In: The Silurian system, founded on geological researches in the countries of Salop, Hereford, Radnor, Montgomery, Caermarthen, Brecon, Pembroke, Monmouth, Gloucester, Worcester, and Stafford : with the descriptions of the coal-fields and overlying formations / by Roderick Impey Murchison, (1839)

In: The circle of the sciences : a cyclopaedia of experimental, chemical, mathematical, & mechanical philosophy, and natural history. The sections have been written by authors of great scientific eminence; amongst whom are: Professors Owen, Ansted, Tennant, and Young; Drs. Letheby, Bushnan, Scoffern, and others / ed. by James Wylde ; with an introductory discourse of the objects, pleasures, and advantages of science by Henry Lord Brougham, (1862-)