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
Blisworth opened on 21 May 1991. The by-pass runs to the west of the two villages, now following a newly created route from Tiffield. The road joins the M1 London to Yorkshire motorway at a new junction created at that time, 15A, at West Hunsbury, Northampton. From Northampton to Blisworth the by-pass closely follows the trackbed of the Blisworth to Northampton railway, long since closed. The new road makes a slight detour near the Northampton arm of the canal at the 'staircase' of locks near Rothersthorpe. The road's construction followed many years of long campaigns in the two villages. The London