Geology of Kent to uplift, sedimentation, and marine erosion. The Isle of Thanet was till recently (AD 960) an island, formed around a deposit of chalk. 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 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
Borough of Maidstone earliest in the county – that to Rochester and Chatham – was opened in 1728. In modern times, two motorways – the M2 and the M20 – pass to the far north of the borough and just north of the town centre of Maidstone respectively. The earliest line through Kent was built by the South Eastern Railway. It was not, however, built to pass through Maidstone: instead, a station was built at Paddock Wood railway station, then named "Maidstone Road", some six miles away. It was only in the period between 1844 (when that main line was connected by a