Mithil Brook and Cwm Blithus
Also within
Geology & landscape
Geological Period: Silurian · Rock Type: Siltstone
Description
Description Located approximately 5 km west of New Radnor, this site displays a nationally important sequence of rocks of early to mid-Ludlow (Gorstian) age, ranging from the Upper Llanbadarn Formation, through the Bailey Hill Formation and into the succeeding ‘Striped Flags’. The Bailey Hill Formation consists of a sequence of calcareous sandy siltstone beds which display a magnificent array of slump and slide structures, predominantly comprising recumbent folds, together with sole marks, convolute lamination and ripple cross-lamination. These structures record penecontemporaneous soft-sediment deformation caused by down-slope slumping towards the north-west. Such features are rare on a regional scale within the Silurian of the Welsh Basin. Palaeogeographical reconstructions indicate that the Bailey Hill Formation accumulated on a NW-dipping palaeoslope along the south-eastern flank of the Montgomeryshire Trough, part of the Welsh Basin, the margin of which was defined by the Church Stretton Lineament. In this respect, the locality represents one of the relatively few sites of Ludlow age that have an off-shelf aspect. Remarks: The site is described in the Geological Conservation Review volume entitled ‘British Silurian Stratigraphy’ (Aldridge et al., 2000).