would make but a small fraction of one of the days that make up the
periods with which the geologist deals. And the span of human life,
how it dwindles to a point in the face of the records of the rocks!
Doubtless the birth of some of the mountain-systems of the globe is
still going on, and we suspect it not; an elevation of one foot in a
century would lift up the Sierra or the Rocky Mountains in a
comparatively short geologic period.




II



It was the geologist that emboldened Tennyson to sing,--

"The hills are shadows and they flow
From form to form and nothing stands,
They melt like mists, the solid lands,
Like clouds they shape themselves and go."

But some hills flow much faster than others. Hills made up of the
latest or newest formations seem to take to themselves wings the
fastest.

The Archaean hills and mountains, how slowly they melt away! In the
Adirondacks, in northern New England, in the Highlands of the
Hudson, they still hold their heads high and have something of the
vigor of their prime.