Micropalaeontological evidence on the age of the Clara Group (South-East Ireland)

Correlation problems of metamorphosed Pre-Cambrian rocks in Wales and S.E. Ireland

“…Tremlett (1959) re-mapped the south-west end of the outcrop as a faulted complex of Ordovician, Cambrian and Pre-Cambrian members. New evidence for the Cambrian age of the Clara Series of slates and mudstones was obtained by the discovery of brachiopods and this has been supported by the microfauna (Downie & Tremlett 1968); however, the relation of the Oldhamiabearing localities listed by Kinahan (1887) is not discussed. This Series overlies rocks which were earlier folded isoclinally on ENE axes with the development of axial-plane slaty cleavage in the argillaceous bands and local Metamorphosed Pre-Cambrian, Wales and S.E.…”

Lower Cambrian palynomorphs from Howth, Co. Dublin

“…Simple sphaeromorph acritarchs in a very poor state of preservation were reported by Downie and Tremlett (1968) from around the southern part of the Bray Group outcrop in Co. Wicklow. They tentatively suggested a Cambrian age, although evidence from associated inarticulate brachiopods had also to be taken into account; the rocks from which the assemblages came are now assigned to the Ribband Group (Bruck and Reeves 1976 p. 60).…”

“…Within the last decade several attempts have been made to extract acid-resistant microfossils (palynomorphs) from Irish Cambrian rocks, and it is clear that this method holds promise for more accurate dating of at least parts of the succession than does any other palaeontological means. Simple sphaeromorph acritarchs in a very poor state of preservation were reported by Downie and Tremlett (1968) from around the southern part of the Bray Group outcrop in Co. Wicklow. They tentatively suggested a Cambrian age, although evidence from associated inarticulate brachiopods had also to be taken into account; the rocks from which the assemblages came are now assigned to the Ribband Group (Bruck and Reeves 1976 p. 60).…”