Strata of late Visean (P1c and P2) and early Namurian (El and E2) age that crop out on the northern and eastern flanks of the Derbyshire Dome have yielded trilobites from several horizons in the Monsal Dale Limestones Formation (dark lithofacies), the Eyam Limestones Formation, the Longstone Mudstone Formation and the lower part of the Edale Shale Group. Certain levels are crowded with disarticulated exoskeletal parts, accompanied by some articulated specimens. Paladin is the most widespread genus in these formations, both geographically and stratigraphically, with Cummingella, Baliothyreus gen. nov. and Eocyphinium having more limited distributions. The dark lithofacies at the top of the Monsal Dale Limestones Formation is established as the type lithology for Paladin bakewellensis Osmólska, Eocyphinium seminiferum (Phillips) and for Martin’s ‘Entomolithus Onicites (Derbiensis)’, now referred to Paladin. In this paper, Paladin derbiensis (Phillips), P. bakewellensis Osmólska, P. eakringensis Osmólska, Baliothyreus becki gen. et sp. nov. and B. fissisolanum gen. et sp. nov. are described. The Paladin species contrast with those present in coeval strata in the Askrigg Block and farther north, in north and south Wales, and in the Bristol district; they appear to be restricted to Derbyshire and the adjacent East Midlands. Baliothyreus has not been found outside Derbyshire.