Page:Popular Science Monthly Volume 19.djvu/249

Rh of the Protozoa and allied to Foraminifera. They represent it as an organism attaching itself by a gelatinous body to sea-floors, enveloping itself with a crust of carbonate of lime in which very small tubes penetrated to the surface through which the sarcodous material within projected in tapering fingers, to be withdrawn at the will of the animal; upon this another layer of protoplastic matter, formed in the growth of the creature, connected with the first, but separated throughout most of its extent by an interlamination of limestone, in which radiating canals are discerned, and which succeeds the earlier poriferous shell. Upon this new calcareous crusts arise, and thus a cellular and tuberiferous mound is formed, compacted and regular, along the base of attachment, but loose, granulated, and divergent at its summit.

In our present seas closely related organisms appear, the Rhizopods, minute bodies, structureless, mere pellets of protoplasm, yet possessed of a secretive function which incases them in exquisitely symmetrical houses of lime. They are naturally low in the animal scale, indeed primary, and the Eozoön seems to have been a Titan progenitor of these hosts of later protozoans whose numberless fragments form the chalk beds of England and France.

The Eozoön Canadense is found in the Laurentian rocks of Canada, other species in the Huronian of Bavaria, and specimens have been described from the Adirondacks and from Massachusetts. Forms strikingly resembling Eozoön may be found in the serpentine ledge in Fifty-ninth Street, near Tenth Avenue, New York. The soft parts in the calcareous skeleton of this Rhizopod have been replaced by minerals, and on the resemblance, amounting almost to identity, between the Eozoön and certain mineral pseudomorphs are based the objections made to its acceptance as of organic origin. King and Rowney, of Dublin, and Möbius, of Germany, have very vigorously attacked it, and lately Roemer rejects it from the list of palæozoic fossils. But it seems impossible to doubt the reality of its animal arrangement. Professor Hitchcock thoughtfully observes in this connection as regards its resemblance to mineral replacements, "Inasmuch as these structures represent the higher efforts of the mineral kingdom in crystallization and the nearest approach to the inorganic world allowed by animal forms, it is not strange that the two extremes should resemble each other sufficiently to deceive practical observers."

This was, in a few words, the archæan Continent. Its greatest area was in the north, with scattered islands and thin prolongations southward along the present axes of elevation. Subsequent periods built out from this and filled in the shadowy but prophetic sketch of North America—not an azoic or lifeless country, as once thought, yet a territory where silence reigned, broken only by the roar of the surf along its bleak margins, the whistle of the gale through its defiles, and the thunder of tempests upon its plains. "Lonely, silent, and impassive, heedless of man, season, or time, the weight of the Infinite seemed to brood over it."