nto parallel runnels, that
gradually widened into these hollow grooves--had sunk into the angle of
inclination at which the disintegrating agents ceased to operate, and
the green sward covered all up. You must be studying these peculiarities
of aspect more than ever you studied them before. There is a time coming
when the connoisseur will as rigidly demand the specific character of
the various geologic rocks and deposits in your hills, _scaurs_, and
precipices, as he now demands specific character in your shrubs and
trees.

It is worthy the notice of the young geologist, who has just set himself
to study the various effects produced on the surface of a country by the
deposits which lie under it, that for about a quarter of a mile or so,
the base of the escarpment here is bordered by a line of bogs, that bear
in the driest weather their mantling of green. They are fed with a
perennial supply of water, by a range of deep-seated springs, that come
bursting out from under the boulder-clay; and one of their number, which
bears I know not why, the name of Samuel's Well, and yields its equable
flow at an equable temperature, summer and winter, into a stone trough
by the way-side, is not a little prized by the town's-people, and the
seamen that cast anchor in the opposite roadstead, for the lightness and
purity of its water. What is specially worthy of notice in the case is,
the very definite beginning and ending of the chain of bogs. All is dry
at the base of the escarpment, up to the point at which they commence;
and then all is equally dry at the point at which they terminate. And of
exactly the same extent,--beginning where the bogs begin, and ending
where they end,--we may trace an ancient stratum of pure sand,--of
considerable thickness, intercalated between the base of the clay and
the superior surface of the Old Red Sandstone. It is through this
permeable sand that the profoundly seated springs find their way to the
surface,--for the clay is impermeable; and where it comes in contact
with the rock on either side of the arenaceous stratum, the bogs cease.
The chain of green bogs is a consequence of the stratum of permeable
sand. I have in vain sought this ancient layer of sand,--decidedly of
the same era with the argillaceous bed which overlies it,--for aught
organic. A single shell, so unequivocally of the period of the
boulder-clay as to occur at the base of the deposit, would be worth, I
have said, whole drawerfuls of