Abstract
Synopsis: Revision of the stratigraphy and faunas of the High Mains Formation at Girvan, SW Scotland indicates the presence of two distinctive shelly faunas, both interpreted as associations of the widely documented terminal Ordovician Hirnantia fauna; these occurrences confirm the correlation of the formation with the latest Ashgill Hirnantian Stage. Both sediment and faunal content may be taken to indicate a gradual regression of the late Ordovician sea in this area.