Fern mutation

Common male-fernDryopteris filix-mas . Bipinnate; growth form: shuttlecock; scales are pale brown; sori not yet visible. There is an interesting mutation on the ends of the pinna, a similar phenomenon, known as fasciation, has also been noted to occur on Hart’s tongue fern. Habitat is my back garden in a partially shaded, sheltered spot next to the shed. Location: NE Somerset. 

Swan Mine (also known as Kingsdown Quarry)

NGR ST 81019, 67022

With members of the Axbridge Caving Group (ACG), underground about 2 hours.

The entrance to Swan Mine

Entrance located opposite the Swan Inn public house. There were originally three entrances. A small but interesting stone mine (Freestone) where extraction is believed to have started in the late 18th century and ended in 1932. It is thought to be the last operational stone mine in the UK to remove stone using horse and carts – wheel ruts are a predominant feature throughout the mine passages, a few hoof-prints still remain. A major attraction of the mine is the numerous artefacts that are still in-situ including a well-preserved crane, a second crane has been crushed under a rockfall, a fine carved stone trough, and a variety of other industrial paraphernalia.

There are abundant historic markings throughout the mine related to quarrying activities sadly many markings have been defaced by unnecessary graffiti and, in places, calcite deposition.

A mixed panel of markings including quarrying related, a possible depiction of ‘Hitler’ and a poorly placed spray paint direction arrow!

Mostly easy walking although there are places where scrambling over rocks and negotiating lower sections is required. An interesting couple of hours spent wandering around and taking photographs. Some decent fossils were also noted, in particular, corals perhaps evidence for Jurassic reefs.   

Coral group
A stop to admire some hoof-prints
A dead end!


Foliose lichen. Image taken 01/01/2024

Lichens are a stable, mutualistic association between a fungus (= mycobiont), the dominant species in the association, and a green alga or cyanobacteria (= photobiont). The mycobiont provides the photobiont with a safe place to live and grow, and in return, receives sugars from the photobiont which are the products of photosynthesis. When the mycobiont and photobiont join, they both change physically and chemically to become a lichen. The fungus is said to be “lichenized”.

Crustose lichen. Image taken 01/01/2024

Lichens are known in five forms:

  • Crustose – ‘crusty’, firmly attached to substrate
  • Foliose – ‘leafy’, with rhizines, loosely attached
  • Fruticose – ‘bushy’, branching
  • Leprose – ‘powdery’, dusty coating, likes shady places
  • Squamosa – ‘scaly’, leafy scales

Fruticose lichen. Image taken 01/01/2024

Lichen and bryophyte. Image taken 01/01/2024

Harptree Woods, Mendip

Boxing Day, a local walk.

In the past, forestry operations in Harptree Woods, Mendip channelled surface water into naturally occurring sinkholes. The drainage for these sinks is localised and there are several springs along the flank of Garrow Bottom, including Garrowpipe Spring, where the water re-emerges to flow into Molly Brook.

I had a tentative poke into this sink several years ago but gave up due to the instability of the small chamber gained. It has since slumped and filled in with debris.

Wookey 20 to 24, the connection!

The expansion of the Wookey Hole showcave by a driven tunnel into Wookey 20 was completed in 2015. The tunnel allowed easy access to the cave passages beyond by ‘dry’ cavers, more specifically to ‘diggers’ eager to check out the potential leads. In late 2015, the regular diggers at Hallowe’en Rift were invited to take a look at a lead on the east side of the far reaches of Wookey 20. This route had been explored by divers, Tom Chapman and Keith Savory, in the 1990s to a low and too tight arch. There followed a period of expansion and induced rapid speleogenesis culminating in about 70m of gnarly passage gained and leading to another sump, named ‘23¾’, linking to the Sting Corner area in Wookey 24. Diving continues in this area.

In early August 2020, another project was set in motion by the regular team of Wookey Hole diggers in a small side passage off the route that leads down to sump 23¾. Following a collaboration between divers and diggers to establish a voice connection and pinpoint the best location, an intense digging effort of almost non-stop activity, finally, on the evening of October 29th 2020, a ‘non-diving dry’ route from Wookey 20 to Wookey 24 was completed by Vince Simmonds, Nick Hawkes, Graham Johnson, Mike Moxon, and Duncan Price. The route, following the small side passage off the route to sump 23¾, connects to the recently discovered extension, Beginner’s Luck, above the streamway found by divers, Connor Roe, Max Fisher, and Duncan Price leads down a steep descent into the Wookey 24 stream passage. The route is physically demanding, especially on the return, and has some difficult, awkward climbs.

