On the presence of probable Upper Stephanian beds in Ayrshire, Scotland

Abstract

In the first issue of the Scottish Journal of Geology (January 1965) an account of basal New Red Sandstone rocks in south-west Scotland was published by W. Mykura, who indicated a rather strong diachronism at the base of these deposits, reaching downwards into Westphalian D in Ayrshire. Evidence for a Westphalian D age appeared to be found in a number of plant impressions collected by the Geological Survey and identified by W. G. Chaloner. An independent opinion on this flora was sought from the present author, who gave his own tentative identifications with comments on the various floral elements examined. His general conclusion was that the material collected appeared inadequate for a precise age determination, and that the floral assemblage might fit any age from Westphalian D to Autunian. Unfortunately, he was quoted in the published paper as having confirmed Dr Chaloner’s findings; thus implying complete agreement as to plant identifications as well as the Westphalian D age determination. Differences in opinion on both aspects did in fact occur. In view of the stratigraphic importance of the occurrence, and responding to a plea for more material to be collected, Mr Mykura kindly made available a new collection of plant impressions from the same locality in the bed of the river Ayr. Among these specimens, obtained by Messrs P.J. Brand and D. K. Graham (Geological Survey) from a horizon low in the Mauchline Volcanic Group (Mykura 1965), a terminal fragment of a pinna of Odontopteris ( Mixoneura ) subcrenulata (Rost) was found. This . . .