ridge from Crook Peak to Axbridge Hill is formed of Carboniferous Limestone, which
forms the southerly dipping limb of the Blackdown pericline. The
northern side of the ridge forms a scarp of Black Rock Limestone,
overlooking the Lox Yeo valley, which is infilled with Dolomitic
Conglomerate overlying the Portishead Formation.
The southern side of the ridge is indented by several small valleys,
many of which follow the lines of earlier Triassic valleys. Modern
erosion has preferentially removed the softer Triassic rocks, in
effect recreating the Triassic landscape.
The Black Rock Limestone is well exposed in a small quarry on the
northern side of Crook Peak, in the railway cutting at Shute Shelve
and in the many small cliffs on the northern side of the ridge. The
overlying Burrington Oolite can be seen in the crags at the top of
Crook Peak and in the small disused quarries at the foot of the ridge
south of Compton Bishop. The Clifton Down Limestone outcrops in the
disused quarry at Cross and in the road cutting at the western end
of the Axbridge bypass.
Cross-section of Axbridge Hill (click to enlarge view).
Aerial view of Crook Peak and Axbridge (click to enlarge view).
The area includes a very wide range of different habitats including
extensive areas of limestone grassland on Crook Peak and Wavering
Down, ancient woodland habitats in Kings Wood, and more typical woodland
habitats in Rose Wood and Cheddar Wood. The south-facing slopes of
Axbridge Hill and Wavering Down are superb wildlife habitats. The
rocky bluffs, limestone screes and thin soils support an exceptionally
rich flora including a number of rarities such as honewort, somerset
hair-grass, Cheddar pink and several rare lichens. The combination
of rich vegetation and warm, south-facing aspect is also highly attractive
to butterflies. In some areas acidic loessic soils occur, which supports
dwarf shrub heath with bracken, gorse and heather and bell heather.
The hillside above Axbridge is dotted with numerous ochre
pits, which were worked as late as the 1920s. When the mines
were active, a tramway and cableway were constructed from Axbridge
railway station up the hill to several ochre pits which are still
accessible. The ochre infills pockets in the Carboniferous Limestone.
Fragments of yellow and red ochre, which consists of various iron
oxide minerals including limonite, goethite and hematite can be found
scattered around the area.
One of the many small pits hidden within Rose Wood is the entrance
to Shute Shelve Cavern. Discovered in 1994 by local cavers, the small
entrance opens up into a large passage up to 20 m wide. Part of the
cave had been entered by the miners and it could be the 'Lost Cave
of Axbridge' rumoured to exist on the hill.
The summit of Callow Hill is dominated by Callow
Rock Quarry. This quarry works the Burrington Oolite
which is used in the adjacent concrete block-works, and supplies
mainly a local market. Several other old quarries occur in Shipham
Gorge, but are now disused.