Wednesday, 29 July 2020
Derbyshire Bone Caves 6: Thor's Cave
Thor’s Cave is the most striking cave of the manifold valley. It lords it above the Manifold Trail about a mile SSE of Wetton Mill. From whatever angle you view it, it’s vast maw is an awe inspiring and slightly unsettling sight. The vast hole in the beetling crag seems to whisper “I’m here, I’ve always been here.. Enter if you dare!” And it’s true: Thor’s Cave is an ancient product of the Earth’s contorted history, a long tale with many facets; hinted at by its bulk and stygian darkness. So let us use science to unravel its mysteries and origin, before we approach its myth swathed portal.
Thor’s Cave by the author, June 2020 (see note 2 below).
The limestones of the Manifold Valley area were formed in warm tropical seas 325-355 million years ago, during the Carboniferous period. These ancient seas teemed with life: brachiopods, corals, crinoids and ammonites all flourished.
Ammonite from Thor’s Cave. SWCHS Geology (2018).
The rocks were laid down by the deposition of layers of sediment, mostly shell debris and mud, that were later compacted and cemented by calcite into hard beds of limestone and thin shale. This layered sequence also contains lens-shaped masses of reef limestone that lack obvious layering. These reefs were generally formed in shallow water.
At this time, Britain lay close to the equator, near the southern margin of the ancient continent of Laurussia. Later, these deposits were buried beneath younger Carboniferous rocks of the Millstone Grit and Coal Measures. At the end of the Carboniferous, about 300 million years ago, Laurussia and Gondwana collided in the south. The many folds, faults and fractures (joints) in the area, date from this time. Later, hot fluids circulating through the fractures deposited valuable minerals.
During the Permian, Triassic and Jurassic periods the continents continued to drift. New continents formed and split. By 200 million years ago during the Triassic, Britain was part of Laurasia, which had almost entirely split from Gondwana and now lay north of the equator.
During the Cretaceous North America, finally split away from Laurasia and drifted west. At 65 million years ago the cometary impact that caused the extinction of the dinosaurs occurred. Before we get to the start of the geological story as it pertains to Thor’s Cave a couple of other minor events happened: India collides with Laurasia (50Mya) and Australia completely separates from Antarctica (45Mya).
At 2 million years ago, the plateau overlying Thor’s Cave was largely intact. Surface water percolated down through the Millstone Grit and Coal Measures rocks and into Carboniferous Limestone. The faults and fractures formed millennia ago began to be eroded. The sequence of events is quite complex and it is worthwhile to take a couple of minutes to consider the process.
Underground passages in limestone areas are made almost entirely by solution rather than erosion. Water picks out lines of weakness and solution is concentrated at these points.
A bedding plane at the top of a particularly hard bed in the limestone (or perhaps an impermeable bed of shale within the limestone) could be more resistant to solution and erosion, so that rain water percolating down from the surface preferentially dissolves the overlying limestone.
Water is also able to seep along the bedding plane, so that the sites where solution is happening are joined up by tiny channels.
Solution continues and the tiny channels widen from a few millimetres to a few centimetres. One channel may start to take more water than the others and enlarges to become a small phreatic cave. Water flows more easily through the cave, solution is more rapid and the cave increases in size.
The increase in water flow also increases solution (and erosion) of the more permeable limestone below, and the phreatic tube grows in diameter.
Eventually, a cave forms. If it is entirely below the water table and phreatic solution continues on the floor, roof and walls and the cave takes on a bigger and bigger, more circular or tube-like shape.
Rivers running across the surface of the plateau above the limestone in which Thor’s Cave formed, eventually cut down below the level of the cave. Coincidentally, the nascent Manifold happened to cut across the huge phreatic tube of the cave’s north entrance. Now a huge cave entrance was revealed approximately 10m high by 7m wide! See note 1 below for sources.
