CRITIQUE OF DIACHRONISM, COMMUNITY DISTRIBUTION AND CORRELATION AT WENLOCK-LUDLOW BOUNDARY

This paper reviews conclusions reached by J. M. Hurst in a recent paper in Lethaia regarding abrupt, widespread deepening close to the Wenlock-Ludlow boundary as a result of possible eustatic or epeirogenically controlled transgression, and use of such an event as a means of stratigraphical correlation. Much of the benthic community evidence on which these conclusions are based is shown to be conflictory and the resulting correlations to be imprecise. Undoubted diachronism of the Much Wenlock Limestone Formation and overlying Lower Elton Beds is evident only between Dudley and Shropshire. Gradual deepening at this level in the Welsh Borderland appears to be a local reflection of tectonic movement. Wider regional evidence, from North America to the Anglo-Baltic area, rejects the view of a synchronous eustatic or epeirogenic transgression.