mark is reached. But because the melting does not go on
rapidly over all the fountains, high and low, simultaneously, and the
melted snow is not reinforced at this time of year by rain, the spring
floods are seldom very violent or destructive. The thousand falls,
however, and the cascades in the canons are then in full bloom, and sing
songs from one end of the range to the other. Of course the snow on the
lower tributaries of the rivers is first melted, then that on the higher
fountains most exposed to sunshine, and about a month later the cooler,
shadowy fountains send down their treasures, thus allowing the main
trunk streams nearly six weeks to get their waters hurried through the
foot-hills and across the lowlands to the sea. Therefore very violent
spring floods are avoided, and will be as long as the shading,
restraining forests last. The rivers of the north half of the range are
still less subject to sudden floods, because their upper fountains in
great part lie protected from the changes of the weather beneath thick
folds of lava, just as many of the rivers of Alaska lie beneath folds of
ice, coming to the light farther down the range in large springs, while
those of the high Sierra lie on the surface of solid granite, exposed to
every change of temperature. More than ninety per cent. of the water
derived from the snow and ice of Mount Shasta is at once absorbed and
drained away beneath the porous lava folds of the mountain, where
mumbling and groping in the dark they at length find larger fissures and
tunnel-like caves from which they emerge, filtered and cool, in the form
of large springs, some of them so large they give birth to rivers that
set out on their journeys beneath the sun without any visible
intermediate period of childhood. Thus the Shasta River issues from a
large lake-like spring in Shasta Valley, and about two thirds of the
volume of the McCloud River gushes forth suddenly from the face of a
lava bluff in a roaring spring seventy-five yards wide.

These spring rivers of the north are of course shorter than those of the
south whose tributaries extend up to the tops of the mountains. Fall
River, an important tributary of the Pitt or Upper Sacramento, is only
about ten miles long, and is all falls, cascades, and springs from its
head to its confluence with the Pitt. Bountiful springs, charmingly
embowered, issue from the rocks at one end of it, a snowy fall a hundred
and eighty feet high thunders at