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Glasmullen Townland streamAntrim
Stream section at Glasmullen, south-west of Waterfoot, Co.Antrim, showing contact between medium-grained sandstones (below) and laminated mudstones at the top of Unit 5 of the Red Arch Formation.
Summary Full report
Site Type: Stream section
Site Status: PASSI
District: Moyle District Council
Grid Reference: D22052242
Rock Age: Devonian (Upper Devonian)
Rock Name: Red Arch Formation
Rock Type: Mudstone, Sand, Sandstone
Other interest: cross-bedding, No Data

Summary of site:

Unit 5 of this Devonian sequence is the topmost; for a general account of all units see Key Site 1148 ‘Devonian-Red Arch Formation; Cushendall to Red Arch, Glenariff’.

Unit 5 is the only unit not completely exposed on the coast, so this stream section in an abandoned chalk quarry is invaluable. The unit consists of very pale sandstones at the base, white to fawn with thin beds of red-brown mudstone. Above them, 3-4m of red-brown finely laminated mudstone abruptly appears with fine, green laminations throughout. Green mudstones often contain fossil plant spores, which can be important for dating purposes, but none was found in these rocks.

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