Frequently they have in the middle of their depressed interior floors a peak, or a cluster of peaks.

Their inner and outer walls are seamed with ridges, and what look like gigantic streams of frozen lava surround them.

The resemblance that they bear to the craters of volcanoes is, at first sight, so striking that probably nobody would ever have thought of questioning the truth of the statement that they are such craters but for their incredible magnitude.

Many of them exceed fifty miles in diameter, and some of them sink two, three, four, and more miles below the loftiest points upon their walls! There is a chasm, 140 miles long and 70 broad, named Newton, situated about 200 miles from the south pole of the moon, whose floor lies 24,000 feet below the summit of a peak that towers just above it on the east! This abyss is so profound that the shadows of its enclosing precipices never entirely quit it, and the larger part of its bottom is buried in endless night.
One can not but shudder at the thought of standing on the broken walls of Newton, and gazing down into a cavity of such stupendous depth that if Chimborazo were thrown into it, the head of the mighty Andean peak would be thousands of feet beneath the observer.
A different example of the crater mountains of the moon is the celebrated Tycho, situated in latitude about 43 deg.

south, corresponding with the latitude of southern New Zealand on the earth.