Description
south-west, Bacon Hole has a large wide entrance which is partially blocked with fallen rock and sections of the fossil raised beach. The cave is 36m long with an entrance 18m in width and 6m in height. As with several caves in the area, Col. E.R. Wood carried out excavations in 1850 discovering Pleistocene deposits and recent fauna. One antler bone bore "distinct marks of having been wrought by human hands" (R.C.A.H.M.W. 1976 No14). An Iron Age bowl was found in superficial mud. Casual finds over the next hundred years indicate occasional domestic occupation of the cave. These finds are listed on the SMR record card, a copy of which is bound into the back of the report. Excavations carried out by the British Museum (Natural History) in the 1970's and 80's revealed a complex stratigraphy in the cave earths (Stringer 1975, 1977). Bone finds included bison, elephant, rhinoceros, red deer and hyena. These discoveries were used to demonstrate that the complexity in the faunal change between the last interstadial or warm climatic phase and the last glaciation was more complex than previously thought (Stringer et al 1986).
2003 survey
A cave with a large wide SW facing entrance, 18m wide and 6m high. The main chamber is currently about 36m deep, Evans describes it as 60m long. A second chamber leads off to the NE, 3m wide and 7.5m long. The name apparently came from a "stratum of stone much resembling a rasher of bacon" (Oldisworth 1802). Davies (1928) however suggest Bacon may have been a local celebrity who took refuge there is press gang days, or that it may have been used to store fuel for the nearby Beacon, then apparently some 300yards away. Several white lines can be seen on the walls of the cave, presumably made during excavations or surveys of the cave. The ground appear quite disturbed from the numerous excavations undertaken.
The cave was first excavated in 1850s by Wood, in the 1900s by Morgan, in 1943 by Allen & Rutter, and finally between 1974-84 by Stringer and Currant for the Natural History Museum. The excavations revealed a complex but well stratified sequence of cave earths and fauna formed by marine and terrestrial process, belonging to the Devensian and Ipswichian. They have been used to reconstruct a series of Pleistocene events, demonstrating the transition between the last interstadial (warm climatic phase) and the last glaciation was more complex than previously thought. It has been possible to monitor the marine activity through the presence of beach material, marine modified sand grains, marine and littoral fauna (molluscs and fish). Local environments can be reconstructed by studying faunal remains, molluscs and fossil pollen. Methods such as uranium series techniques and amino acid geochronology have been used to date some deposits. These excavations enable a list of deposits to be made in ascending order.
1. Stalagmitic layer, deposits accumulated on the base of the cave, possibly of littoral origin, dated to 175kyr BP +/-19kyr.
2. Coarse grey sands, deposited during a period of cool dry climate with relatively open vegetation after much of the previous layer was removed by high sea levels (pre OIS 5e)
3. Coarse orange sands, showing an increase in locally derive angular limestone fragments ad mixed deposits indicating a damper and possibly warmer climate. Fauna from 2 and 3 included horse and northern vole suggesting boreal open country conditions, backed up by the finding of land snails. The remains also included fox and razorbill. The restricted fauna suggest bare cliffs and scree slops indicative of glacial or early interglacial condition.
4. Sandy breccio conglomerate, interpreted as a storm beach similar to the Patella beach of Minchin Hole, related to sea levels similar to today, dated to c122kyr BP. Faunal remains included wood mouse, field vole and red deer.
5. Sandy cave earths, consisting of large limestone fragments with shelly lenses, formed under moderately warm humid conditions.
6. Shelly sand, some limestone fragments but dominated by banks of wind blown marine shell debris derived from an extensive exposed beach during a recessive phase. Generally these 1st three deposits show a rise in sea level, temperature and humidity. Mammal remains such as red deer, wood mouse, field and bank vole suggest a temperate mixed oak forest. Sand grains suggest part marine origin but possibly warm conditions. Foraminifera (minute invertebrate), associated with seaweed, also indicate a shallow water environment. The sandy cave earth and shelly sand also produced the remains of pygmy and common shrew, water vole, hare, straight tusked elephant, lion, red fox, and fallow deer. Bird faunas included Cory's Shearwater, now nesting birds of southern Europe. Layer 6 was dated to roughly 116-129kyr BP.
7. Grey clays, silts and sands, linked to falling sea levels and temperature. Mammoth is now first recorded, giant ox, bison, northern vole and bean goose are also present, pointing to a return to boreal conditions. Bird fauna is now dominated by winter visitors, sea birds disappear suggesting a lowering of sea level, confirmed by a lack of marine invertebrates. The grey clays show periodic wind-blown deposits and waterloggin, possibly indicating climatic instability. Other faunal remains include field, water and bank vole, straight tusked elephant, narrow-nosed rhinoceros, spotted hyena, wolf, red deer and roe deer. The hyena was making heavy use of the cave during this period, bringing in many of the large mammal bones. Also apparently discovered from this deposit were bones with polished ends, microscopic analysis showed this was probably caused by absorbed grease, consistent with their use for a purpose such as dressing animal skins. It is argued that the non-random scratches on the ends of the bones are unlikely to have been caused naturally, possibly indicating direction of rubbing during se, suggested as representing the earliest evidence of humans in Wales, although this has recently been refuted by Currant (2001).
8. Upper sands, these deposits indicates a drier phase, built up of wind blown sediments and Foraminifera typical of modern British coastal waters, but no indication of temperature.
9. Upper cave earth, consisting of limestone fragments in sandy silt. This deposit was apparently the source of a major collection of large vertebrate remains during Woods' excavation, including wolf, hyena, red deer, straight tusked elephant, bison, narrow nosed rhino, northern and water vole, and land snail, seemingly interglacial in character. They suggest a local environment of woodland and scrub, the absence of marine and littoral molluscs and the general make up of the deposit implies distance to the sea. The prevailing climate was cooler and dryer then 7. But still temperate. The overlying deposit has been dated to around 81kyr BP (+/-18k), but later redated to approx. 87kyr BP with a tight error margin, marking the date between interglacial and glacial fauna.
10. Cemented breccias, massive collapse[ enlarged entrance, deposits collected from the cliff above, containing cold climate fauna, including reindeer and wolverine. Samples of upper stalagmite floor suggest an age of around 13 kyr BP.
Together with Minchin hole the deposits enable sea level and palaeotemperature data to be correlated with the deep sea oxygen isotope record. The information gained concerning the nature and complexity[ of the Ipswichian-Devensian transition is important as it leads directly to the last major ice age. It also provides more evidence for the British late Pleistocene against which the factors governing human presence and absence can be assessed.
The archaeological material from the cave shows a broad date range, although pre-Iron Age finds all appear debatable. Aside from the polished bones mentioned earlier polished ivory objects found by Griffiths have been attributed to the Palaeolithic, however this evidence of early human activity was later refuted by Currant. Several red bands on the cave wall were interpreted by Prof. Sollas and Abbe Breuil in 1912 as Palaeolithic cave art but have since been proven top be natural. Iron Age potsherds have been recovered, some bowls found in the late C19th have been dated to C300 BC. Other finds include a Romano-British bone pin, a bronze brooch of Irish influence from the C7th, a number of Saxon-type beads, medieval cooking pot sherd and a bone flute (possibly late Norman). These finds would seem to indicate periodic short term domestic occupation of the cave.