Terrestrial plant microfossils from Silurian inliers of the Midland Valley of Scotland

Palynomorph assemblages comprising sporomorphs (cryptospores and miospores) and plant fragments (cuticle-like sheets and tubular structures) were recovered from red-bed sequences in the Lesmahagow, Hagshaw Hills and North Esk inliers from the Midland Valley of Scotland. The assemblages all indicate an early Wenlock age and probably belong to the chulus-nanus Spore Assemblage Biozone. The cryptospore taxa Cheilotetras caledonica gen. et sp. nov. and Pseudodyadospora petasus sp. nov. are proposed, and Tetrahedraletes is emended. The palynomorph and plant microfossil assemblages consist of entirely land-derived forms except in the North Esk inlier where rare acanthomorph acritarchs were recovered from a single horizon. Palynology thus provides additional evidence that the deposits in the Eesmahagow and Hagshaw Hills inliers accumulated in a non-marine environment, whereas a brief marine incursion interrupted terrestrial fluviatile deposition in the North Esk inlier. This report describes rare examples of Silurian palynomorph assemblages of entirely land-derived forms.