IV.—Note on the ‘Lower Tremadoc’ Rocks of St. David's, Pembrokeshire

Abstract

In the year 1866 Hicks and Salter recorded the occurrence of certain rocks in the neighbourhood of St. David's which they regarded as Tremadoc deposits. The beds appeared to them to rest conformably on the Lingula Flags, but when the rocks were compared with those of the Tremadoc area striking lithological differences were noticed. Accompanying the report was a list of fossils collected from the beds, and the fauna was so wholly unlike that of the North Wales deposits that the authors were led to conclude that the dissimilarity was due to the conditions under which the strata were deposited.