Deposition of Peat from Aqueous Suspensions; Natural Occurrence of Stalactitic and Related Forms

Abstract

IN the course of study of a line of caverns at Ystradfellte, Breconshire, described previously1,2 the occurrence of a hitherto unrecorded type of stalactite formation was noted. Most of the formations are unconsolidated, conical in shape and hang vertically from the Millstone Grit caprock forming the roofs (Fig. 1). They range in length from 0.4 to 30.0 cm and in mean diameter from 0.1 to 5.5 cm respectively, and are composed of a non-fibrous size-fraction of blackish brown peat transported from the surface peat bog overlying the grit. In most cases cross-sections reveal a series of concentric growth rings. These are co-axial with the core when it is present. The formations occur in two main types: joint-orientated lines extending across the roofs (type I); randomly distributed and isolated formations (type II).