Geography of Sheffield county, from bituminous (ideal for domestic heating) to "Thick Coal", of a semi-anthracitic quality, appropriate for use in iron-smelting and in engine furnaces. Associated with the Upper Coal Measures were valuable iron ore deposits, occurring in the form of nodules. Large quantities of locally occurring fireclay were also exploited, as well as ganister (a clay used to make refractory furnace linings). The city of Sheffield derives its name from the River Sheaf which Until the 17th century was written as "Scheth" or "Sheath". Sidney Oldall Addy equates the origins of this word with the Old English "shed" (as in "water-shed")
English River (Iowa) in extreme northwestern Washington County. The English River then flows generally eastwardly for about , past the town of Riverside. It joins the Iowa River in northeastern Washington County, south of Iowa City. The North English River is the longer of the two forks. It rises just south of Grinnell in western Poweshiek County and flows generally east-southeastwardly through Iowa County, past the town of Guernsey. In Iowa County it collects two minor tributaries, the Deep River and the Middle English River, both of which rise in Poweshiek County and flow eastwardly for short distances. The Deep River is a