File:The Quarterly journal of the Geological Society of London (13860422694).jpg

PROF. C. LAPWORTH ON THE GIRVAN SUCCESSION.
615
interpreted ascending succession is displayed in the heights of
Quarrel Hill, Mulloch Hill, and Glenshalloch.
(a) Sections of the Inner Zones of Strata of the Quarrel-Hill Anticlinal.
(i) Barren Flagstone-series of Farden and Quarrel Hill.
In the centre of this dome-like area, and consequently occupying
the lowest horizon in the vertical succession of its rock-formations,
we find a series of barren flagstones and shales, identical, both in their
petrological characters and in the few organic remains they yield,
with our Barren or Shalloch Flagstones of Shalloch and Penwhapple —
thus presenting, at the very commencement of our study of the rocks
of this area, a clear and definite horizon of reference for the surround-
ing and concentric zones of strata of which this northern inlier of
Lower Palaeozoic rocks is composed.
These flagstones occupy an ellipsoidal area about a mile in length,
ranging from the loop-fault which bounds the igneous rocks of
Craighead Hill, through the wooded grounds of Balweary, into the
grassy slopes of Quarrel Hill. Over much of the area they occupy
they are hidden from sight by superficial deposits; but excellent
sections are laid bare in the burns which descend the ridge in the
direction of Craighead fault, near Kildrummie. The most satisfac-
tory of these exposures is that seen on the banks of the small stream
to the west of Quarrel Hill, where the section figured below is dis-
played from end to end (fig. 20).
Fig. 20. — Section of the Barren Flagstone Beds of Quarrel Hill.
S.E.
Brachiopoda— Mcristella angustifroiu
t. ' i
.LOC/i H/Ll
J3n:x.-s
x. Carboniferous rocks, not exposed.
Ca. Mullock-Hill Beds.
2. Calcareous flagstones, with
Atrypa seotica, &c.
1. Mulloch-Hill conglomerate.
Bd. Drummuck or Trinacleus-be&s

—
Thin flags and shattered niudstones, with Bellerophon bilobatus &c.
Be. Barren Flagstones.
(4). Grrey flagstones and shales, weathering buff or yellow.
(3). Green shales and mudstones.
(2). Alternations of thin-bedded green flags and mudstones.
(1). Thin-bedded flaggy beds, with partings of green and grey mudstones-
Nematolites Grayii and Diplograptus truncatus.
ff.