Wellington Heath to Oyster Hill LAGS Trail 18.10.2016
There had been heavy rain overnight but the skies had cleared and it was a bright sunny autumn
morning with a slight chill in the air. Ten members of the Landscape Appreciation Group (LAGS)
gathered together at the Farmers Arms in Wellington Heath.
Richard Edwards and Janet Parry were our guides for the morning walk. We got into a huddle
around Richard in the car park who outlined the route of the trail and explained the geological
setting.
We would walk from the village along the lanes and footpaths to the top of Oyster Hill with
spectacular panoramic views of the landscape. We would visit Loxter Quarry en route and loop
down around Oyster Hill, then retrace our steps to the car park. Finishing up with a pub lunch at the
Chase Inn Upper Colwall.
The geology, which underlies the stunning landscape of the area, is of the Upper Silurian marine
sequence of rocks. The hard Aymestry limestones form the hills with the softer Ludlow Shales
forming the valleys resulting in a typical ridge and vale topography. Narrow bands of Downton
Castle Sandstone are also present, representing the final episode of Silurian marine sedimentation in
this area.
The Ludlow Bone Bed marks the base of the Silurian Old Red Sandstone. The base of the Ludlow
Bone Bed is taken as the boundary between the Ludlow and the overlying Pridoli Series, and marks
the change from marine to alluvial and fluvial conditions. It is followed by the Downton Castle
Sandstone, which we will see on our walk, representing coastal beach and inter-tidal deposits.
As a point of particular interest to our group, Richard said, with a wry smile; 'lags' is a term used to
describe deposits in the Ludlow Bone bed. Ah! Fame at last we thought; LAGS mentioned in
despatches!
However, the reality was quite different: The deposit is a shallow water shelf concentrate and
represents inter-tidal skeletal 'lags' comprising fish scales and denticles.
The Ludlow Bone Bed is not seen here, but it has been recorded in Brockhill Coppice Quarry,
Mathon Road, near Malvern, which we visited on our Purleiu trail in December 2015.
The Silurian rocks have been tightly folded and faulted by late Carboniferous Variscan movements
around 300Ma. The East Malvern Fault was reactivated (reverse faulting) at this time, which also
caused the Precambrian rocks of British Camp (Herefordshire Beacon) to be thrust at a low angle
over Silurian strata. The British Camp is now out of line with the main axis of the Malvern Hills.
The Oyster Hill anticline is at the northern end of the more extensive Ledbury anticlinorium, which
runs almost parallel to the Malvern Hills, this is well illustrated on the geological map.
The Trail.
The underlying rocks, beneath our feet in the car park, belong to the Raglan Mudstone Formation
Rg, the sediments were laid down in continental conditions in the Pridoli sub-division of the Upper
Silurian Period.
We walked to Common Lane and crossed over to take a footpath on the right, finger posted 'Deer
Park Way' and 'Herefordshire Trail', we climbed up the steps leading to Ochre Hill.
Soon we were walking over a band of Downton Castle Sandstone DCS, which was evident from
the yellowish coloured deposits on the trackside. It was this natural yellow-orange pigment which
gave its name to the hill. Richard said that DCS contains hydrated iron oxide called goethite.
Goethite is the cement for the sandstone and it was named after Goethe the German literary
celebrity, which was most unusual.
Higher up the track on Ochre Hill, past houses on the right, we were on the Upper Ludlow Shales
ULu, according to the geological map. But there were exposures in the track which appeared to be
Downton Castle Sandstone DCS. We picked up several samples of the yellowish rock, some
contained fossils.
We paused to take in the view, looking down the valley eroded into the Raglan Mudstone
Formation with the Aymestry Limestone ridge of Frith Wood beyond. May Hill, with its clump of
trees, can be seen in the distance to the right of Frith Wood. May Hill Sandstone is the lowest part
of the Silurian sequence.
We continued on, taking the footpath north to Swallow Farm, through the horse paddock to join the
road to Loxter.
We stopped to examine the garden wall of a house up the road from Swallow Farm. Building stones
are a mixture of yellowish DCS and grey marine Silurian. There were some with Calcium
Carbonate crystals, and others contained nodules. Richard said that although nodules resembled
beach pebbles, they were formed by a completely different process. This was as a result of
Diagenetic changes taking place with a redistribution of the chemistry to form the nodules,
sometimes starting around a small inclusion to seed the process. We had seen abundant nodules in
the Wenlock limestone quarry wall at Hyde Farm on our Woolhope 1 trail
Building stones, a mixture of yellowish Downton Castle Sandstone and grey marine Silurian.
Nodular limestone building stones in the wall.
Calcium Carbonate crystals in the wall.
Further along the road we had a fine view down the valley with Ochre Hill on right and Frith Wood
on left, also a distant view of the Forest of Dean plateau with underlying rocks of the Carboniferous
Period.
Loxter Ashbed Quarry plunging anticline.
A little further along the road we climbed up a set steps on the left into a wooded area and
approached Loxter Ashbed Quarry, which has been cut into Aymestry limstone. Richard and Janet
pointed out some of the more interesting aspects of the quarry. Richard said the main feature was a
plunging anticline. The plunge was towards the viewer standing on the quarry floor.
