Prattware
"A type of course moulded lead-glazed white earthenware introduced in the 1790's, decorated with a range of high-temperature underglaze colours, including cobalt-blue, copper-green, iron-orange and antimony-yellow--these having been used previously as the basis for polychrome delftware. The misleading collectors' term 'Pratt' arose solely because of a handful of marked pieces, but it was mass-produced also in Yorkshire at, for example, the Leeds Pottery and by Wedgwood and Co. of Ferrybridge."
Source: Pg. 227 "English Pottery 1620-1840 by Robin Hildyard"