Cf. Arnold R. Mountford, The Illustrated Guide to Staffordshire Salt-Glazed Stoneware, London, 1971, fig. 136 for three saltglaze examples and mention of an unglazed biscuit cover excavated at the Fenton Vivian site in 1969; see also Peter Walton, Creamware and other English Pottery at Temple Newsam House Leeds, London, 1976, fig. 423 for a creamware example with a pierced cover and cow finial; and Robin Reilly, Wedgwood, vol. I, p. 152, fig. 96 for a basket-moulded example with a coloured glaze