According to Rowe et al. (1988), analysing data on spelothems from Elder Bush Cave, a cave approximately 100m away and at a very similar altitude dates for the ‘fossilization’ of Thor’s Cave can be fairly well determined: ““Analyses of uranium and thorium isotopes in calcite samples from thick flowstones within a high level relict cave remnant (Elder Bush Cave) indicated that the formations were beyond the range of the uranium-thorium dating technique (350 ka). 234/U//238/U isotope activity ratios approached unity, suggesting that the flowstones may have formed a considerable time before 350 ka. Palaeomagnetic samples taken from cores drilled through the flowstones showed the presence of both normally and reversely magnetized calcite. In some cases reversely magnetized layers overlie normally magnetized layers. This evidence, taken in conjunction with the uranium isotope data, is interpreted as indicating an Olduvai age (1.66-1.87 Ma) for some of the flowstone horizons. It is suggested that the cave became vadose by or soon after 2.0 Ma. The position of the cave near the valley rim enables an estimate to be made of the maximum rate at which the present valley has been excavated. This is calculated to be 5.5 cm/ka. Remnants of old valley floors preserved within the existing valley suggest that downcutting has been a continuous process. Flowstone from a cave on one of the lower valley floor remnants (Darfur Ridge Cave) has been dated to 284 +34/-27ka allowing a maximum downcutting rate since that time of 11.2 cm/ka. The proximity of Elder Bush Cave to the valley crest suggests that its abandonment marked the onset of the incision of the present system of dales that characterize the English Peak District, presumably initiated by epeirogenic uplift or tilting.”
Thor’s Cave had become a ‘fossil cave’ – a dry and stable cave above the water table and one extremely inviting to humans from perhaps 200,000 years ago right up to Saxon times.
Thus the spectacular gorge of the Manifold valley was formed by the erosive and solutional, effects of running water on the Carboniferous Limestone plateau during the last 2 million years. When it was first occupied by humans, is a matter of conjecture, but an early excavation uncovered a considerable amount of evidence.
Information on the first excavation of Thor’s Cave, by Samual Carrington in 1864-5, is very sparse, due to no full account being available on the net.
But who was Samuel Carrington? Luckily I stumbled upon a short biography by Zoeteweij (1986), the following is adapted from that work.
Samuel Carrington of Wetton, Staffordshire, son of Samuel and Ann Carrington, was baptised in Wetton Parish Church on 25 November, 1798 and buried in the churchyard there on 14 October, 1870.
Samuel Carrington from Anon (1874) via Zoeteweij (1986).
Samuel junior was sent to the village school at an early age, and then followed his father down the mines, at Ecton. In his twenty-first year Samuel and his father emigrated to America but he was dissatisfied with that country and gladly returned home with the intention of never quitting again his native parish.
By 1823 he was married and had gained jobs as the village schoolmaster and parish clerk. Carrington, was a careful collector of Carboniferous fossils over many years. In particular, he collected many fine and unusual examples of brachiopods, including several new species described by Thomas Davidson (mostly in 1863); some of these remain unknown from other localities and with insecure classifications. The value of Carrington's material lies in the detailed notes on localities and associated faunas which accompany his fossils, and which Davidson commonly quoted in his publications. Several of these notes remain with Carrington specimens in the collection of material figured by Davidson in his classic Palaeontographical Society Monographs, now housed in the British Museum
A good friend, [Anon (1874)], who met Samuel Carrington in about 1835 describes him thus: “His studies then were mostly botanical, and he was accustomed to make drawings of almost every wild plant he met with. They are extremely accurate, and have the natural air, so as to be immediately recognised. He was also observant of insects. His geological and antiquarian researches were only just begun, arid his few specimens, some of which were then of the wonderful description, occupied a portion of his pantry. We could hardly foresee that he was to become one of the most assiduous collectors in England, doubtless so of mountain limestone fossils, and the discoverer of many new forms, some of which bear his name. Under the patronage of the late Mr. Bateman, of Youlgreave, he commenced that course of barrow opening which has rendered both of them well known to archaeologists. Our friend took a good share of the work; he also made special researches on the sites of ancient British dwellings at the Borough in his own im mediate neighbourhood. Under the auspices of the Midland Scientific Institute he extended researches, which had been previously made, in the floor of Thor's Cavern; many remains of a Romano-British character were found, though none of primeval man..
He took an interest in the topography of his own district, unsurpassed as it is in objects fitted to create it; each rock and tor and cairned hill summit, each dale, fissure, or cavern, was well known to him, and he took much interest in the derivation of their name.”
As mentioned above, there is very little information on the first excavation of Thor’s Cave, by Samual Carrington in 1864-5, due to no full account being available on the net.
So, let me remedy that for you. Below is a direct transcript of Carrington’s (1865) account published in The Reliquary of which I was very happy to discover a copy for sale in Ireland.
Thor’s Cave from Carrington (1866). Note that in the view of the west entrance at right, a small elliptical mark at the top of the gully may be seen Thor’s Fissure Cave, the subject of a future post.
