Engineers working on Britain’s new high speed railway have discovered an ancient, sub-tropical coastline dating back 56 million years. The rare discovery was made at a site in Ruislip when HS2’s ground investigation team unearthed a previously unknown material, located up to 33 metres below the surface.
The layer of black clay, which HS2 Ltd has named the ‘Ruislip Bed,’ is thought to have been formed from densely wooded marshes on the edge of a sub-tropical sea. HS2 Ltd made the surprising find while investigating ground conditions in the area, prior to the construction of the Northolt Tunnel – a 14km tunnel which will run from West Ruislip to Old Oak Common.
HS2 has been investigating the ground at around 8,000 locations along the first phase of HS2, from London to the West Midlands.
The initial ground investigation programme on Phase One of the railway, from London to the West Midlands, will be largely complete by the end of March 2018. This will be followed by supplementary, targeted investigations, led by HS2’s main works contractors.