For anyone interested in geology and travelling in South Shropshire, the geology
trails in Mortimer Forest are well worth a visit
The Trails lie to the west of Ludlow, in Shropshire, adjacent to a minor
road between Ludlow and Wigmore.
The best starting point for exploring the trails is the High Vinnalls car park (see
'Access and Safety' below). The entrance to the car park is shown left.
The rocks in the Ludlow area date from the Silurian Period, first defined by Sir
Roderick Murchison in 1835 and named after the Silures a celtic tribe that inhabited
the area of Wales where he conducted his studies. The rocks consist mostly of limestone
and shale and were deposited between 410 and 440 million years ago in a shallow
sea that was slowly closing and was to disappear completely by the end of the period.
The Silurian period is divided into four series, Llandovery (oldest), Wenlock, Ludlow and
Pridoli (youngest) and these trails have exposures in all except the Llandovery series.
Some of the sites are protected. There are two separate trails each with its own
excellent trail guide. Both guides give information on permitted collecting. To make
the most of these trails it is recommended that visitors equip themselves with a
copy of the guides, especially if their interest is in fossils rather rhan geology.
Maps
-
O.S. Landranger Series, 1:50,000, Map 137 (Ludlow and Wenlock Edge).
-
O.S. Explorer Series, 1:25,000, Map 203 (Ludlow).
-
British Geological Survey, 1:50,000 Series Maps, England and Wales Sheet 181, Ludlow
-
British Geological Survey, 1:25,000 Classical Areas Maps, No. 16 Leintwardine, Ludlow.
Return to Top
Trail Guides
-
The 'Mortimer Forest Geology Trail' (published in 2000 by Scenesetters for the
Forestry Commission)
This trail was created by the Nature Conservatory Council (now Natural England) and
the Forestry Commission in 1977 to recognise important research in the area in the
1960s that had redefined the Ludlow Series. The studies created two new geological
time stages that are now accepted worldwide, the Gorstian and the Ludfordian.
Copies of this trail guide may be obtained locally from the 'Secret Hills Discovery
Centre' at Craven Arms. The centre usually has a good range of local geology books,
guides and maps and also serves meals!
The trail guide describes 13 locations (identified on the ground as 'stops').
Except for locations 4 and 5, all are small quarries adjacent to a 4Km stretch of
road with no footpath and care must taken when walking between stops.
-
Geologists' Association Guide No. 27: The Geology of South Shropshire by
M. Allbutt, J. Moseley, C. Rayner & P. Toghill, 3rd Edition 2002.
Itinery 5: The Standard Ludlovian section of Mortimer Forest
gives detailed geological information for the area and includes a geology
trail, coincidentally also of 13 locations. Unlike the trail above this circular 10 Km trail
lies wholly within Mortimer Forest on roads free from traffic (except for occasional
Forestry Commission vehicles) and therefore can be safely followed either on foot
or by bicycle.
The pictures and descriptions below are for the shorter Forestry Commission trail.
Return to Top
Mortimer Forest Geology Trail
Turn left out of the car park and walk towards Wigmore.
Location 1: The first location is about 300 metres down the road on the right hand side. It
is a small quarry standing back from the road and may be identified by 'Mortimer
Forest Geological Trail Stop 1' on a wooden post in the grass verge. If you reach
the bottom of the slope and Pitch Cottage on your right you have come about 50
metres too far!
Here one can see alternating layers of limestone and mudstone from the Much Wenlock
Limestone Formation of the Wenlock Series. One may find a few Brachiopods but
fossils are scarce. The mudstone layers suggest repeated silty incursions that
are unsuitable habitat for filter feeding organisms such as corals.
Location 2: About 60 metres up the hill from stop 1 is another small quarry
that shows hard nodular limestone from the uppermost Much Wenlock Limestone
Formation. This is stop 2. Fossils are only freed from the nodular limestone by
natural weathering so fossils such as brachiopod shells are most likely to be seen
in the rock surface or washed out in the scree at the foot of the rock face.
