. Elements of geology. Geology. Serpula attached to fossil Spatarurus ierm JOS, from i/ie chal our coast, is repre- sented with one-half of its shell stripped of the spines. In Fig. 9, a fossil of the same genus from the white Recent SpatangusTwith the chalk of England spines removed from one showS the liaked sur- 6.'s^1ne and tubercles, ^'^f ^hich the indi- natural size. viduals of this family a. The same magnified, exhibit when denuded of their bristles. The full-grown Serpula, therefore, which now adheres externally, could not have begun to grow till the Spa- tangus had died, and the spines
. Elements of geology. Geology. Serpula attached to fossil Spatarurus ierm JOS, from i/ie chal our coast, is repre- sented with one-half of its shell stripped of the spines. In Fig. 9, a fossil of the same genus from the white Recent SpatangusTwith the chalk of England spines removed from one showS the liaked sur- 6.'s^1ne and tubercles, ^'^f ^hich the indi- natural size. viduals of this family a. The same magnified, exhibit when denuded of their bristles. The full-grown Serpula, therefore, which now adheres externally, could not have begun to grow till the Spa- tangus had died, and the spines were detached. Now, the series of events here attested by a single fossil may be carried a step farther. Thus, for example, we oflen meet with a sea-urchin in the chalk, (see Fig. 11.), which has fixed to Fiff 11 lower valve of a crania, an extinct genus of bivalve mollusca. The upper valve (b Fig. 11.) is almost invariably wanting, though occa- sionally found in a perfect state of preservation in white chalk at some distance. In this case, we see clearly that the sea-urchin first lived from youth to age, then died and lost its spines which were carried away. Then the young °*chS^w"ththe"fo ^^^.nia adhered to the bared shell, and perish- vaive'of the crania turn ,* after which the upper valve was 6. uppe^vaive of the ^^P^^^^^^ ^^^^ lo^er before the Echinus Crania detached, became enveloped in chalky mud. It may be well to mention one more illustration of the manner. 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; Gibbes, Lewis Reeve, 1810-1894, former owner. DSI; Merrill, George P. (George Perkins), 1854-1929, former owner. DSI. Philadelphia : James Kay, Jun. and Brother ; Pittsburgh : C. H. Kay & Co.
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Keywords: ., bookauthorlyellcharlessir17, bookcentury1800, booksubjectgeology
