OLDEST ROCKS OF
YOSEMITE
REGION
THESE WRINKLED AND BROKEN STRATA ARE THE
OLDEST FORMATIONS OF THE YOSEMITE REGION.
THEY WERE FORMED IN THE SEA AS DEPOSITS
OF MUD, SAND, AND OTHER MATERIALS FOLDING,
BREAKING, AND CHANGE IN TEXTURE RESULTED
FROM MOVEMENTS WHICH PRODUCED THE ORIGINAL
SIERRA RANGE, NOW LARGELY WORN AWAY
IN FORMING THOSE ANCIENT MOUNTAINS, IMMENSE
MASSES OF MELTED ROCK MOVED UPWARD INTO THE
EARTH'S CRUST BELOW THE DISTURBED AREA THIS
MOLTEN MATERIAL COOLED TO FORM GRANITE THE
GRANITE MAY BE SEEN IN MERCED CANYON IMMEDI
ATELY ABOVE EL PORTAL AND IN YOSEMITE VALLEY
ACROSS THE CANYON FROM THIS POINT THE RIVER HAS CUT AND
POLISHED THESE SOCKS AUSING THE INTENSELY FOLDED LAYERS TO
STAND OUT IN BOLD RELIEF
Geological Marker
On the All Year Highway
The scenic Route along the Merced River
Mariposa to Yosemite National Park
California
F-7715