Return to Top
A few metres above stop 2 may be seen the remains of an old lime kiln (see picture,
above right). This presumably processed limestone from the quarries to produce quicklime
for agricultural or building purposes.
Location 3: Location 3 is a few metres above location 2 on the other side of the
road. It is approached through a small plantation of Douglas Firs. The quarry is just
visible in the picture on the left, at the base of the distant trees beyond the figure in red.
Here two visible metres of hard nodular Wenlock limestone are over lain by well-bedded
siltstone of the lower Elton Formation, Ludlow Series.
Scientifically, this is probably the most important site on the trail.
The boundary between the Lower Elton bed siltstone and the Wenlock limestone is the
International Stratotype Boundary between the Wenlock Series and the Ludlow Series.
Do not hammer or scramble across this boundary on the quarry face
Location 4: Return to the Vinnalls car park. Take the wide forestry road
climbing up beyond the vehicle barrier. After about 250 metres, at the top of the
rise, another wide forestry track descends on the left. Follow this white-waymarked
forestry track for 700 metres. Just beyond a pond on the left, at the bottom of a
descent, a stream crosses the track. Here, to the left of the track, the Forestry
Commission has excavated a section of the stream bank. This is location 4 (there
is no visible post with the usual 'Stop n' label).
Academically, this site is valuable for graptolites that are important for the
international correlation of sites. However, it is also a popular hunting ground
for the Trilobite Dalmanites, though mostly only fragments are found.
One can see in the picture below, taken in May 2008, how the site has been plundered
by fossil hunters.
Pictures of the the first four exposures on the trail are shown below:-
Return to Top
 |
 |
Stop 1: Much Wenlock Limestone Formation - alternating layers of limestone and mudstone
|
Stop 2: Uppermost Much Wenlock Limestone Formation - hard nodular limestone
|
 |
 |
Stop 3: Much Wenlock Limestone Formation - Wenlock Series and Lower Elton Formation
|
Stop 4: Middle Elton Formation - Dark mudstones with lighter grey calcareous bands
|
Return to Top
Other Locations
The remaining locations, 5 to 13, are spread along 4Km of the road between High
Vinnalls car park and Ludford Corner. They cover the whole of the Ludlow Series and
the base of the Pridoli Series and are briefly summarised below:-
- Location 5: Upper Elton Formation
- Location 6: Lower Bringewood Formation
This site is at Gorsty which gives its name to the Gorstian Stage of the Ludlow Series.
- Location 7: Upper Bringewood Formation
- Location 8: Lower Leintwardine Formation
- Location 9: Lower Leintwardine Formation
- Location 10: Upper Leintwardine Formation
- Location 11: Upper Leintwardine Formation
- Location 12: Lower Whitcliffe Formation
- Location 13: Upper Whitcliffe Formation
Location 13, the world-famous Ludlow Bone Bed site, also carries a plaque to commemorate the 150th Anniversary of Murchison's Silurian System.
Access and Safety
From the town square in Ludlow head south, down hill, towards the river. Immediately
after crossing Ludford bridge, and before the rise, turn sharp right along a road
marked "Forestry Commission" and signposted 'Wigmore'.
After a short distance, at the top of a rise, the Forestry Commission Offices can
be seen on the left. After about 4Km (2.5 miles), turn left into the High Vinnalls
car park. The area is owned by the Forestry Commission, has free public access,
and is the starting point for both trails.
Notes:
-
All but two of the thirteen 'stops' described in the 'Mortimer Forest
Geology Trail' are excavations at the side of the road from Ludlow to Wigmore.
There is no footpath, so traffic poses a significant threat. Extreme care is needed
when walking between stops.
-
Except when expressly permitted, do not hammer on rockfaces. Some faces have been
undermined so that hammering can be dangerous. Also, some of the locations have
important structural features that can be destroyed by hammering.
Return to Top
|