Norwood Ridge

The Norwood Ridge is an elevated area of south London contained within the London boroughs of Croydon, Bromley, Lambeth, Southwark and Lewisham. It aligns approximately south-southeast to north-northwest. Historically, it was part of the area covered by the Great North Wood that gave Norwood its name and was later the site of the relocated Crystal Palace at Sydenham Hill and nationally important telecommunications towers.

Physical Geography

The bedrock of the ridge is London Clay formation, part of the Thames Group, made up of clay and silt layers of the Palaeogene period, formed between 56 and 47.8 million years ago in what was a marine shoreline. This clay rises in the south at Selhurst in the borough of Croydon, through Grangewood Park, to its highest points in a band along the roads South Norwood Hill, Beulah Hill, Church Road, Crystal Palace Parade and Sydenham Hill before descending to variable lower elevations at Forest Hill and Honor Oak in the borough of Lewisham. Western spurs extend into the borough of Lambeth. The highest elevation of the ridge is 116 metres, around the southern end of Church Road and close to the site of the Croydon transmitter.
The elevated London Clay is overlain by a more resistant Claygate member, a sandier sub-unit of the London Clay formed between 56 and 48.1 mya, in beds of up to 16 metres depth which align with the ridge, running from South Norwood Hill to west of Forest Hill. On top of the Claygate beds, the highest points of the ridge consist of overlying superficial river deposits of sand and gravel of uncertain age and origin but which have been attributed to an ancient eastward-flowing river present in the Quaternary period, to a maximum age of 2.58 mya; deposits of the same group make up higher parts of Streatham up to Crown Lane. There are also Quaternary deposits of Head - poorly-sorted, slow-creep glacial hillwash - on the east and west slopes of the ridge either side of Crystal Palace Parade.
A 128.97-metre borehole was drilled at the Upper Terrace of Crystal Palace Park by Jubilee Gardens, just northeast of the junction of Crystal Palace Parade and Anerley Hill; the hole went through the superficial geology and Claygate beds almost to the base - below sea-level - of the London Clay formation in this area and was used to redefine boundaries between the geological layers.

Human Geography

On the ridge where Westow Hill meets Crystal Palace Parade stood the 'Vicar's Oak' until the 17th century which indicated where the parishes of Lambeth, Croydon, Camberwell and an isolated part of Battersea met. At approximately the same crossroads location is where the modern London boroughs of Lambeth, Southwark, Bromley and Croydon meet; such a boundary has been problematic regarding the provision of local services and utilities. The largest area remaining of the original North Wood is Dulwich and Sydenham Hill Woods whose flora indicate ancient woodland. Dulwich Upper Wood also contains an ancient remnant. As with other areas of London, local clay was used to manufacture bricks, such as at the brickfields between Holmesdale Road and Whitehorse Lane and at Pascalls by the junction of South Norwood Hill and Norwood High Street
The area was a recreational destination of Londoners travelling south; gipsies lived in parts of the wood on the ridge. The ridge is associated with water engineering, springs and spas, such as the 'medicinal' springs which became popular for visitors from the 17th century onwards at Sydenham Wells Park, Streatham Village and Streatham Wells as well as the later Dulwich Wells, Beulah Spa, Biggin Hill Spring (at Biggin Wood