The Riccarton and Raeberry Castle beds in Kirkcudbrightshire have hitherto been regarded as Wenlock in age, and the Hawick Rocks as Llandovery. Detailed mapping and revision of the graptolite faunas shows that the Raeberry Castle beds are Llandovery and the Riccarton beds Wenlock in age. On structural evidence the Hawick Rocks south of Kirkcudbright are considered to be younger than the Riccarton beds. The Riccarton beds in the area are formally defined as the Ross Formation and the Raeberry Castle beds as the Raeberry Castle Formation. Directional data suggest that the sediment forming the Raeberry Castle Formation was derived from the west and the sediment forming the Ross Formation and Hawick Rocks was derived from the north-east.