Appendix-The First British Primordial Fossil

Allen, P. M., & Jackson, A. A. 1985. Geology of the Country around Harlech. Memoir of the British Geological Survey, Sheet 135 with part of 149, xii + 112 pp. London: H.M.S.O.

Huxley, T. H., & Etheridge, R. 1865. Catalogue of the Collection of fossils in the Museum of Practical Geology, lxxix + 381 pp. London: H.M.S.O.

Marcou, Jules. 1888. Palaeontologic and stratigraphic "Principals" of the adversaries of the Taconic. American Geologist 2: 10-24, 67-88.

Murchison, R. I. 1854. Siluria, the history of the oldest known rocks containing organic remains, with a brief sketch of the distribution of gold over the Earth. John Murray, London.

Ramsay, A. C. 1866. The geology of North Wales. Memoir of the Geological Survey of Great Britain, 3: vii + 381pp., 28pls.

Salter, J. W. 1853. On the lowest fossiliferous beds of North Wales. Report of the twenty-second meeting of the British Association for the Advancement of Science, Belfast, 1852. Notices and abstracts of miscellaneous communications to the sections, pp. 56-58.

Salter, J. W. 1863. On the discovery of Paradoxides in Britain. Quarterly Journal of the Geological Society of London, 19: 274-277.