Memoirs of the Geological Survey of England and Wales. ...

abundant accumulations animals appear Arenaceous shale argillaceous limestone Argillaceous shale Argillo-arenaceous shale beneath Black Bramerton Bristol Britain British Seas Brown Builth calcareous calcareous matter carbonaceous Carbonaceous shale carbonate carbonic acid carboniferous limestone Celtic coal beds coal field coal measures coast conglomerate copper Coralline crag corals Cornwall denudation deposits detrital detritus Devonian district dolomitic drift European Seas fauna feet flora formed fossil fossiliferous Fusus granite gravel gray argillaceous gray limestone gray sandstone Huel igneous igneous rocks Ireland ironstone land lias lime Linnæus Llandilo lower magnetic mammaliferous crag marine mass Mendip Hills mines Monmouthshire nodules of ironstone northern observed old red sandstone older rocks organic remains pebbles Pembrokeshire peroxide of iron plants portion quartz red crag Red marl sand sheet Silurian Silurian rocks slates South Devon South Wales southern species Stigmaria strata thickness thin beds trappean Underclay upper Vein