They occur singly or in small groups on the north sides of the peaks of the High Sierra, sheltered beneath broad frosty shadows, in amphitheaters of their own making, where the snow, shooting down from the surrounding heights in avalanches, is most abundant.

Few sights are more striking than to see the huge mass of the amphitheater at Pola seeming to rise at once out of the land-locked sea.

In October of that year I discovered the Black Mountain Glacier in a shadowy amphitheater between Black and Rod Mountains, two of the peaks of the Merced group.

The main lateral moraines that extend from the jaws of the amphitheater into the Illilouette Basin are continued in straggling masses along the walls of the amphitheater, while separate boulders, hundreds of tons in weight, are left stranded here and there out in the middle of the channel.

At one place, perhaps a rod from the margin of the brook, was a sort of amphitheater among the trees, where nature had been prodigal with her colors, touching the woods in spots here and there with ocher, umber, and vermilion.

"Oh, we've got a real amphitheater for you, such as the Greeks used for the tragedies of Sophocles!"

They are mostly found in the upper branches of the cañons, and in the glacial amphitheaters around the peaks.

The light reflected from this sheet showed the dim outlines of a tiered amphitheater before which was a long table spread with strange-looking instruments, electrical machines and special apparatus for psychological experiments.