Geology of the Country around Liverpool

Abstract

IN this work Mr. Morton has entirely re-written the “Geology of the Liverpool District,” first published in 1863, by the light of the various discoveries made since that time, and especially of the Geological Survey maps and memoirs. He has succeeded in making a compact and well-printed hand-book, which will be of great service to the students of the local geology. The area described extends to about 20 miles from Liverpool on every side, excepting the sea on the west. The strata which he describes range from the Upper Silurians of the Vale of Clwyd through the Carboniferous, Permian, and Triassic rocks, down to the recent alluvia. To a geologist the chapter relating to the Carboniferous rocks of North Flintshire and the Vale of Clwyd will be of great interest, as it shows the thinning off of the strata as they approach the ancient Carboniferous land of North Wales. The Carboniferous Limestone, over 3000 feet thick in North Lancashire, is reduced to 1700 feet in North Flint and the Vale of Clwyd; while the Yoredales and Millstone Grits, over 9000 feet thick between Clitheroe and Burnley, are represented by the Cefn-y-Fedw Sandstone, 370 feet. The Lower and Middle Coal-measures, too, of South-West Lancashire, 31 8o feet thick, have dwindled down to no more than 1ooo feet as they approached the Welsh Silurian Hills. It is therefore obvious that the Snowdonian area was dry land while the Carboniferous sea occupied the areas of Lancashire, Derbyshire, and Cheshire, and that it also overlooked the forest-covered morasses, now represented by the coal-seams. of the same region in the Upper Carboniferous age. In the table of the rocks (p. 6) Mr. Morton gives 300 feet as the thickness of the Millstone Grit in South-West Lancashire. It is probably much more than this, and not much less than 2000 feet. Mr. Morton also, we may remark, understates the thickness of the Keuper Marls, which he puts down at 400 feet (p. 75). In the Lancashire and Cheshire plain it is 700 + feet, and is estimated by Prof. Hull at 3000 feet. Geology of the Country around Liverpool. By G. H. Morton Second Edition. (London: Philip and Son, 1891.)