Sowerby, J. De C. (1839). Fossil shells in the lowest beds of the Old Red Sandstone, pl. 3. In: Murchison, R. I. (Ed.) The Silurian System, Founded on Geological Researches in the Counties of Salop, Hereford, Radnor, Montgomery, Caermrthen, Brecon, Pembroke, Monmouth, Gloucester, Worcester, and Stafford. Part II. John Murray, London, pp. 602-604.
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Sowerby, J. De C.
1839
Fossil shells in the lowest beds of the Old Red Sandstone, pl. 3. In: Murchison, R. I. (Ed.) The Silurian System, Founded on Geological Researches in the Counties of Salop, Hereford, Radnor, Montgomery, Caermrthen, Brecon, Pembroke, Monmouth, Gloucester, Worcester, and Stafford. Part II