SummaryThe Devonian brachiopod Tropidoleptus is recognized for the first time in South Africa. It is present in the lower part of the Witteberg Group at four widely separated localities. Data regarding the stratigraphical range of the genus elsewhere, combined with information on recently described fossil plants and vertebrates from underlying strata of the upper Bokkeveld Group, suggest that a Frasnian or even Givetian age is reasonable for the lower part of the Witteberg Group. The recognition of Tropidoleptus in a shallow water, near-shore, molluscan association, at the top of the South African marine Devonian sequence, is similar to its occurrence in Bolivia, and suggests a common Malvinokaffric Realm history of shallowing, prior to later Devonian or early Carboniferous non-marine sedimentation. It is noteworthy that Tropidoleptus is now known to occur in ecologically suitable environments around the Atlantic, but is absent from these same environments in Asia and Australia. Tropidoleptus is an excellent example of dispersal in geological time — first appearing in northern Europe and Nova Scotia, then elsewhere in eastern North America and North Africa, followed by South America and South Africa, while continuing in North America.
I.—History of the Names Cambrian and Silurian in Geology