Review of the Ordovician palaeoenvironments of shelly fossils, including molluscs, of the Southern Uplands of Scotland

ABSTRACT The Lower Palaeozoic successions of the Southern Uplands of Scotland are well known for graptolitic shales such as those of Dob’s Linn and Hartfell Score. Less well known are the Ordovician shelly fossils, predominately preserved in mudstones and conglomerates of the Sandbian Kirkcolm Formation at Kilbucho and Wallace’s Cast. Rare carbonate facies from the Wrae Limestone within the Tweeddale Member, Shinnel Formation preserve limestone olistoliths containing probable shelly faunas and conodonts from an otherwise unknown source. Trilobites, brachiopods and conodonts from the Southern Uplands have been the subject of some recent research, but other shelly faunas have received less attention. These include the mollusc faunas, consisting mainly of bivalves and gastropods. A review of the mollusc fauna supports faunal evidence from brachiopods that the Kirkcolm Formation was close to Pomeroy, Tyrone and sampled deeper water environments than was originally thought.