This story is from the book Mysterious Archaeological Sites (available on Amazon.com) by George Mitrovic and takes place in Inyo County, California:
Near Death Valley: The Cowden Brothers in 1898 discovered the skeletal remains of a giant female (7.5 feet tall) at least 100,000 years old. Remains of camels and elephant-like creatures were also found.
In 1931 mummies were discovered by Dr. F. Bruce Russell. The men were eight to nine feet tall. These mummies were found in caverns. Hieroglyphics were found carved onto polished granite in another cavern which appeared to be some sort of ceremony room. This was in an area of Death Valley.
Local Indians believe that the area around and within Death Valley should be avoided at all costs and it is a place of the ghosts of the dead.
There are dozens if not hundred of stories about subterranean caverns which go for miles under Death Valley. There are legends of rooms filled with gold and treasure within the rooms of these caverns.