The tilted Carboniferous Limestone in the eastern Mendips is transected by a remarkably planar unconformity, formed by the Bajocian transgression. The unconformity is riddled with borings, of which the most common ichnogenus, Trypanites, reaches densities in excess of 10 per cm- , Based on a marked bimodal size distribution they are classified as two ichnospecies: T. weisei (Mägdefrau, 1932) and T. fosteryeomani (ichnosp. nov.). The larger of these, T. fosteryeomani, is seen to penetrate to depths exceeding 400 mm. Central tubes observed in T. weisei, thought to represent a mould of the body of the Trypanites animal, are described. From these observations inferences concerning the mode of life are made.