The Avon Gorge cuts through several different rock formations laid down hundreds of millions of years ago. The house is built on the Clifton Down Limestone Formation, laid down 153-277 million years ago, when the area that is now Leigh Woods was a tropical archipelago situated nearer the equator. The rock formation is around 266 metres thick at this point. The Bristol Geology Society describes the rock as: Splintery dark grey calcite and dolomite mudstones, pale grey oolitic, dark grey bioclastic and oncolitic limestones and some mudstones. Scattered cherts and silicified fossils in lower half. Sandy limestone at base in Bristol area. Deposited in a barrier/back barrier/shelf lagoon setting.
The Avon Gorge itself was formed much later, during the last Ice Age, when an ice sheet prevented the natural flow of the River Avon, causing it to divert and slowly erode the gorge we see today.
The house lies just north of the St Vincent Rocks Fault, on the southern side of Nightingale Valley, which borders a formation of Hotwells Limestone. Further to the north, the Avon Thrust Fault marks the northernmost end of Nightingale Valley. It is these “faults” (or fracture) in between the rock formations that resulted in the dry valley now known as Nightingale Valley. As a slide aside: there are no nightingales in this valley or the other Nightingale Valley in East Bristol.
The property we are concerned with lies just a few metres away from one of the most striking, if under-appreciated geological features within Nightingale Valley. What the caving community calls “Bloke’s Cave” but the National Trust rather more sensibly calls “Nightingale Valley Cave” lies just to the north of the property and runs partially under the road in front of the house. The last professional assessment (Quinn, 1999) says the following:
Altitude 100m, length 10m. This is a large rock shelter situated less than 10m below North Road and near the junction with Bannerleigh Road. The entrance is approximately 5m wide and 2m high; 4-5m from the entrance the cave suddenly narrows to a tight chamber.
This cave needs to be visited, surveyed and assessed.
This area is notable for having a number of caves, Skeleton Cave and Burwalls Cave being perhaps the best known of them. The Trust estimates the Burwalls Cave to be “Lower Palaeolithic to Unknown – 500000 BC? (between))” so it is likely the Nightingale Valley Cave is of a similar age. The last assessment of Burwalls also strong evidence for Palaeolithic occupation (Stone Age) and it is possible to speculate that the Nightingale Valley Cave may have been used as a form of shelter during this period as well.
The Dobunni and Burwalls Camp (650BC – 43AD approx)
Fast forward a few million years and we find people settled in the area, at the Stokeleigh, Clifton Down and Burwalls camps (also known as Burgh Walls, Bower Walls, or Bowre Walls), that date from 350BC. If the present day house had been around during the Iron Age (fully 550BC to 1AD), the window of bedroom five (2003 layout) would have looked out over the Burwalls settlement, a prominent hill fort occupied by the Dobunni people.
The house is just about positioned outside of the camp’s enclosure, by only a few metres. St Ambrose (the residence of the Catholic Bishop of Clifton) sits pretty much on top of where the Iron Age defences would have been. A mound in the grassy verge opposite the property is the remains of a rampart and one of the few above-ground indications that the fort was here. At the time of writing, this verge is not a scheduled ancient monument, nor on the National Trust’s register of historic sites. I have made some efforts to correct this.
It is likely that the the Dobunni created the “Leigh” in “Leigh Woods”. A “Leigh” is simply a clearing in a woodland, and although today’s property sites just outside where the fort would have been, it is likely that much of this area would have been pastoral from the Iron Age onwards.
Although both the Stokeleigh and Clifton camps are still easily visible today, the Burwalls Camp was largely destroyed to make way for the first houses built in Leigh Woods, around 1868. At one point, the camp enclosed an area of around seven acres, similar to the Stokeleigh camp which now sits in the National Trust section of Leigh Woods. An illustration in The History and Antiquities of Somersetshire (1839), indicates an outermost defensive ring consisting of a series of three earth banks with ditches in between.
Thankfully, George Alfred Wills had part of the camp mounds uncovered and preserved within the grounds of his house, Burwalls. They are still on private land but Burwalls Cave is now situated within the accessible National Trust-owned section of Burwalls Forest and can be reached on foot.
Image: Taken from “The History and Antiquities of Somersetshire; being a General and Parochial Survey of that interesting county.”
Written by the Rev. W. Phelps, A.B. F.S.A. Vicar of Meare and Bicknoller. Drawings credited as “J and JC Buckler, P Crocker, Esqrs and others”. Public domain work in the United Kingdom.
A = Burwalls Camp – a helpful illustration as this camp was destroyed around 1868 by the Leigh Woods Land Company, making way for the present day Victorian “villas”. It was a Dobunni era Iron Age hillfort. Some visible sections on the grounds of present day Burwalls House (private) and by the roadside on North Road (National Trust)
B = Clifton Down Camp – another Iron Age hillfort around the present day Observatory now owned by Bristol City Council
C = Stokeleigh Camp – a third fort from the same era, this one better preserved. It was saved from development through George Alfred Will’s purchase of Nightingale Valley, now in the hands of the National Trust.
The Dobunni held on to territory across much of the South West and retained a capital at modern day Cirencester (later occupied by the Romans). As well as the three Avon Gorge camps mentioned above, the tribe had forts at Kingsweston Down (later the site of a Roman villa and present day Kingsweston House), Maes Knoll (Dundry) and the site of present day Blaise Castle. Another situated within present day Knole Park, shared the same fate as Burwalls. With the sale of Knole Park House (Almondsbury) and its estate in the 1920s, developers flattened and built over the remains of a camp that had been previously had visible ramparts. There were likely others dotted around.