PALAEOGEOGRAPHICAL DISTRIBUTION OF THE PECTINID GENUS WEYLA (BIVALVIA, LOWER JURASSIC)

The global distribution of the Early Jurassic pectinid bivalve Weyla (s. str.) is reviewed stratigraphically, and a list of all known nominal species is given. Confirmed Hettangian occurrences of the genus seem to be restricted to Canada, but by Sinemurian times it had spread along the Pacific coasts of the Americas, where it persisted through to Toarcian times. Further Pliensbachian occurrences have been revealed in France, Spain and Morocco, but no certain Toarcian records have so far been recognized from Europe. Whilst persisting in northern Africa, by this time it spread also to Turkey, Saudi Arabia, Pakistan, Kenya and Madagascar. These occurences support the idea of a shallow marine connection between the western Tethys and the eastern Pacific as early as Pliensbachian times, with the presence of a Mid-Atlantic seaway as the most plausible alternative hypothesis. © 1979.