ABSTRACT Bohemilla ( Bohemilla ) scotica Reed, 1914 and B. ( B. ) xesta sp. nov. are described from the middle Katian (around the Caradoc–Ashgill boundary in terms of the regional chronostratigraphical scheme) of the Girvan district of SW Scotland. Their occurrence in the Upper Whitehouse Subgroup of the Ardmillan Group is in the youngest recorded part of the range of the genus. Their association with a diverse deep-water trilobite fauna, including members of the cyclopygid biofacies, accords well with the earlier occurrences of the genus that first appeared in the Early Ordovician. The earlier history of Bohemilla was largely at higher latitudes and its occurrence at Girvan, and probably at a broadly equivalent stratigraphical level in Ireland, marks the extension of the range of the genus to the Laurentian margin of the Iapetus Ocean in the latest part of its history.
Ingham et al. (Wed,) studied this question.