I n an early edition of Siluria (1854) there is a figure of a specimen of Paradoxides Forchhammeri ? Angel., from the black slates of North Wales. In the third edition of the same work (1859) the same figure occurs, with the remark “locality unknown, probably from Pen Morfa, near Tremadoc, North Wales.” In this edition there is also a note with reference to the occurrence of this form, stating that “only one species of Paradoxides has yet been found in Wales; although the specimen is imperfect, Mr. Salter believes it to be identical with P. Forchhammeri of the alum slates of Andrarum in Scania.” In the last edition of Siluria (1867) the same figure is named Paradoxides Hicksii ; its locality is indicated as “near Dolgelly, North Wales;” and it is further stated that” this fossil has been found both at Dolgelly and in Pembrokeshire, about a hundred feet above the lowest black Lingula-slates.” Respecting the discovery of another form, Paradoxides Davidis , Salter, in Pembrokeshire, the late Mr. Salter has described this species, and named the locality whence it has been obtained*. In this memoir a Table is also given of the strata which make up the “Lingula-flags in Wales ;” and Mr. Salter has described the lower portion of this series as a “thick mass of black shales very uniform in its upper part, but with hard sandstones in the lower, probably accumulated in a deep sea.” The fossils of the Lower Lingula-flags are stated to be “ Lingulella , rare,