A few days later, the English government plunged everyone into a second lockdown and our activities were, somewhat curtailed. This also meant that several of the regular diggers, absent on the breakthrough, had not yet passed the connection to Wookey 24. We are still in lockdown!

Subsequently, a disappointing and blatant “poacher’s” trip to the connection has occurred. Video clips of the trip were posted, then removed, there was some negative feedback posted on various platforms along with a lot of bullshit and bollocks being uttered. It is categorically stated here that none of the participants involved on this “poacher’s” trip were, or have ever, been involved with any of the digging activities to make the connection to Wookey 24 or any of the other recent discoveries in Wookey 20 (Land of Hope and Glory) and any inferences of such is just not true!

There was a rapid response to this post, a dialogue ensued and an apology received. It still rankles, but the clock can’t be turned back and we need to move on rather than enter an endless cycle of recriminations and finger-wagging. A line was drawn under it.

Pool Farm cist-slab, Hautville’s Quoit, and Fyfield Down Sarsens.

Some brief notes on the similarities of the rock-types of Pool Farm cist-slab, Hautville’s Quoit, Somerset, and Sarsen Stones at Fyfield Down, Wiltshire.

On a recent visit to Bristol Museum to view an exhibition – The Cave Art of Lascaux: A Virtual Reality Experience, I took some time to examine the Pool Farm cist-slab on display in the “Curiosities” section.

In 1930 a round barrow was excavated at Pool Farm, West Harptree, Somerset (NGR ST 5375, 5417). At the centre of the barrow a stone cist was discovered. The cist was constructed from several slabs comprising Dolomitic Conglomerate, Carboniferous Limestone, Liassic Chert, and sandstone. In 1931, the barrow was removed, and the material used for road-widening, the cist was left in-situ (Grinsell, 1958). The ‘carvings’ on the Pool Farm cist slab were recognised in May 1956 when the slab was removed to the City of Bristol Museum where it still remains. A replica of the slab is on display at Wells and Mendip Museum.

Pool Farm cist-slab on display at Bristol Museum

In Grinsell (1958) the cist slab rock type is described as “…a fine-grained pinkish sandstone containing numerous lamellibranchs”. Lamellibranchia (and Pelecypoda) are alternative names for Class Bivalvia, Phylum Mollusca. The bivalves are distinguished from other molluscs by their laterally compressed body enclosed between two bilaterally symmetrical, calcareous valves which are joined on the dorsal side by an elastic horny ligament. The bivalves are entirely aquatic, found in both marine and freshwater environments, the majority in shallow water. The fossil record of the Mollusca dates from the earliest Cambrian to Recent. Modern examples of bivalves include clams, cockles, mussels, and oysters (Black, 1988). A later description by Roger Clark, [then] Curator of Geology, at Bristol City Museum presented in Coles, et al (2000) reports “that the stone is almost certainly from the Harptree Beds, which consist of siliceous limestones and calcareous shelly limestones: these outcrop on the northern slope of the Mendip Plateau between East Harptree and Oakhill. The slab has abundant traces of decalcified bivalve molluscs, mostly corbulids and/or nuculids. The stone is local, perhaps coming from within a kilometre or so of the barrow”. Nucula is a Mesozoic bivalve living an a richly organic substrate from offshore to abyssal depths. Date ranging from Cretaceous to Recent (Black, 1988).

Personally, I do not agree with Clark’s assignment of the rock-type as originating from the local Harptree Beds. The rock-type of the cist-slab bears some remarkable similarities to that of Hautville’s Quoit at Stanton Drew, where a detailed archaeological investigation of the scheduled ancient monument (Monument No.BA44) was undertaken by the author and members of the Bath and Camerton Archaeological Society (BACAS) and a report was later published in 2012 in collaboration with Bath & North East Somerset Council.

A closer look at Pool Farm cist-slab

Hautville’s Quoit is located at Quoit Farm, near Stanton Drew (NGR ST 60173, 63811). According to the BGS 1:50 000 Map (Sheet 264) the underlying geology comprises Mercia Mudstone strata of Triassic age, this in turn overlies, unconformably, strata of Supra – Pennant Measures which form part of the Upper Coal Measures of Carboniferous age, below at an unspecified depth. 

Hautville’s Quoit showing surface features

To the east and south of the site is alluvium of Pleistocene and Recent age; also, to the east of the site and below at unspecified depth is the Pensford No.2 Coal Seam. The soils found at Quoit Farm are likely to be derived from the erosion and subsequent transport of material from the Lias strata of Jurassic age that forms the high ground to the north of the site.  In particular, from a layer consisting of mainly clay and shale, there is a substantial area of landslip on the slopes of Maes Knoll (East Dundry) and around the village of Norton Malreward.  The strata that comprise the landslip are described as mainly clay with White and Blue Lias, mainly limestone, also of Jurassic age.  The clay content of these soils is likely to retain a higher moisture content than the sandy soils of the stone circle site on the south side of the River Chew. 

