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Red Rock Pass

You are standing in the outlet of
ancient Lake Bonneville. A vast
prehistoric inland sea, of which
Salt Lake is a modern remnant.

Covering over 20,000 square miles when it
overflowed here about 14,500 years ago, its
winding shoreline would have stretched from here
to New Orleans if it were straightened out. This
pass was deepened considerably when Lake
Bonneville began to flow into Snake River. For
a time, a torrent several times larger than the
Amazon was discharged here. Finally, with
a hotter, drier climate that slowly emerged
about 8,000 years ago, Lake Bonneville
gradually disappeared.

Don't miss the rest of our virtual tour of Marsh Valley in 2897 images.