Spore assemblages from the Silurian-Lower Devonian ‘Lower Old Red Sandstone’ deposits of the Lanark Basin of the Midland Valley of Scotland

The Lanark Basin is situated along the southern Margin of the Midland Valley of Scotland. It contains a series of Silurian inliers whose transitional marine to brackish to terrestrial sequences are unconformably overlain by Lower Devonian ‘Lower Old Red Sandstone’ deposits. Dispersed spore assemblages have been reported from terrestrial deposits towards the top of the Silurian sequences and are of early Wenlock age. Those from the Hagshaw Hills inlier have been reinvestigated and updated records reported herein. The first dispersed spore assemblage recovered from the ‘Lower Old Red Sandstone’ deposits that unconformably overlie the Silurian sequences is described. It is from the Greywacke Conglomerate Formation and is interpreted as being of Early Devonian (Lochkovian) age. This is concordant with previous radiometric age dates reported from associated volcanic rocks.