Hautville’s Quoit consists of a pale brown to grey sandstone. The sandstone can be described as comprising subrounded to rounded (high sphericity), fine to medium (250 – 375 microns), well to medium sorted, shiny, polished, mostly translucent grains of quartz, that appear matrix supported in a siliceous cement.  There are noted numerous small clam-like (bivalve) fossil shells measuring up to 10mm x 6mm in an area of exposed bedding surfaces, these fossils are possibly a marker bed and might be useful in determining the origin of the rock type; these fossils have not yet been identified.  A white scaly appearance on some parts of the stone was likely due to lichen growth or as a result of weathering. The pock-marked surface might be the consequence of a number of factors, including the effect of roots or solution.  There are a number of lines of cleavage and other surface features visible on the stone. With regard to the Pool Farm cist-slab, Coles et al (2000) observe that “The whole surface of the slab appears to have been ground down to make some sort of uniform canvas for carving…”

Other surface features visible on Hautville’s Quoit

Discussion and follow-up fieldwork:

On a purely personal note, the rock type that comprises Hautville’s Quoit is not one that is recognised either locally, or in the broader surrounding area. There are a number of features of the stone that require further consideration.  Some subsequent fieldwork in the Mendip area has been carried out in the Ebbor Gorge area to look at exposures of the Quartzitic Sandstone Group (QSG) associated with the Ebbor Thrust.  However, it is thought unlikely that this particular exposure provided the source for Hautville’s Quoit.

Lloyd-Morgan (1887) described the rock type that comprises the quoit as fine-grained sandstone. Lloyd-Morgan hesitates to offer any opinion as to the source of sandstones found at Stanton Drew, either that of the quoit or the stones found in the stone circle close by and states, “of the source, geological and local I am doubtful”, he does, however go on to ask the question “Is it possible that one or more of the sandstone monoliths may be sarsen – but whence?”  

Roger Mercer, Inspector of Ancient Monuments for the Ministry of Public Buildings and Works, carried out an excavation at the site in 1969 and also attributes the stone as of ‘Wiltshire sarsen stone’ origin.

Hardy (1999, p. 176, 181) in his book ‘The Geology of Somerset’ describes a ‘tough silica-cemented sandstone found as loose masses in the surface of softer rocks’.  A number of these ‘sarsen’ stones were uncovered during the construction of the M5 motorway in the Blackdown Hills area close to Taunton but many of these appear to have been ‘lost’. 

The references of Lloyd-Morgan and Mercer prompted a field trip to Fyfield Down in Wiltshire, an area that is renowned for the sarsen stones, also called ‘grey wethers’, that are found there, and many have been used in monument sites such as Avebury and Stonehenge. There are a number of similar features in the stones at Fyfield Down and Hautville’s Quoit.

Surface features on ‘sarsen’ stones observed at Fyfield Down.

Grey ‘wethers’ can generally be described as sandstone that comprises of grey, fine to medium (250 – 375 microns), sub-rounded to rounded (high sphericity), well sorted, shiny, polished, mostly translucent grains of quartz, the clasts are contained in a matrix comprising siliceous cement.  Occasional stones were also noted to have variable colour from a pale grey-brown to more orange, possibly a result of iron content.  Some of the stones contained rare flint nodules and very occasional fine to medium, sub-rounded to rounded gravel of quartz.  The shape of the ‘grey wethers’ was also variable from rounded and spherical to more sub-angular blocks, with sizes ranging from <1m3 to several m3.  It should be noted that no occurrences of fossils were noted in any of the stones observed at Fyfield Down.  

Some further rock-types that might be considered:

The chert from the Upper Greensand that occurs in the Blackdown Hills near Taunton was formed as silica solution in the ground water filled the voids within the sandstone to convert it to quartzite or chert; this rock-type is of Cretaceous age.  Fossils found in these sandy sediments are preserved in a similar process as silica replaced the calcium carbonate content of the shells (Hardy, 1999, pp. 176, 181).  A field trip to this area to examine any outcrops or older buildings might provide further evidence.

