The Carboniferous, Permian, and Triassic Rocks under the Glacial Drift in the North of the Isle of Man

Abstract

The whole of the Isle of Man, north of a line drawn due west from Ramsey, is covered with a thick mantle of Glacial Drift, forming a plateau rising, in some places, to a height of more than 100 feet above the sea. South of this, obviously a shore-line, the iceworn Ordovician massif of the island rises in u series of precipitous hills, culminating in Snaefell. The contrast, between the northern plain and the southern hills, is so marked, that it raises the question as to whether the Ordovician rocks are continued in the shape of a seaworn plateau, covered by Drift; or whether, in this concealed area, other and newer rocks occur, similar to those surrounding the Ordovician massif of the Lake District, of Carboniferous, Permian, and Triassic age. It was not improbable that the Coal-Measures of Whitehaven might extend beneath the sea in this direction. The question has been solved by a series of six borings, carried on under my advice from 1891 to 1898 by Messrs. Craine, and under the able direction of Mr. John Todd, to whom I am indebted ibr the journals from which the sections have been prepared. Of the specimens, from which the strata have been identified, some are in the Manchester Museum, Owens College, some in the Museum of Practical Geology, Jermyn Street, London, and some in the possession of the engineer at Ramsey. The borings are all close to the coast-line, starting from a plateau of sand and gravel, at about