Blisworth Limestone Formation today in the seas off the Bahamas (Kirkaldy p. 59). Much of it also contains marine shells, notably of oyster. Subsequently, the site was submerged less deeply so that the overlying Blisworth Clay was deposited in brackish conditions. (Gallois p. 20) The stratum is known as Blisworth Limestone because it was first studied at Blisworth in Northamptonshire when the Blisworth tunnel was being dug for what is now called the Grand Union Canal. The tunnel finally opened in 1805. Blisworth limestone is a generally thin but widely spread deposit in eastern England. It becomes thicker as one progresses southward from
Wansford Tunnel Wansford Tunnel Wansford Tunnel is a railway tunnel on the preserved Nene Valley Railway in Cambridgeshire. The tunnel is situated to the south of the village of Wansford, but just to the west of Wansford railway station. It was on the Blisworth to Peterborough line opened in 1845 by the London and Birmingham Railway. The line originally was double track. Today, however only a single track runs for its full length, the other track being used only as a siding. The tunnel is 616 yards long (but has no ventilation shafts) making this the fourth longest tunnel on a UK