In the list of fossils from the Silurian rocks of the South of Scotland in the collections of the Geological Survey the two species of Ischadites, I. antiquus, Salter, and I. Königi, Murchison, are entered as occurring in the Llandovery rocks, while a third unnamed species is recorded from the Caradoc. In the list of fossils prepared by Mrs. Gray from the collection made by her from the Silurian rocks of the Girvan district, I. Königi is recorded from the Llandeilo beds of Balclatchie, I. antiquus from the Upper Llandovery of Penkill and the Middle Llandovery of Woodland Point, and I. sp. from the Middle Llandovery of Newlands. Nicholson & Etheridge mentioned only two specimens of Ischadites, one from Balclatchie and the other from Penkill; both were referred to under the name I. Königi, but it was remarked that one of them appeared to possess more the characters of I. antiquus. The first discovery of I. Königi in the Girvan area was made by Mr. Robert Gray and was noticed by Professor J. Young in 1868, and in 1876 the same author recorded it from Penkill in his “Catalogue of Western Scottish Fossils,” p. 13. Dr. Hinde gives both the localities, Balclatchie and Penkill, for the occurrence of I. Königi, but he regards the species I. antiquus as indistinguishable from it. The only other British species mentioned by this author (loc. cit.) is I. Lindströmi, Hinde.