Bentonite horizons could also be seen in the quarry walls. The bentonite clay bands in the quarry
face are much softer than the surrounding rocks and have eroded to form crevices. Volcanic ash
clouds during the Silurian Period, produced the bentonite, which was deposited on the sea floor,
preserved in the bentonite clay seams and then covered by later sediments.
Large blocks of limestone have slid down onto the quarry floor. We examined them is some detail
and concluded that they were not very fossiliferous, but we did find a small trilobite (approx.
25mm) on the large central block, there were also a few nodules. On one of the blocks, there
appeared to be some dessication cracks.
Trilobite approx. 25mm across.
A more detailed description of the quarry can be found at:http://ehtchampions.org.uk/ch/herefordshire-sites/loxter-ashbed-quarry/
We left the quarry and walked along the road towards the entrance to Hope End, we took the
Herefordshire Trail, and headed north to Oyster Hill. Janet told us that Hope End was the childhood
home of Elizabeth Barrett Browning and that her father bought Hope End in 1809, he had made his
fortune from Jamaican sugar plantations.
The footpath took us over alternate bands of Upper Ludlow Shales, Aymestry Limestone, Lower
Ludlow Shales and then back onto the Aymestry Limestone which caps Oyster Hill. We walked
through a parkland setting with specimen trees. Janet drew our attention to a pedunculate oak; was
it just one, or perhaps two joined at the hip, or maybe a bundle planting, who knows? The tree had
been struck by lightning, a scar was running all the way down one trunk. En route we could hear the
barking call of muntjac deer coming from Raycomb Wood.
David, making a strenuous effort to be first to reach the seat on the summit of Oyster Hill. West
Malvern to the right of the picture, Suckley Hills central with the Abberley Hills left on the distant
horizon.
We all climbed to the top of Oyster Hill and had a well earned coffee break.
LAGS on Oyster Hill. Appreciating the Landscape – on the lookout, in Meerkat Mode.
Looking out over the landscape from the top of Oyster Hill, Richard said that it was amazing how
many geological periods were represented in this area.
Panoramic view looking north from the summit of Oyster Hill.
Precambrian of the Malverns Complex out to the far east - right of picture. Cambrian and
Ordovician rocks are in the southern Malverns, but are not in this view. The Silurian limestones of
the wooded hills around Suckley. The Upper Silurian limestones here on Oyster Hill. The Raglan
Mudstone Formation forming the low-lying ground of the Herefordshire plain, with the Devonian
St Maughans Formation on the higher ground. The Devonian Old Red Sandstone of the Welsh
Black Mountains and Hay Bluff out on the far west. The Carboniferous coal measures around Clee
Hill and Mamble. The Permian Haffield Breccia tops Woodbury Hill near Great Witley. On our
way down the hill, the Jurassic of the Cotswolds could be seen beyond the Triassic Severn Valley.
We then walked north down the hill and looped around the lower slopes heading south along the
track on east side of Oyster Hill. Here we had fine views of the Malverns.
By the side of the track, under the roots of a silver birch tree was a yellowish subsoil, which we
assumed was formed on Downton Castle Sandstone DCS, there was a loose block lying on the
track, which turned out to be a piece of limestone. However, the detailed geological map shows
Raglan Mudstone Formation at this point.
A fly agaric toadstool was growing at the base of the birch tree. The fly agaric toadstool is very
poisonous and it has a mycorrhizal association with birch roots, it is nearly always found near birch
trees.
The symbiotic association of fungi with plant roots is widespread. Masses of fine threads, the
hyphae known collectively as mycelium, spread out over a large area in the soil, much greater than
the tree's roots. They explore new areas for minerals such as phosphate, which is essential for plant
growth. A sheath of fungus is formed around the tree's roots penetrating between the outer cells.
The fine infected tree roots become thicker and stubby and can be seen with the naked eye. The tree
exchanges surplus sugar to the fungus and it in return transports phosphate ions to the tree. This
symbiotic association evolved early in the evolution of land plants; primitive plant fossils have been
found complete with mychorizal fungi.
Spurge Laurel was seen on the trail; a good limestone indicator plant. Its common name is a
misnomer - being neither a spurge nor a laurel. Its scientific name is Daphne Laureola; it is a
calcicole... a plant which flourishes on lime-rich soils.
Heading for home, going back down the track above Hope End.
We retraced our steps back to the village of Wellington Heath, some of us then drove to Upper
Colwall and enjoyed a chat over a pint and a pub lunch at the Chase Inn.
Another brilliant trail, with a lot of interest in such a small area and with magnificent views over the
landscape.
Thanks, go once again, to Richard and Janet for their enthusiasm and research, for so eloquently
explaining the local geology and formation of the landscape, together with snippets of local
information. Thanks also to Moira for her helpful notes and photos.
Happy Trails.
Geological Maps.
Upper Silurian sequence of rocks.
Rg...Raglan Mudstone Formation. DCS...Downton Castle Sandstone. Ulu...Upper Ludlow Shales.
AL...Aymestry Limestone. Llu Lower Ludlow Shales.