Rochester, Kent the Blackheath Beds of sand and gravel. As a human settlement, Rochester became established as the lowest river crossing of the River Medway, well before the arrival of the Romans. It is a focal point between two routes, being part of the main route connecting London with the Continent and the north-south routes following the course of the Medway connecting Maidstone and the Weald of Kent with the Thames and the North Sea. The Thames Marshes were an important source of salt. Rochester's roads follow north Kent's valleys and ridges of steep-sided chalk bournes. There are four ways out of
Zumbro River The South Fork Zumbro River, long, rises about east of Hayfield in southern Dodge County and flows generally eastwardly into Olmsted County, where it turns northward at Rochester and flows into southwestern Wabasha County. The South Fork's course through Rochester has been channelized as part of a flood control project. It is dammed in Wabasha County, by the Lake Zumbro Hydroelectric Generating Plant to form Lake Zumbro. The Middle Fork Zumbro River, long, rises in northeastern Steele County, about west of West Concord and flows generally eastwardly through northern Dodge, southwestern Goodhue and northeastern Olmsted counties, past Pine Island and