. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Bed of indusial limestone, interstratified with freshwater marl, near Clermont (Kleinschrod). We may often observe in our ponds the Phryganea (or Caddis-fly), in its caterpillar state, covered with small freshwater shells, which they have the power of. fixing to the outside of their tubular cases, in order, probably, to give them weight and strength. The individual figured in the annexed cut, which belongs to a species very abundant in England, has covered its case w
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Bed of indusial limestone, interstratified with freshwater marl, near Clermont (Kleinschrod). We may often observe in our ponds the Phryganea (or Caddis-fly), in its caterpillar state, covered with small freshwater shells, which they have the power of. fixing to the outside of their tubular cases, in order, probably, to give them weight and strength. The individual figured in the annexed cut, which belongs to a species very abundant in England, has covered its case with shells of a small Planorbis. In the same manner a large species of caddis-worm which swarmed in the Eocene lakes of Auvergne was accustomed to attach to its dwelling the shells of a small spiral univalve of the genus Paludina. A Larva of recent Phryganea* lmndred of these minute shells are some- times seen arranged around one tube, part of the central cavity of which is often empty, the rest being filled up with thin concentric layers of travertin. The cases have been thrown together confusedly, and often lie, as in fig. 168, at right angles one to the other. When we consider Fis. 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
