Blisworth Limestone Formation relationship to the Jurassic ridge, to the west of Peterborough. (BGS sheet 157) Around Towcester it reaches a thickness of 9m. (Hains & Horton p. 85) Blisworth limestone is used as a building material, in particular as blocks of stone. Lilford Hall in Northamptonshire is made from Blisworth limestone. Blisworth Limestone Formation The Blisworth Limestone Formation is a geological formation primarily consisting of limestone deposited during the Bathonian stage of the Middle Jurassic, found in the Jurassic ridge which extends north and south through England. It was laid down in the shallows of the Jurassic sea and is part of
Netherton Tunnel Branch Canal was later converted to electricity and it is now unlit. The air vents that run along the line of the tunnel and provide ventilation, and a shaft of light into the canal, are known by the locals as "pepper pots", because of their shape. They are brick-lined and the openings are covered by an iron frame or grill. The wide bore and good ventilation mean that boats using the tunnel today are allowed to use the power of their internal combustion engines, which is prohibited in the narrower Dudley Tunnel. The tunnel cost £302,000 as opposed to the £238,000 estimate