File:The Quarterly journal of the Geological Society of London (12645828023).jpg

1862.. HARKNESS SKIDDAW SLATE SERIES. 131
however, on the east side of the high road, a small quarry in which a
felstone occurs, intermediate in character between a syenite and the
greenish rocks ; and a similar rock is also seen south-west from Wast-
dale Crag in the direction of Long Sleddale, where it is known under
the name of " flint." It is probably a mass of plutonic rock having
the same origin as the Wastdale Crag syenite, but possessing a less
crystalline nature in consequence of more rapid cooling from having
been in immediate contact with the greenish-grey rocks.
§ 6. The Skiddaw Slates of Black Comb.
The most southerly position occupied by the Skiddaw slates in
Cumberland or in Westmoreland is Black Comb, a mountain rising
abruptly to the height of 1919 feet, in the south-west of Cumber-
land ; it is surrounded on all sides, except the west, by the greenish-
grey rocks which succeed the Skiddaw slate series in the north of
England. On the west side, Black Comb is margined by a compa-
ratively low and flat tract of country, composed of the Trias sand-
stones extending southward from St. Bee's Head, and flanking on the
west side the Silurian rocks and their accompanying granites and
syenites.
To the south of Black Comb there is a flat tract of country which
separates this mountain from the greenish-grey craggy rocks of Mil-
lom, and in which no rocks are seen, the area being covered with till
and soil. Still further south, greenish -grey rocks occur, exhibiting
their usual broken outline, and presenting bold escarpments towards
the north — a feature generally accompanying their line of outcrop,
while on their dip they present commonly a less rugged aspect. To
the S.S.E., at Millom, these greenish-grey rocks pass under the
Coniston limestone and Coniston flags, which also dip S.S.E.
Fig. 6. — Section across Black Comb (5 miles).
N. Whicham. S.
, Stoneside-fell. Black Comb. (Till and soil.) Millom.
a a Fault. a b
a. Skiddaw Slate, b. Green slate, porphyries, &c.
On the north side of the Whicham valley (the flat interspace just
alluded to, where the southern flanks of Black Comb exhibit the
Skiddaw slates) the beds dip N.N.W.
Portions of the southern escarpments of this mountain have been
wrought for slate ; and among the debris of the quarries Graptolites
may be found, though from the Black Comb beds I have obtained
only one species, namely, Gh~aptolites Sagittarius. The position of the
strata here shows that they are very low down in the Skiddaw slate
series.