An Upper Llandovery Konservat-Lagerstatte in a depositional context: the Pentland Hills Eurypterid Bed, Midlothian

Re-excavation and detailed logging of the sedimentary sequence which includes the Eurypterid Bed on the Gutterford Burn, Pentland Hills, Midlothian, has clarified the depositional setting of this Silurian Konservat–Lagerstätte. The relative positions of the Gutterford Burn limestones, beds yielding dendroid graptolites and the Eurypterid Bed itself have been identified. Clay bands occur at a number of horizons throughout the 23 m of logged section, but the most important of these enclose the distinctive lithology of the Eurypterid Bed. Exceptionally preserved fossils typically occur within a volcanic ash-rich claystone which was deposited below storm wave-base in a fully marine setting. Depositional style, presence of in situ corals and the presence of volcaniclastic input all indicate similarity to the sequence exposed around the Deerhope Coral Beds. The stratigraphy of the North Esk Inlier is revised t o take into account these new findings. The boundary between the Reservoir Formation and the overlying Deerhope Burn Formation is defined as lying at the base of the first calcareous sandstone on the Gutterford Burn section.