1884.] “ Hydraulic Mining " in California. 443 
it has already been removed, by the continuous natural 
adtion of centuries, to form there, as elsewhere, the plains 
and piaiiies of the earth, burying and diverting by the mu- 
tation the ancient river system, whose sources of supply 
weie consequently extinguished by the removal of these 
altitudes. These denudations and subsequent depositions 
have been caused by alternations of temperature and com- 
bined aftion of air, water, and time since the creation of the 
world ; and powerful demonstrations of these transforma- 
tions instruct us in all directions, if we care to observe them. 
Thus in Little Cottonwood ” ravine, in the Wasatch range 
of mountains in Utah Territory, lie isolated, in the centre of 
the valley, huge masses of metamorphic granite, some 
blocks of which weigh individually thousands of tons, and 
weie dislodged from the hills — which on either side are of 
limestone formation — with no visible granite in them, having 
been undermined by the removal of their pulverised basis 
by denudation, and which is the material now forming the 
table-lands, the foundation of Salt Lake city. The blocks 
of granite, having alone resisted the atmosperic changes, 
were precipitated into the valley beneath, and the Mormons 
are now constructing their cathedral church from these 
granitic remains. 
1 he melting of the snow which formerly capped all these 
ranges of mountains furnished the water that once flowed in 
the extinguished channels of ancient rivers, and whose now 
diverted waters were also the powerful agent to assist in 
causing these marvellous alternations ; and by the means of 
hydraulic mining we can advance our feeble knowledge on 
the subject. These mighty changes have gradually been ac- 
complished, and the accumulated denudations of the mineral 
zones have defended themselves by stratas of crystallised 
silicates of quartz of various thicknesses, and thus in places 
beneath such system of defence, or by their own concretion, 
have preserved in many localities a thickness of from 500 to 
600 feet of conglomerate ; but without this necessary ce- 
mentation its further removal is very certain when again 
attacked by water. And an example of this continuous 
process is very observable in “ Death Valley,” Lower Cali- 
fornia, where a width of about 100 miles has been filled up 
from the hills to the gulf of same name, invading and occu- 
pying its former bed ; and this activity is still proceeding, 
and a temporary formation of table-land above it is in course 
of removal, although already overgrown with forest trees, 
which are toppling over the side which is being attacked. 
But eternal snow now only covers a small portion of these 
2G2 