Ganister is hard, fine-grained quartzose sandstone cemented with secondary silica and typically has a characteristic splintery fracture.  Cornish miners originally coined this term for hard, chemically, and physically inert silica-cemented quartzose sandstones, commonly, but not always found as seatearths within English Carboniferous coal measures.  Where a ganister underlies coal as a seatearth, it typically is penetrated by numerous root traces. These root traces typically consist of carbonaceous material. Ganisters that contain an abundance of fossil roots, which appear as fine carbonaceous, pencil-like streaks or markings, are called “pencil ganisters”. In other cases, the root traces consist of fine, branching nodules, called “rhizoliths”, which formed around the roots before they decayed (Wikipedia, online, accessed 30th April 2012).  It is feasible that this rock-type was found within the Coal Measures in the Pensford area but no reference to it has, so far, been found in publications accessed.

X-ray fluorescence (XRF) is a non-destructive analytical technique used to determine the elemental composition of materials. Hand-held analyser units are widely available (although expensive) and might provide useful information regarding the relationships, or not, between these rock-types.


Black, R.M. 1988. The Elements of Palaeontology, 2nd Edition. Cambridge University Press

British Geological Survey, Natural Environment Research Council, 1: 50 000 Series.  Sheet 264, Bristol, Solid and Drift Edition.  Ordnance Survey, Southampton.

Coles, J., Gestsdóttir, H., and Minnitt, S. 2000. A Bronze Age Decorated Cist from Pool Farm, West Harptree: New Analyses. Proceedings of the Somerset Archaeological and Natural History Society. Volume 144 (2000): pp 25-30

Grinsell, L.V. 1958. A Decorated Cist-slab from Mendip. Proceedings of the Prehistoric Society, Volume 23, January 1958, pp 231-232

Hardy, P. 1999. The Geology of Somerset.  Ex Libris Press, Bradford on Avon.

Lloyd-Morgan, C. 1887. The Stones of Stanton Drew: their source and origin, Part II. Proceedings of the Somerset Archaeological and Natural History Society. Volume 33 (1887): pp. 37 – 50.

Mercer, R. 1969. Hautville’s Quoit Excavation Notes includes Clark, A.J. Geophysical Survey Report (Unpublished)

Richards, J., Oswin, J., and Simmonds, V. 2012. Hautville’s Quoit and other investigations at Stanton Drew. Bath and Camerton Archaeological Society in collaboration with Bath & North East Somerset Council.

Holy Man’s Cave, Folly Wood, south of Devizes, Wiltshire

NGR SU 018 570

Holy Man’s Cave

At Folly Wood, Easterton Sands, south of Devizes, a small ‘cave’ is located on the southwest side of a small gorge/ravine with sunken lane at its base. The ‘cave is found mid-section of an exposure of Upper Greensand, described as sand and sandstone, fine-grained silt, glauconitic, shelly, formed during the Cretaceous Period, 113 and 93.9 million years ago and very close to the geological boundary with Gault Formation – Mudstone formed between 113 and 100.5 million years ago during the Cretaceous period. (BGS, online). The entrance, ca 1-metre-high x 0.5-metre-wide, leads to a small chamber with abundant pick-marks evident on both sides and roof, the passage soon lowers and closes down, overall length <6 metres. There were etchings/inscriptions in the chamber and to the left side of the entrance, these were of modern date. The soft nature of the substrate makes it likely that potential inscriptions of older date have been eroded away.

Inscriptions can be seen on right side of entrance (and in the cave interior)

The anthropogenically altered ‘cave’ might have an alternative identity as described below:   

…Quabb’s Hole. This was a hole dug out of the sand, on the hill above Maggot Castle, separated from the Folly by a deep ravine, where the land slopes from Easterton to Crook’s farm. Quabb was a loner, a poacher and petty thief, whose exploits have been much embroidered. He stole sheep and hens and poached when and where he could, living alone in his cave where he died. When discovered, the cave was full of sheepskins and feathers. It was then filled in and forgotten. The story is never heard now but the events must have taken place about the beginning of the 19th century.”(Market Lavington Museum, online)

It is interesting to note that “quabb” is possibly derived from the Old English word cwabba “marsh”. A reflection on the ‘soft ground’ in the surrounding area perhaps.

Sources consulted:

British Geological Survey (BGS), https://geologyviewer.bgs.ac.uk Accessed 18/09/2023

https://marketlavingtonmuseum.wordpress.com/2011/10/29/the-folly/ Accessed 14/09/2023

The ‘cave’ entrance is left of the tree roots on right side of image

South West Coast Path National Trail

May 28th to July 2nd 2023: Spent 36 days walking the 630 miles South West Coast Path National Trail from Minehead, Somerset to South Haven Point, Dorset. The coast path includes the Devon (north and south) and Cornwall coastlines. The walk was solo and self-supported using a variety of accommodation options, basically, whatever suited on the day!