On the Discovery of Trilobites in the Upper Green (Cambrian) Slates of the Penrhyn Quarries, Bethesda, near Bangor, North Wales
- 1 February 1888
- journal article
- Published by Geological Society of London in Quarterly Journal of the Geological Society
- Vol. 44 (1-4), 74-78
- https://doi.org/10.1144/gsl.jgs.1888.044.01-04.10