[Note IX.] [Page 50.] Minute Corals from Chalk.
Some layers of chalk are composed of an aggregation of many kinds of delicate corals, the interstices being filled up with Rotaliæ and other foraminiferous shells. In the cliffs near Dover there are several beds of this nature, well known to collectors for the profusion of exquisite specimens they yield to the experienced investigator. [Lign. 17, p. 50], represents several varieties from different localities; the small figures shew the natural size, and the enlarged ones their appearance when magnified. Attached to the surface of shells, and sometimes standing erect in crannies of flint nodules, beautiful corals may often be detected by the aid of a lens of moderate power. By brushing chalk in water, and examining the deposit, delicate fossils of this kind may also be obtained.[AR]
[AR] Refer to 'Medals of Creation,' p. 284, and to 'Wonders of Geology,' Lecture VI. p. 588, for a comprehensive view of Recent and Fossil Corals.
NATURE OF CORALS.
From the close analogy of the fossil corals to existing forms, it would not be difficult to give restored figures of the originals. Every little branch might be represented fraught with living polypes: in some cells the agile inmates might be shown with the mouth expanded, and the tentacula in rapid motion; in others withdrawn into their stony recesses, and devouring the infinitesimal atoms that constitute their food: even their varied hues might be introduced, and thus a vivid picture be presented of the microscopic beings which peopled the waters of the ancient chalk ocean.
That the Corals, which from their elegance and beauty are preserved in almost every cabinet, have been fabricated—or, in other words, built up—by polypes, in the same manner as the honey-comb of the bee and wasp, is so prevalent yet erroneous an opinion, that I am induced to point out its fallacy, by giving a brief account of the formation of these substances. The three recent specimens represented in [Lign. 27] will serve to illustrate my remarks.
Lign. 27:—Recent Corals.