Great Basin
This site marks the northern limit
of the Great Basin, a region some
six hundred miles long and up to five
hundred miles wide. It began forming
17 million years ago as the result of
regional uplift and east-west stretching by
geologic forces that continue today.
This stretching created a pattern of
north-trending mountain ranges
separated by broad flat valleys.
Precipitation that falls withing hte Great
Basin leaves only by evaporation, with no
outlet to the sea. During the ice ages, small
lakes in the valleys expanded to cover
thousands of square miles.
