Geology
A Locally Important Geological site
Some clues to the pre-historic origins of the landscape can still be seen at the Buckthorne Cutting. These include its geology, its vegetation and historic accounts of the landscape in the past. The entire Cutting is designated as a LIGS (Locally Important Geological Site). This means it has borough-wide importance due to the Septarian nodules found in situ. This is the only place that you can see them on the surface in London.
Septarian nodules are a concretion of rock, formed from calcium-rich clay that hardens into a nodule. The alternating wetting and drying of the nodule results in calcite-filled cracks which radiate outwards from the centre. These angular cracks are called ‘septa’ or ‘septaria’ (from the Greek word ‘septum’) meaning partition. Often fossils are also found in the nodule. Septarian nodules come from the Cretaceous period and formed anywhere between 50 to 70 million years ago. They were once used in Roman wall building.
The presence of Septarian nodules, reeds and ferns growing along a linear route most likely points to the presence of underground springs. Other clues to suggest an underground water source are the presence of an expansive reedbed on what is probably a high ridge line.
This reedbed is thought to be linked to an old pond which existed before the Croydon Canal (1809-1836) cut through it. A large pond is just visible on a 1788 plan showing the proposed route for the Canal through Brockley Green and Christ’s Hospital land.
Peat of the pond
Between 1805 and 1809 when the Croydon Canal was dug, David Hughson documented the findings in his book “London; Being an accurate history and description of the British Metropolis“. Hughson’s account talks of peat near the old pond (now the reedbeds). In most cases peat formation will have begun in the pre-historic period.
Peat’s acidic and anoxic (oxygen depleted) conditions mean that it preserves ancient organic remains and cultural organic objects, such as textile and leather much more easily as they do not decompose.
Pre-historic fossils
Hughson’s account of a fossil horizon of bivalve shells is another connection to the landscape’s prehistoric past, when this land was once under the sea. He writes:
‘[T]he ground begins to rise up towards Brockley Green and the first thing observable in the newly cut banks is a curious stratum of a yard thick consisting almost entirely of small bivalve shells’
Vegetation: Giant Horsetail
Giant Horsetail is abundant at the Eddystone Road end of the Buckthorne Cutting. Giant Horsetail is on the list of scarce plants in London and is considered a living fossil, as it is a plant that flourished over 350 million years ago.
A curious inn sign
There is a small inn located more or less on the route of the Roman Road to the east of the Buckthorne Nature Reserve. On medieval maps it is called ‘The Castle’ or The Castle Ale House’. Later this picturesque old hostelry came to be known as the Brockley Jack, reputedly named after Jack Cade, leader of the 1450 Kentish Uprising and visitor of the pub. The pub is still there today, under the same name, although now replaced by a late Victorian building.
An account in 1912 by Walter Besant in his book, ‘London South of the Thames‘ suggests that a mammoth bone displayed in front of the inn had been dug up along the cutting. This event supposedly took place during the the excavations of the Croydon Canal in 1836 to make way for the railway line.
“The taproom and the whole architecture of the place with its old buildings are curious, and the sign nailed to the stump of an old elm in the yard is painted on a mammoth’s bone which was dug up in the railway cutting behind the house.”
Most other accounts suggest the sign was actually a whale bone. This is feasible, as at the time there was a whale factory in Deptford. The bone could have made its way from Deptford down the Croydon Canal. Another plausible explanation is that travellers brought it to the Inn as an exotic artefact. The whale’s blubber and bones were used in Victorian soaps, paints as well as domestic and street lighting. The Deptford whale factory workers may well have frequented the Brockley Jack. These various accounts and stories associated with the bone, clearly create intriguing narratives about the landscape’s cultural origins.