Much has been written on the subject of the physical and climatal conditions under which the Trias was deposited. Mention may be made of the work of Goodchild, 1896; Mellard Reade; Bonney, 1900, 1902; Lomas, 1907; and Bosworth, 1912. Their papers show a general concensus of opinion that the deposit took place under continental and desert conditions in an extremely arid climate. An important discovery made in 1899 by Mr. R. F. Martin near Mountsorrel, further finds at that place and near to it, and revelations made later at Mountsorrel itself, all seemed to the writer to give decisive confirmation to this conclusion. But doubt has been thrown upon the validity of some of this evidence, and it will be well to re-examine it.