Carrington gives quite a thorough account of the excavations, contrary to what some commentators say:
“The cave, although partly choked with mud, has long been esteemed as the greatest natural object of curiosity in these parts. The interior, even before operations were commenced to clear it, was both chaste and grand. From the centre a massive pillar arose from the floor perpendicularly to the roof, where it spread out like a palm-tree, giving a cathedral appearance, and a greater security to the roof. A second pillar, called the altar, rose immediately beyond this and reached about half the height of the other, dividing by their junction the cave into two parallel passages, the capacious one tending in a straight line towards the east; the other turning at a right angle with the altar towards the south. The mud or clay formed a smooth floor, which from the trampling of visitors during ages, was almost as impenetrable to the shovel as a macadamised road; at the main entrance it formed but a thin layer, which rapidly increased in depth, forming a steep slope, that almost reached the roof at the end of the east branch, yet leaving sufficient room for a man to creep along the tops of the fissures into which this branch is divided.
About one half of the south branch was completely blocked up. In addition to the great northern, there is a large open cleft in the west side (shown on Plate XVII), in a direct line with the east division, so that betwixt them the interior to a short distance beyond the altar was well lighted. Beyond them, owing to the rapid rising of the mud, it gradually merged into total darkness.
Several excavations have been made in the cave by different persons in the expectation of discovering the remains of extinct animals without success, still it appeared probable that something of an interesting character might be brought to light, by clearing out the whole.
Stimulated by this belief, Mr Edwin Brown, of Burton-on-Trent, pointed out to members of the Midland Scientific Association, the possibility of the relics of primitive life being buried therein, when the sum of five pounds was voted towards the operations, and it was agreed that the objects which might be discovered should be deposited in the Derby Town and County Museum. The consent of His Grace the Duke of Devonshire was obtained, when I, at their request, undertook to superintend the operations, which accordingly were commenced the second day of September 1864, and continued at intervals until the third day of October 1865.
Frequently six labourers were employed, so that the first grant of money was soon expended; but liberal subscriptions from individuals enabled us to carry on the work, when but little hopes remained of anything further being added to what already was found. The form of the Cave will be best understood by the plan given on Plate XVIII.”
Thor’s Cave floor plan from Carrington (1866).
Thor’s Cave floor plan from Brown (1865). Original caption reads: Plate 2, Fig. 1 – Plan of Thor’s Cave shewing the width of the passages at about five feet above the line at which the excavations ceased.
The letters refer to the sections on plates 2 and 3.
N. The grand entrance facing nearly due north.
Q. The Narrow opening in which occur the tidal marks.
R. R’. R’’. R’’’. narrow fissures which have not yet been explored. These are filled very nearly to the level of the top with clay.
S. Unexplored passage filled with clay.
T. Lofty detached stone, called the ”Altar Stone.”
T’. T’’. Columns of stone, reaching to the roof, and dividing the cave into two aisles.
U. The place where the female skeleton was discovered.
W. The place where the ancient fragment of deer’s horn was discovered.
The shading indicates the portion of the floor in which antiquities were found.
Figs. O.N. and P.N. represent longitudinal sections, in which the dotted portions indicate sand; the diagonal shading, diluvial clay; and the cross shading that portion of the clay which had been disturbed by the dwellers in the cave.
Transverse sections of Thor’s Cave from Brown (1865). Original caption reads:
Plate 3 – Six transverse sections of the cave, in which the sand, clay and mud are indicated as on plate 2, and the breccia and charcoal floors by respectively, strong, irregular and diagonal lines.
The lines exterior to the sections show the dip of the rock.
A.B. Breccia; sand and mud
C.D. Pebbles; sand and small pebbles in layers; mud with layers of charcoal.
E.F. Sand; clay and mud
G.H. Stratified sand, which is agglutinated by calcareous infiltration on the side towards H; clay with fragments of fallen rock.
I.K. Sand; clay under and overlying a broken floor of breccia. At a was found the ancient fragment of deer’s horn.L.M. sand stratified and tilted at a high angle; clay with masses of breccia, partly adhering to the side L, and partially dispersed through the clay in masses.
