suggested the modern aspect,
but required completion by the glaciers.

Geologically speaking, the glaciers were recent. There were several ice
invasions, produced probably by the same changes in climate which
occasioned the advances of the continental ice sheet east of the
Rockies. Matthes describes them as similar to the northern glaciers of
the Canadian Rockies of to-day. For unknown thousands of years the
Valley was filled by a glacier three or four thousand feet thick, and
the surrounding country was covered with tributary ice-fields. Only
Cloud's Rest, Half Dome, Sentinel Dome, and the crown of El Capitan
emerged above this ice. The glacier greatly widened and considerably
deepened the valley, turned its slopes into perpendiculars, and changed
its side cascades into waterfalls. When it receded it left Yosemite
Valley almost completed.

There followed a long period of conditions not unlike those of to-day.
Frosts chipped and scaled the granite surfaces, and rains carried away
the fragments. The valley bloomed with forests and wild flowers. Then
came other glaciers and other intervening periods. The last glacier
advanced only to the head of Bridal Veil Meadow. When it melted it left
a lake which filled the Valley from wall to wall, three hundred feet
deep. Finally the lake filled up with soil, brought down by the streams,
and made the floor of the present valley.

The centuries since have been a period of decoration and enrichment.
Frost and rain have done their perfect work. The incomparable valley is
complete.

III

THE PROPOSED ROOSEVELT NATIONAL PARK

INCLUDING THE PRESENT SEQUOIA NATIONAL PARK, WEST CENTRAL CALIFORNIA.
AREA, 1,600 SQUARE MILES

I

Where the lava billows of the Cascade Mountains end in northern
California the granite knobs of the Sierra begin. Sharply differentiated
in appearance and nature a few miles further in either direction, here
their terminals overlap, and so nearly merge that the southern end of
the one and the northern beginning of the other are not easily
distinguished by the untrained eye.

But southward the Sierra Nevada, the snowy saw-toothed range of the
Spaniards, the Sierra of modern American phrase, rapidly acquires the
bulk and towering height, the craggy cirqued summits and the snowy
shoulders which have made it celebrated. Gathering grandeur as it sweeps
southward close to the western boundary of California, its western
slopes slashed deep with canyons,