Much of this
soil had crumbled down, but a great deal of it still retained the
form of castings." Dr. King dug up this plant, and was struck with
the thickness of the soil which must have recently accumulated over
the crown of the rhizoma, as shown by the length of the bleached
petioles, in comparison with those of other plants of the same
kind, where there had been no such accumulation. The earth thus
accumulated had no doubt been secured (as I have everywhere seen)
by the smaller roots of the plants. After describing this and
other analogous cases, Dr. King concludes: "I can have no doubt
that worms help greatly in the process of denudation."
Ledges of earth on steep hill-sides.--Little horizontal ledges, one
above another, have been observed on steep grassy slopes in many
parts of the world. The formation has been attributed to animals
travelling repeatedly along the slope in the same horizontal lines
while grazing, and that they do thus move and use the ledges is
certain; but Professor Henslow (a most careful observer) told Sir
J. Hooker that he was convinced that this was not the sole cause of
their formation. Sir J. Hooker saw such ledges on the Himalayan
and Atlas ranges, where there were no domesticated animals and not
many wild ones; but these latter would, it is probable, use the
ledges at night while grazing like our domesticated animals.
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