Cwm Twrch is a Site of Special Scientific Interest (SSSI) in Carmarthenshire, Wales.
SSSI Cwm Twrch SSSI is located on and around the Afon Twrch approximately north-east of Ystradowen, and covers .
The site is notable for its geology, where river erosion provides the best exposes the Amman Marine Band, a sedimentary layer showing a diverse fauna, which marks the Westphalian A – Westphalian B boundary in this Carboniferous rock strata.
See also List of Sites of Special Scientific Interest in Carmarthenshire
References
External links SSSI Citation for Cwm Twrch Citation map for Cwm Twrch Your Special Site and its Future - Cwm Twrch SSSI overview from Natural Resources Wales Cwm Twrch SSSI marked on DEFRA's MAGIC Map