The Permo-Triassic Desert Environment

Abstract

It is usually difficult to separate clearly the Permian system from the Triassic in Britain. The Permian is regarded as the last period of the Upper Palaeozoic era and the Triassic as the first of the Mesozoic era because of a considerable difference in the fossil faunas seen where these periods are represented by fully marine strata ; the Permian fauna is broadly reminiscent of the Car­boniferous, while the Triassic fauna is in many respects a foretaste of the Jurassic. In Britain both periods are almost everywhere represented by non-marine and poorly fossiliferous deposits ; even where marine Permian occurs it has a restricted and not very typical fauna. Hence both periods are often lumped together as the New Red Sandstone—the group of dominantly non-marine strata coming above the Carboniferous just as the Old Red Sandstone is the group of dominantly non-marine strata coming below it.