Below the Trias

Back in England William Smith was confronted with a problem. He found that along the eastern flanks of the central north-south Pennine Ridge and below his Red Marls (the New Red Sandstone), there is a distinctive succession and outcrop of what was called Magnesian Limestone and it, in turn, lay above the 'Coaliferous' strata. However, on the west side of the Pennines from the Solway Firth to the coast of Devonshire, the succession of red and brown sandstones along with pebble conglomerates extends right down to the coal-bearing strata without any intervening limestone. Again, the answer to the problem was not to be found in Britain but in the far east of the European mainland, where it faces the vast hinterland of Asia. The boundary is marked by one of the world's great geological features, the Ural Mountain chain, which extends practically all the way from the Arctic Ocean to the Caspian Sea. And it was a British geologist who carved out this new system of strata and period of geological time -Roderick Impey Murchison.

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