Geography of Kent and Dungeness have been formed by accumulation of alluvium. Kent's principal river, the River Medway, rises near Edenbridge and flows some 25 miles (40 km) eastwards to a point near Maidstone, when it turns north. Here it breaks through the North Downs at Rochester before joining the River Thames as its final tributary near Sheerness. The river is tidal as far as Allington lock, but in earlier times cargo-carrying vessels reached as far upstream as Tonbridge. The Medway has captured the head waters of other rivers such as the River Darent. There are other rivers in Kent, most notably the
Buffalo, Rochester and Pittsburgh Railway R&P; this proved to be a bottleneck, and the company which succeeded the Rochester and Pittsburgh Railroad Company, the Buffalo, Rochester and Pittsburgh Railway, built a forty-mile detour, opening it in 1893. While the R&P was expanding on its south side, it also built on the north end. Using the Rochester and Charlotte, the Buffalo, Rochester and Pittsburgh, and the Perry Railroad as construction companies, it brought much greater capability to the old RS&L yard at Lincoln Park and extended its line to the coal pier on the Genesee River at Lake Ontario (Charlotte). Succumbing to over-expansion, the R&P went