File:The Quarterly journal of the Geological Society of London (13204850764).jpg

96 T. M. READE ON THE DRIFT-BEDS OE THE
striation or planing on any of the numerous erratics I examined.
There is at Styperson, covering the rock, a red clay with erratic
stones ; but all over these hills, as far as Whaleybridge, drift is
generally absent.
Drift of the liivington Hills.
Perhaps the most interesting section of the Drift occurring
among the hills was that shown by the excavation for the puddle-
Pig. 12. — Turner's Trench, Yarrow Reservoir, 1872-75.
(Horizontal and vertical scales 220 feet to 1 inch.)
w. E.
A, A. Bottom, as exoavated. G. Gravel.
B, B. Shale excavated. H. Good blue clay, containing a few
C. Gravel and sand. • stones, sand-veins, and some gravel.
D, D. Loam. I. Peat and clay.
E. Boulders and gravel. J. Soil.
F. Gravel and sand.
wall of the Yarrow Eeservoir at Eivington*. The site of the
reservoir is to a large extent in the coal-shales, as proved hy the
tunnels and trenches. The river Yarrow runs from Allan's Bridge
into the Anglezark Eeservoir ; and the valley dammed up by the
embankments thrown across at two points to form the Yarrow
Eeservoir is a side valley, which the excavations proved was the
Preglacial valley of the Yarrow. This had been sufficiently filled
up with drift-deposits to divert the river up to the valley of the
Anglezark Eeservoir. The excavations for what was called Turner's
Trench (fig. 12) disclosed a gully in the solid rock 140 feet deep from
the surface, which, from the winding of its course, was intersected by
the same trench in two places, G and H. The bottom was in Mill-
stone Grit, which had a surface highly waterworn. The lower part
of the gully, Mr. Martin, the resident engineer, informed me, was
tilled up with gravel, sand, and large stones, the largest being
boulders of Millstone Grit. The upper part was of blue Boulder-
clay ; and throughout there were waterworn boulders and pebbles of
limestone, granite, porphyry, and greenstone. The excavation for
the puddle-wall of the Yarrow embankment intersected the same
gully at a higher level, and was filled up with loam, sand, veins
of gravel, and boulders (fig. 13).

• The Yarrow is a tributary of the river Douglas between the Mersey and
  

the BAbble. Not having devoted a special division to the basin of the Douglas,