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We must mention, moreover, the great palæontological discoveries which, from the first foraminifera of the Cambrian formations up to the historical period of man, showed a great progressive scale in the appearance of the organisms and a very wide relationship between this scale and the natural systems of botany and zoölogy; and, finally, the principles of geology, which, under the leadership of Sir Charles Lyell, starting from the idea of an identity of the powers which were active in former times with those of the present, attempted to explain the most violent of the changes in the earth's crust in former times by causes active to-day.
The specimen was, indeed, pretty in more than a technical sense. Mingled with crystalline grains of quartz, glassy spicules, and water-worn fragments of coral, were a number of lovely little shells, some of the texture of fine porcelain, others like blown Venetian glass. "These are Foraminifera!" I exclaimed. "Yes." "Then it is not silver sand, after all?" "Certainly not." "But what is it, then?"
"Again, the were gradually becoming more and more convinced that all the important elements of the Globigerina ooze lived on the surface, and it seemed evident that, so long as the condition on the surface remained the same, no alteration of contour at the bottom could possibly prevent its accumulation; and the surface conditions in the Mid-Atlantic were very uniform, a moderate current of a very equal temperature passing continuously over elevations and depressions, and everywhere yielding to the tow-net the ooze-forming Foraminifera in the same proportion.
They would likewise be fatal, if the above Foraminifera, for instance, could be proved to have first come into existence during the Laurentian epoch, or the above Brachiopods during the Cambrian formation; for in this case, there would not have been time sufficient for the development of these organisms up to the standard which they had then reached.
Then on the foraminifera, which secretes a shell of lime from the water. Then on a step higher to the polycystina, which secretes a shell, or skeleton of flint-like material from the water. Then come the sponges. Then the coral-animals, anemones and jelly-fish. Then come the sea-lilies, star-fish, etc. Then the various families of worms. Then the crabs, spiders, centipedes, insects.
If the eozoon Canadense, found in the laurentian slate of the Cambrian formation in North America, is really an organism and not an inorganic form, the earliest vestiges of animal life we can find are the rhizopodes or foraminifera; and these organisms belong to the lowest stage of life to that stage which forms a kind of undeveloped intermediate member between the vegetable and animal kingdom, Häckel's kingdom of the protista.
The lower part of the calcaire grossier, which often contains much green earth, is characterised at Auvers, near Pontoise, to the north of Paris, and still more in the environs of Compiegne, by the abundance of nummulites, consisting chiefly of N. laevigata, N. scabra, and N. Lamarcki, which constitute a large proportion of some of the stony strata, though these same foraminifera are wanting in beds of similar age in the immediate environs of Paris.
I allude, first, to the salt marshes of our shores, their formation and uses, as well as their gradual disappearance under the advance of the sea; second, to the extended low islands in the form of reefs along the coast of the Southern States, the bases of which may be old coral reefs; third, the form of all our estuaries, which has resulted from the conflict of the sea with the drift formation, and is therefore, in a measure, a geological problem; fourth, the extensive deposits of foraminifera along the coast, which ought to be compared with the deposits of tripoli found in many tertiary formations; fifth, the general form and outline of our continent, with all its indentations, which are due to their geological structure.
The foraminifera which exemplify the lowest stage of animal existence exhibit, as we learn from the researches of Dr. Carpenter and of Messrs. Jones and Parker, extreme variability in their specific forms, and yet these same forms are persistent throughout vast periods of time, exceeding, in that respect, even the brachiopods before mentioned. Dr.
It seemed to me that the evidence was conclusive that the Foraminifera which formed the Globigerina ooze lived on the bottom, and that the occurrence of individuals on the surface was accidental and exceptional; but after going into the thing carefully, and considering the mass of evidence which has been accumulated by Mr.
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