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
Maidstone the river to allow clothes to be rinsed in the cleaner water away from the banks. Neolithic finds have revealed the earliest occupation of the area, and the Romans have left their mark in the road through the town and evidence of villas. The Normans set up a shire moot, and religious organisations established an abbey at Boxley, hospitals and a college for priests. Today’s suburb of Penenden Heath was a place of execution in medieval times. Maidstone played a key role during the Peasants' Revolt of 1381. The rebel priest John Ball had been imprisoned there and was freed