428 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 23,
may formerly have extended quite across the ravine, and the missing
part may have been ploughed out by a glacier, or washed away by
the brook, or most probably removed by both. After a steep climb,
the floor of the dark and deep corry is reached. At its head there
are undoubted traces of local glacial action, though it is difficult to
say how far the moraine matter may not have been arranged under the
waters of the sea. In the middle, what looks like a small conical
hill from below rises up and forms the barrier of a swampy plateau
covered with rushes, which may be the site of a former small lake.
Between the conical mound and a moraine-like accumulation on the
N.W. side, there is a breach, which may mark the outlet of the supposed
small lake. On the S.E. side a great mass of fine debris runs
up the steep slope. On the N.W. side of the basin-shaped head of the
corry, the base of the steep cliffs of Skiddaw slate is concealed under
a series of chip and splinter deltas which point upwards to the vertical
gutters or "rakes" down which the detritus must have fallen
or been carried by rain. I mention this to show the difficulty of
distinguishing glacial moraine matter from common "screes" in
narrow mountain-recesses*.
On ascending the south side of the corry, and after walking over the brow of the hill, I descended towards Whicham through Black-Crag ravine, and was not surprised to find the mouth of this ravine choked up with drift containing large angular and rounded boulders. Along the base of the south-east escarpment of Blackcombe, and filling up the greater part of the length and breadth of Whicham Valley, there is an undulating broad terrace of drift, which near the hill-side rises up gradually and regularly, like an old tidal zone, and stretches into the ravines and cwms of the mountain. So far as can be seen, the lower part of this drift consists, at least in many places, of pinel. Thick deposits of sand and gravel apparently constitute its mass. In some places these deposits are capped with a reddish clay. The small brook which runs down from the semi-circular cwm behind Whicham parsonage has made a well-defined rut in the longitudinally level terrace, and exposed a section of alternating layers of loam, clay, sand, and rounded shingle, in some places resting on pinel. At a lower level, near Whicham Hall, a pit-section in a gently swelling knoll reveals thick masses of sand and gravel, the latter containing pebbles of granite, quartz (from the S.E. slope of Blackcombe?), &c., many of them extra-rounded; granite seems to predominate.
At the S.W. end of Whicham valley there are several sand and gravel hillocks; and Mr. Salmon, F.G.S., informs me that in this neighbourhood, some time ago, a bore-hole was stopped in about 300 feet of sand. Between the Whicham drift-terrace and Millom Hill, there is a flat depression, like a tidal channel, covered with recent deposits. Its bottom is only slightly elevated above the present sea-level. On the N.W. side of the low eminence called Holborn Hill (on which
- For remarks on the distinction between moraines and screes in the valleys
of the Coniston Fells, see the author's 'Scenery of England and Wales,' Excursion XX.
