[Letters to Editor]

Abstract

PROF. MARSHALL'S clear statement of the palæontological difficulties in this case should stimulate the search for further fossiliferous horizons. The Ordovician and Gotlandian beds of the British Isles were laid down in many places “during the continuance of uniform physical conditions and in direct continuous succession”; none the less, two systems have been conveniently maintained. The unwieldy “Karroo system” of South Africa would no doubt be split up were marine representatives of its strata available close at hand.