File:The Quarterly journal of the Geological Society of London (12512032653).jpg

216
PROCEEDINGS OF THE GEOLOGICAL SOCIETY.
grit ; while all tlie lower parts (commencing about a mile below the
village and to the west of the great transverse Craven fault) are com-
posed of the three groups of older rocks, above mentioned, which are
sometimes highly inclined and contorted. A great fault runs down
the valley of Dent, and a similar fault runs also down the valley of
Sedbergh, in consequence of which the Conistou grits (the most
striking of the older palaeozoic rocks of the neighbouring country) are
repeated at the north end of Middleton Fells, and at the south end of
Howgill Fells ; as may be illustrated by the accompanying section.
These faults and flexures do not at aU aflPect the Carboniferous series,
and evidently took place before the period of the Old-red-sandstone.
s.s.w.
S. end of Mid-
dleton Fells.
Fig. 1.
N.N.E.
1 . Coniston limestone and shale.
2. Conistou flags.
3. Coniston grits.
4. Ireleth slates (=Wenlock).
The great Craven fault, on the contrary, took place, for reasons
stated in former papers, after the Carboniferous rocks were complete,
and just before the period of the New-red-conglomerates. It crosses
the valley of Dent nearly at right angles to its direction, and pro-
duces a singular effect on the whole features of the neighbouring
country. In some places the carboniferous and the older palaeozoic
rocks are separated by deep valleys, excavated nearly on the line of
the great Craven fault, and these valleys are not unusually much
filled with drifted matter which conceals from view any junction of
the older with the newer Palaeozoic series. In other situations
(especially on both sides of the valley of Dent, and thence dovm Bar-
bondale) the two systems are seen to abut, one against the other ;
being simply divided by the broken, and often nearly vertical, masses
of carboniferous limestone which mark the range of the Craven fault.
In former papers I have described in sufficient detail the junction
at Helm's Gill on the north side of the valley of Dent, and I vdll
now shortly notice the corresponding phsenomena on the south side
of the valley where the two systems are seen (at the head of the pass
leading from Dent to Kirkby Lonsdale) to abut one against the other.
The general facts may be illustrated by the following, partly ideal,
section (Fig. 2).
There could be no reasonable doubt that the groups of this sec-
tion must be identical with those of Helm's Gill, which commence
with the Coniston limestone ; but the lowest beds (No. 1) are so ill
exposed, or so much displaced by ancient land-slips, that I had not,