1872.] 43 [Kneeland. 
of the range,—causing by its gradual decay and tremendous force 
the present configuration of the country, with its streams, fertile 
meadows, and forests,—covering the Mariposa region, and carrying 
in its detritus the auriferous sand, so profitably worked in the beds of 
its rivers — extending over the present valleys of the Merced and 
Tuolumne rivers, even into the plains of the San Joaquin river and 
tke Stockton valley. 
- Mr. Muir’s researches, have, I think, shown that all of the higher 
basins were filled with ice, with a sheet so deep and universal, that 
only a few of the highest crests of the Sierra were large enough to 
separate it into individual glaciers—many of the highest, and the 
great domes having been flowed over and polished and rounded, like 
the boulders in a river. The enormous thickness and weight 
of this universal glacier will explain the marks of pressure above 
alluded to in the Cascade glacier; this, with the glaciers filling 
the valley, was but an insignificant fragment of the great whole. 
Glaciers poured into the valley by all its deeply covered cafions, and 
the great depression of the valley, we now behold with wonder and 
admiration, was hardly. more than a deep rut in the grand pathway 
of this magnificent ice stream, so high ‘did its thickness rise above the 
walls of the valley. All the rocks, and mountains, and domes,. and 
meadows of the upper Merced we can now readily believe received 
their peculiar forms and distribution through the agency of ice, and 
not of water; and that the domes and cafions and walls of the great 
valley itself have been fashioned by the same ice-action—the ice 
stream finding the valley previously existing, modifying, but not pro- 
ducing it, through the grand combination of its forces acting in a 
lone continued, uniform direction upon granite of the peculiar con- 
centric structure above alluded to. 
Among the most characteristic proofs of the existence of former 
slaciers here, are the innumerable lakes and meadows of the Sierra. 
The glacier receives boulders, and transports sand and dust from its 
polishing of the surrounding rocks, and on retreating builds up a ter- 
minal moraine, which forms a dam for the waters which are derived 
‘from the melting ice, at the same time by its irresistible grinding 
hollowing out a lake basin more or less deep. Gradually retiring, 
and finding a long period of rest under protecting rocks, it forms 
another moraine and dam like the first, but higher up, scooping out 
another basin and forming another lake. If the glacier then formed 
disappears two lakes are thus formed, one above the other, as are 