“We began by clearing the floor a little within the north entrance, where it rose too abruptly for a wheelbarrow road, consequently we made a causeway on the west side so as to get a level with the interior, and also more effectually to cast out the debris down the precipice in front. Another raised way was formed through the west aperture, so that two sets of men could be employed without hindrance to each other. We had not been long at work before it was apparent that it had been occupied by man, by finding the mud intermixed with ashes, animal bones, and fragments of pottery. Shortly an instrument of green stone, somewhat resembling a Celt, turned up, then a square whetstone, after that the fragment of a quern, a sandstone disc perforated in the centre, and an instrument formed by the brow antler of the stag, cut and perforated much like a whistle. On the east side of the passage, just before it reached the turning point to the east branch, we found a circular pavement close to the rock, formed of very thin stones, with much charcoal and ashes upon and around them. Many instruments, formed of various materials, were discovered in the wide part, just before we reached the first pillar. On approaching it we found a bed of ashes at the depth of two feet, which the labourers denominated the “Midden.” Many animal bones and potsherds were mixed up in it. On arriving at the pillar, after digging through one foot of mud or clay, we came upon a bed charcoal which extended from the pillar to the opposite side, it was more than one foot thick and free from any mixture whatever; about a foot below this was another bed of charcoal, about the same thickness as the first; this was intermixed with bones and some fragments of pottery. Again after digging through another intervening foot of clay, we came upon a third bed of charcoal, in which bones and pot-sherds were found in greater abundance than in the other; also some instruments of iron, comprising a large fork, a broad cutting instrument, and some other implements of the same material, but of indeterminate use. These alternate beds continued pretty uniform to the extent of about 9 feet along the passage. Arriving at a large loose block of limestone, we found that some previous explorer had dug down to the rock through clay and sand a depth of seven feet, but had overlooked one of those singular whistle-like instruments, which we found near the bottom of the original excavation. The next discovery was made near to the altar, which was that of a human skeleton, minus the head and lower arm bones. It lay on its left side, with the shoulders to the north-east, in the primitive contracted position, a very unusual one in the period which the interment will appear to have taken place [Boyd Dawkins (1874) suggests that this was characteristic of the Neolithic interment in Europe]. Open burrows, such as might be scratched out by foxes, were round and beneath the skeleton, which may account for the dismemberment; an upper jaw with one tooth remaining attached to it, and two ulnae, were found in the sand lower down, and seven feet from the surface. The Femur measured sixteen inches, and is apparently female. A “whistle” similar to the others was found in close proximity to the interment.
Collection of “whistles” excavated by Carrington, the one 3rd from the left was found with the female internment.
Modern analysis of the “whistles” from Thor’s Cave identifies them as cheek pieces for use in a primitive, Iron Age bridle and halter. Indeed, some examples may well be for this use, however not all the antler examples shown above fit this pattern. Of particular note, in this regard is number 35, found with the Neolithic, crouched burial of a woman as the use of horses as beasts of burden and for riding did not arrive in Britain until the Bronze Age. Photo from Wonders of the Peak (2020).
We had not proceeded far from the grave, when we found that another and deeper excavation had been made and again filled up, which was indicated by the mixture of animal bones, broken pottery, and stalactites from the surface, as in the other. They had penetrated to the rock through clay and sand, which here was fifteen feet in depth. An instrument of iron was found at the depth of ten feet, somewhat like a pickaxe. It is a little more than one foot long, and pointed at each end, and without any perforation for a helve. Our progress was now much impeded by some very large blocks of limestone that had fallen from the roof or sides, while the water was washing in the clay and sand. Some of these were buried, others were partly bare, but none were found as low as the rocky floor. But little was found of much importance (with one exception), in the south branch. A few small bones, and a tooth either of the hog or bear [Brown 1865 determined it to be bear] lay in vacancies that occurred betwixt the indurated masses of clay and sand and the rock. The bones of a fawn were found in one of the burrows, which abounded here in the sand as they did in the other branch. Soon after this division was entered an object was found, not of much importance in itself, but being found in a situation so unexpected is calculated to puzzle inquiries how or when it got there. The object alluded to is a brow antler of a stag’s horn, which was found imbedded in compact clay, that to all appearance had not been disturbed since the deposition thereof by water. A description of the superincumbent materials may serve to shew the puzzling position of the horn. Beneath one foot deep of mud or clay, a bed of conglomerated gritstone boulders extended nearly across the cave, being half-a-yard or more in thickness on the left hand, where it adhered to the rock. In the middle it was dislocated and towards the right hand side, where the horn was found, it lay in thin scattered fragments, none of which reached quite to the side. The horn was found at the depth of four feet from the surface of the clay, and nearly the same distance from the side of the cave. Now it could be proved that the horn could only be deposited there by the influx of water whether of a sea or a river, it would be corroborative of the extreme antiquity of man, but the greatest apparent probability will not satisfy the inquirer after truth. In this instance a doubt must ever rest upon every mind as to its real value as an index to that extreme antiquity, partly in consequence of the scattered fragmentary state of the conglomerate above, and the possibility that it might have got there by other means, and the cavity closed up by water trickling down the rock and carrying fine particles of clay, which in the case of two or three thousand years, and the trampling of man above, may account for the homogeneousness of the matrix in which it was found.
