. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Goniatites Listeri, Martin sp. Avicula papyracea, Goldf. (Pecten papyraceus, Sow.) No similarly intercalated layer of marine shells has been noticed in the neighboring coal-field of Newcastle, where, as in South "Wales and Somersetshire, the marine deposits are entirely below those containing terrestrial and freshwater remains.* Clay-iron-stone.—Bands and nodules of clay-iron-stone are common in coal-measures, and are formed, says Sir H. De la Beche, of carbon-
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Goniatites Listeri, Martin sp. Avicula papyracea, Goldf. (Pecten papyraceus, Sow.) No similarly intercalated layer of marine shells has been noticed in the neighboring coal-field of Newcastle, where, as in South "Wales and Somersetshire, the marine deposits are entirely below those containing terrestrial and freshwater remains.* Clay-iron-stone.—Bands and nodules of clay-iron-stone are common in coal-measures, and are formed, says Sir H. De la Beche, of carbon- ate of iron mingled mechanically with earthy matter, like that con- stituting the shales. Mr. Hunt, of the Museum of Practical Geology, instituted a series of experiments to illustrate the production of this substance, and found that decomposing vegetable matter, such as would be distributed through all coal strata, prevented the farther oxidation of the proto-salts of iron, and converted the peroxide into protoxide by taking a portion of its oxygen to form carbonic acid. Such carbonic acid, meeting with the protoxide of iron in solution, would unite with it and form a carbonate of iron; and this mingling with fine mud, when the excess of carbonic acid was removed, might form beds or nodules of argillaceous * Phillips; art. " Geology," Encyc. Hetrop., p. 592. f Memoirs of Geol. Survey, pp. 51, 255, & Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lyell, Charles, Sir, 1797-1875. New York, D. Appleton and co.
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
