. Elements of geology : a text-book for colleges and for the general reader. Geology. 162 ORGANIC AGENCIES. these seem to be living, or recently dead; some dead and empty, but still perfect; but most of them completely disintegrated. On account of the great abundance of the shells of one form of foraminifera, this. Fig. 129.—Shells of living Foraminifera: a, Orbvlina universa, in its perfect condition, showing the tubular spines which radiate from the surface of the shell; b, Globigerina bulloides, in its ordinary condition, the thin hollow spines which are attached to the shell when perfect h
. Elements of geology : a text-book for colleges and for the general reader. Geology. 162 ORGANIC AGENCIES. these seem to be living, or recently dead; some dead and empty, but still perfect; but most of them completely disintegrated. On account of the great abundance of the shells of one form of foraminifera, this. Fig. 129.—Shells of living Foraminifera: a, Orbvlina universa, in its perfect condition, showing the tubular spines which radiate from the surface of the shell; b, Globigerina bulloides, in its ordinary condition, the thin hollow spines which are attached to the shell when perfect having been broken off; c, Textularia variabilis ; d, Peneroplis planatus ; e, Rotalia concamerata ; f, Cristellaria subarcuatula. Fig. a is after Wyville Thomson; the others are after Williamson. All the figures are greatly enlarged (after Nicholson). soft, white mud is called globigerina ooze. Mingled in considerable numbers among the calcareous shells are others of silica. These are also partly animals (radiolaria) and partly plants (diatoms). The ex- traordinary resemblance of this deep-sea ooze, both in chemical and microscopic character, to chalk, leaves no room for doubt that chalk was formed in this 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 LeConte, Joseph, 1823-1901. New York : D. Appleton and Co.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1892
