces around its shores, one very distinct, 
being 385 feet above the water. The water is of high specific 
gravity, and intensely saline, containing borax, common salt, and 
carbonate of soda. 
Several islands are composed of volcanic material, hard black 
basalt, scorie, cinders, and stratified ashes. Steam and hot gases 
escaping from the orifices of many of the fumaroles make con- 
siderable noise, and leave thin incrustations which appear to consist — 
of chloride of iron. 
Myriads of sea gulls resort to this lake to breed during the 
summer; but the water is destitute of life, with the exception of 
the larvee of a small fly, which occurs in immense quantities, and, 
when dried, furnishes food to the Indians of the region. 
A chain of volcanic cones stretches south from Mono Lake in a 
north and south direction. Obsidian and pumice abound on the 
top and sides, and extend over the plain beneath. 
At the summit, and within the cone of one of these, several 
boulders of rose-coloured granite were observed mixed with the 
voleanic ashes, pumice, and other erupted materials. As the 
cones preserve their form, glacial action could hardly have brought 
them here without crushing the walls which remain perfect; the 
most likely supposition seems to be that they were ejected from the 
craters, having been torn from the underlying granite through 
which the eruptive matter has forced its way, as is seen throughout 
the Sierras, 