Many open burrows were found here in the underlying sand, as in the other part, being secured from the disintegrating effect of the atmosphere by the great accumulation of rubbish above, the scratches were as fresh as if but a day. One vault, from its superior size, we were inclined to attribute to the bear, the lower part was rubbed smooth by the creatures body, four indentations by the nails in the upper part of the vault measured across averaged 3 inches, their parallelism in fours seemed to be the effect of one stroke, the fifth toe being too short to leave any impression. There are many small rounded perforations in the sides of the cave, too straight for any animal larger than a badger or fox to enter, such of them that we found buried in the sand, had in all instances been directly reached, as if their whereabouts was known before the introduction of the sand, &c, by the water; perhaps they had been instinctively led by sound reverberated from them whilst scratching.
We have also noticed before that the fissures into which the east end is subdivided were not filled to the roof. It was thought advisable to investigate them, as in all probability they might have served for the retreat of pre-existing animals. Only a few small bones were found in the largest fissure, similar to others found scattered near the surface of the mud in other places. The largest fissure, from the width it began to attain before abandoned, appeared likely to be connected with one or more of the others. The work was now given up.”
Human worked horn found below all other artifacts in the cave and in situ with the clay, from Carrington (1866). Drawing by Carrington himself.
There is a second text describing the excavation of Thor’s Cave. This time by Edwin Brown of the Midland Scientific Association, who was instrumental in monies being found from his own association, to fund the dig by Carrington. Again, no version of the text is available online. Having obtained a copy via an antiquarian book dealer, I transcribe below a description of discovery of the most important find: the ancient perforated deer horn from the south branch of the cave:
“In the south recess, behind and below any signs of man’s occupation, the diggers came upon a kind of flooring of tabular masses of breccia, stretching almost across the cave, and on one side attached firmly to the wall, beneath this the mud consisted of almost of pure adhesive clay. In this perfectly undisturbed stratum, to which man apparently had never previously had access, the workmen came upon the end of a deer’s horn, cut across by means of some rude instrument, probably a flint saw, and perforated by two holes, most likely for suspension. This is a startling fact, - an indication of man’s existence prior to the latter portion of the glacial epoch! I have carefully examined into the facts of the case upon the spot, and, to my mind, on the supposition that the cave was really filled with clay by the glacial sea, the great antiquity of the relic cannot be doubted. Mr Carrington, I may remark, had no theory to support, indeed he was quite unprepared for such a piece of evidence, and his long experience in barrow research is an ample guarantee for his carefulness and discrimination.
May we venture to hypothesise, that men of the flint age lived contemporaneously in Derbyshire and Staffordshire, with the glacial sea? I do not know how otherwise to explain the occurrence of the manufactured horn in an undisturbed glacial deposit..”
The horn found in the clay of south branch of the cave, from Brown (1865) plate 14. Note that this is drawn by a different artist.
While both authors tend towards the horn being found in situ and undisturbed, Brown certainly argues the case for this most strongly. No C14 dating, as far as I am aware has been attempted on the horn.
How then are we to put a date for the deposition of the clay layer containing the horn? Fortunately some dating attempts have been made in regard to the formation of the Manifold Caves. Rowe et al. (1988) date the final evolution of the adjacent Elder Bush Cave into a vadose, fossil cave at or soon after 2.0 million years ago. The excavation of that cave by Bramwell (1964) showed a clear and undisturbed stratigraphy, with his layers 7, 8 and 9. These consisted of 9: red cave earth of stiff red clay; 8: Flaky stalagmite, a limited deposit found interstratified with layer 7 [but also shown in his Fig 2. as intrusive into layer 9] found in certain areas of the cave assumed to be ‘wet patches’; 7: Sandy cave earth. It was so named because it contained bones. The absence of clay binding the sand particles indicates dry conditions and indicates the sand probably has an aeolian origin.
Thus as the same sequence that is found in the Elder Bush Cave occurs in Thor’s Cave, we may hypothesise that the layer in which the horn was found is of the same age as some part of Bramwell’s layer 9. This has been accepted by modern authors, such as Lewis et al. (2011) as of Early Devensian age, or about 95-85Ka in MIS5b.
