, otherwise known as St Peter's Pool, in Bourne. The Wellhead is a natural artesian spring, rising from the limestone some below the land surface. It once formed the source of the water defences for Bourne Castle as well as the power for the town's three mills. From the Wellhead, a branch flows to the east, along the southern edge of the castle site, while another flows north, then east and south, enclosing the castle site and Wellhead Gardens to rejoin the first branch near Baldock's Mill. A culvert carries the water under South Street, and it flows along the edge of Church Lane, where it is crossed by a small cast-iron bridge with gates, providing rear access to Bourne Eau House. It carries the date 1832. On the other side of Church Lane is the parish church of St Peter and St Paul, a grade I listed structure that was originally the chapel for an Arrouaisian order of Canons founded in 1138. At the north end of Church Lane, another culvert takes it under the gardens of the vicarage. This culvert and the South Street culvert are quite old, since they appear on the 1888 Ordnance Survey map. When the river resurfaces, if turns to the south, running behind the church building and then to the east along the back of gardens belonging to houses on Coggles Causeway. A lengthy culvert carries it under the Abbey Lawn complex and Victoria Place. This culvert is more recent, as it was built in the 1960s when the recreation ground became the Abbey Lawn sports complex. Before the culvert was built, the railway line to crossed the river near to where the culvert starts. It passes under Queen's Bridge, and then runs parallel to Eastgate. Half way along Eastgate, the channel becomes much wider, where it formed the terminal basin for the Bourne Eau when it was navigable. The Roman Car Dyke, now reused as a drainage channel, originally ran though the town, passing along the west side of Queen's Bridge, but a modern channel joins the southern section to the basin, on the north bank of which is the Anchor Inn, a small grade II listed public house dating from the 18th century. The A151 Cherry Holt Road crosses the waterway at May's Sluice, and then it enters South Fen, where it is joined by another channel linking to the Car