Environmental Engineering Reference
In-Depth Information
it across Swansea Bay to Swansea and Briton Ferry. The
Swansea Guide
of 1851 notes that 'a valuable
vein of iron ore … has been worked, much to the disfigurement of this romantic spot.' A narrow trench,
known as 'the Cut', was left across the hill. It was almost completely backfilled with rock hollowed out
of Mumbles Hill when an underground sewage works was constructed in the 1930s. The remaining part
of the trench can be clearly seen today from the viewpoint at the top of the hill, near the coastguard radio
mast.
Rhossili Downisarather exceptional feature; unlike theotherhighpointsonthepeninsula theaxisof
theanticlineisalignednorth-southratherthaneast-west.Thisisbecausetherocksthatmakeuptheridge
were rotated along the line of the Llangennith fault. The west-facing scarp of Rhossili Down is formed
along the Broughton fault and the Port-Eynon thrust lies to the south. It is therefore surrounded on three
sides by faults, the steep slopes on the west, south and east being fault faces.
This then is the sequence of the Gower rocks and the forces that have shaped them into the peninsula.
Because it is the oldest rocks, the Old Red Sandstone, that are now exposed on high ground at Cefn Bryn,
Llanmadoc Hill and Rhossili Down it is clear that in these places the combined thickness of the Carbon-
iferous Limestone, Millstone Grit and Coal Measures has been removed over the last 280 million years.
The action of wind and water, assisted by plant roots, chemical breakdown and glaciers, has taken away
an incredible 4,600 metres of rock.