Admittedly, this is a stretch as only one other confirmed instance of man’s presence has been found in the UK of this age. The site in question is in Kent, where Wenban-Smith et al. (2010) found a lithic assemblage attributed to Neanderthals. However there was a similarly anomalously aged bone implement of similar age found in the Elder Bush Cave from the top of layer 9, namely a bone point made on a reindeer metacarpal worked to a point (see my post on Elder Bush Cave here).
Bramwell (1950) comments on the horn: “The most, interesting find in Thor’s Cave was a piece of roughly sawn deer antler pierced by two holes, as though for suspension. As this was dug from clay below the breccia, it seems to require a late Palaeolithic date. In view of undoubted late Palaeolithic material from Thor’s Fissure Cave and Elder Bush Cave, this would not be so unlikely.”
Therefore, Carrington’s excavation of Thor’s Cave, may actually have found what he was looking for: evidence of the extreme antiquity of man in White Peak, less than a mile from his house!
Anon. (1874) Memoir of Samuel Carrington, 2pp., + appendices. [Only copy seen (Figs.1-5) is in Stoke-on-Trent City Libraries, Horace Barks Reference Library*;
undated, but internal evidence suggests 1874.]
Bramwell, D. (1950) Cave Dwellers and Dens of Late Pleistocene Animals in the Manifold Valley, Staffordshire. Cave Research Group of Gt. Britain (CRG): Transactions Vol 1 (4) p43-52
Bramwell, D. (1964). The Excavations at Elder Bush Cave, Wetton, Staffs. North Staffordshire journal of field studies vol. 4, Page(s) 46-60
Brown, E. (1865). “The Exploration of Thor’s Cave" Transactions of the Midland Scientific Association for 1865. Pages 1-6, 19-30 and 70-71,
Dawkins, B. (1874). Cave Hunting, MacMillan and Company.
Carrington, S. (1866). “Account of the Excavations and Discoveries in Thor’s Cave, Wetton Dale”, The Reliquary, Vol. 6, April 1865-66
Lewis, S. G., Ashton N. and R Jacobi (2011). Testing Human Presence During the Last Interglacial (MIS5e): A Review of the British Evidence in Developments in Quaternary Science vol. 14 p. 131. N. Ashton, S. Lewis and C. Stringer eds.
Rowe, P, Austin, T, and Atkinson, T. (1988). Quaternary evolution of the British south Pennines from uranium series and palaeomagnetic data. Ann. Soc. Geol. Belg. Vol. 111:1 p97-106
SWCHS Geology (2018) at: https://twitter.com/swchsgeology/status/1002226424604917761?lang=en accessed 26.07.20
Wenban‐Smith, F.F., Bates, M.R. and Schwenninger, J.L., 2010. Early Devensian (MIS 5d–5b) occupation at Dartford, southeast England. Journal of Quaternary Science, 25(8), pp.1193-1199.
Wonders of the Peak (2020) at: https://www.wondersofthepeak.org.uk/facts/thors-cave/ accessed 26.07.20
Zoeteweij, F. (1986). Collections, Collectors and Museums of Note, No. 49 Samuel Carrington (1798-1870). Geological Curator, Vol.4, No.5, pp.281-286
1. The Geological information on the Manifold Valley and Thor’s Cave was drawn from numerous websites. For those interested, more information can be found at the following:
BGS (2020) at: https://www.bgs.ac.uk/discoveringGeology/geologyOfBritain/limestoneLandscapes/undergroundFeatures/Caves.html accessed 26.07.20
Earthguide (2008) at: http://earthguide.ucsd.edu/eoc/teachers/t_tectonics/p_pangaea2.html#:~:text=When%20Pangaea%20broke%20up%2C%20the,southern%20continent%20is%20called%20Gondwanaland. accessed 26.07.20
Encyclopaedia Britannica (2020) at: https://www.britannica.com/science/Carboniferous-Period accessed 26.07.20
Geolearning (2020) at: https://www.geo.fu-berlin.de/en/v/geolearning/gondwana/timeline/index.html accessed 26.07.20
Staffs Ecology (2020) at: http://srigs.staffs-ecology.org.uk/Geotrails/HampsManifold/hampsbackground.pdf accessed 26.07.20
Wikipedia (2019) at: https://simple.wikipedia.org/wiki/Laurussia accessed 26.07.20
2. Thor’s Cave is of course in Staffordshire, but for the purpose of this series I have appropriated a number of caves from adjacent counties to broaden the perspective of their occupation.