after completion. The apparent reasons were that the dam either had
failed or would fail to flood the area which he needed or desired
flooded. His endeavors are not always successful. About twenty years
ago, near Helena, Montana, a number of beaver made an audacious
attempt to dam the Missouri River. After long and persistent effort,
however, they gave it up. The beaver may be credited with errors,
failures, and successes. He has forethought. If a colony of beaver be
turned loose upon a three-mile tree-lined brook in the wilds and left
undisturbed for a season, or until they have had time to select a site
and locate themselves to best advantage, it is probable that the
location chosen will indicate that they have examined the entire
brook and then selected the best place.

As soon as the beaver's brush dam is completed, it begins to
accumulate trash and mud. In a little while, usually, it is covered
with a mass of soil, shrubs of willow begin to grow upon it, and after
a few years it is a strong, earthy, willow-covered dam. The dams vary
in length from a few feet to several hundred feet. I measured one on
the South Platte River that was eleven hundred feet long.

The influence of a beaver-dam is astounding. As soon as completed, it
becomes a highway for the folk of the wild. It is used day and night.
Mice and porcupines, bears and rabbits, lions and wolves, make a
bridge of it. From it, in the evening, the graceful deer cast their
reflections in the quiet pond. Over it dash pursuer and pursued; and
on it take place battles and courtships. It is often torn by hoof and
claw of animals locked in death-struggles, and often, very often, it
is stained with blood. Many a drama, picturesque, fierce, and wild, is
staged upon a beaver-dam.

An interesting and valuable book could be written concerning the
earth as modified and benefited by beaver action, and I have long
thought that the beaver deserved at least a chapter in Marsh's
masterly book, "The Earth as modified by Human Action." To "work like
a beaver" is an almost universal expression for energetic persistence,
but who realizes that the beaver has accomplished anything? Almost
unread of and unknown are his monumental works.

The instant a beaver-dam is completed, it has a decided influence on
the flow of the water, and especially on the quantity of sediment
which the passing water carries. The sediment, instead of going down
to fill the channel below, or to clog the