Abstract
The selection of the base of the Monograptus uniformis zone as the new Silurian-Devonian boundary as proposed by C. H. Holland (for reference, see this Bibliography Vol. 31, No. 3, 18 E67-02281; see also No. 9, 18 E67-08162) is examined. It is felt that there is no need to establish a new boundary until a datum horizon is found that meets more widespread international agreement and that a boundary based essentially on graptolite species is not of wide enough applicability.