(Trias) The first period of the Mesozoic era between about 225 and 195 million years ago. In the early Triassic, arid conditions prevailed though later the climate became mostly temperate, but variable. The early conditions have resulted in fossils of the period being generally rare. The fossil lycopsid Pleuromonia found in Triassic sandstone is thought to be an intermediate form between the Lepidodendrales and the Isoetales. Members of the sphenopsid order Sphenophyllales became extinct at the beginning of the period. The now extinct order of the gymnosperms, the Bennettitales, arose in this period and common fossils are Bennettites and Williamsoniella. Members of the extinct order Caytoniales are found and the Ginkgoales are well represented in the Upper Triassic (e.g. Ginkgoites). See geological time scale , Permo-Triassic. |
