This report describes the geology of BGS 1-10,000 Sheet SD 55 SE, part. of the
1:50,000 Sheets 59 (Lancaster) and 67 (Garstang). The area was first mapped by
R.C. Tiddemann on the scale of 1:10,560, and was published on the Primary
Series Sheets 91 NE and 91 SE in 1884. The present survey was carried out
between 1984 and 1986 by R.A. Hughes, E.W. Johnson, and A. Brandon, under the
supervision of Dr A.J. Wadge, Regional Geologist. The southern two thirds of
the area was mapped by R.A. ijughes, and the northern third (including the
important sections of the River Wyre and its tributaries) by Drs Brandon and
Johnson.
Approximately the southern third of the area is peat and heather covered
moorland, used only for sheep grazing and grouse shooting. Hawthornthwaite
Fell Top [5790 5148] is the highest point at 478 m, and lies on the watershed
of the Bowland Fells. To the south-west of here the land drains into the
headwaters of Langden Brook. To the north-west of the watershed the land
drains into the River Wyre. The remainder of the area is relatively
lower-lying and flat, and is used for pasture and for growing fodder crops.
The northern part of the area is incised by the westerly flowing River Wyre
and its tributaries. (The Marshaw Wyre and the Tarnbrook Wyre join at
Abbeystead to form the River Wyre).
The area contains the southern end of the Wyresdale tunnel, the geology of
which was described by Johnson (1981). The southern portal of the tunnel was
the site of a fatal explosion in May, 1984. The mapping of the northern third
of the sheet was a response to the demand for detailed geological information
for use in the ensuing public enquiry. The results of this work are presented
in Wilson, Brandon, and Johnson (1985). The only other work in the area is in
the extreme north-west of the sheet, which was mapped by Moseley (195