An Early Devonian (Lochkovian) microflora from the Freshwater West Formation, Lower Old Red Sandstone, southwest Wales

The Lower Old Red Sandstone deposits occurring to the south of the Ritec Fault on the Pembroke Peninsula in southwest Wales are very poorly age-constrained. Two moderately well-preserved spore assemblages have been recovered from the Freshwater West Formation, locally the highest division of the Milford Haven Group. These assemblages contain both cryptospores and trilete spores, with the latter group being dominant. They essentially represent a single microflora which is assigned to the middle part of the Emphanisporites micrornatus-Streelispora newportensis (MN) Spore Zone and is considered to be of Early Devonian (mid-Lochkovian) age. A new cryptospore species Qualisaspora sinuata and a new trilete spore species Dictyotriletes williamsii are described. The microflora is correlated with similar assemblages from the Dittonian of the main Anglo-Welsh Basin. Locally, the new biostratigraphic data constrain the age of the rich ichnofauna of the Freshwater West Formation and also date the influx of coarse clastic sediments into the basin following the sedimentary quiescence represented by the underlying Chapel Point Calcrete.