Kent coastline of Kent is continuously changing, due to tectonic uplift and coastal erosion. Until about 960, the Isle of Thanet was an island, separated by the Wantsum channel, formed around a deposit of chalk; over time, the channels silted up with alluvium. Similarly Romney Marsh and Dungeness have been formed by accumulation of alluvium. Kent's principal river, the River Medway, rises near East Grinstead in Sussex and flows eastwards to Maidstone. Here it turns north and breaks through the North Downs at Rochester, then joins the estuary of the River Thames as its final tributary near Sheerness. The Medway is
Worcester, Nashua and Rochester Railroad years later. The Commonwealth of Massachusetts acquired this portion of the right of way; in 2002 it was officially opened as the Nashua River Rail Trail. The one mile of track between Union Station in Nashua and an industrial park was abandoned finally in 1993. The W&N still survives between Ayer and Worcester, operated by Pan Am Railways whereby it is now designated as that railroad's Worcester Main branch. The line sees daily through-freight usage, permitting interchange at Worcester with CSX and Providence & Worcester Railroad. Worcester, Nashua and Rochester Railroad The Worcester, Nashua and Rochester Railroad was a railroad