consolidated and rendered crystalline by metamorphism, and thus a great variety of silicated rocks may result, retaining little or no indication of any connection with the agency of life. We can scarcely yet conjecture the amount of light which these new facts may eventually throw on the serpentine and other rocks of the Eozoic age. In the meantime they open up a noble field to chemists and microscopists. [Footnote BB: The "red chalk" of Antrim, and that of Speeton, contain arenaceous Foraminifera and silicious casts of their shells, apparently different from typical glauconite, and the extremely fine ferruginous and argillaceous sediment of these chalks may well be decomposed glauconitic matter like that of the South Pacific. I have found these beds, the hard limestones of the French Neocomian, and the altered green-sands of the Alps, very instructive for comparison with the Laurentian limestones; and they well deserve study by all interested in such subjects.] When the marvellous results of recent deep-sea dredgings were first made known, and it was found that chalky foraminiferal earth is yet accumulating in the Atlantic, with sponges and sea urchins resembling in many respects those whose remains exist in the chalk, the fact was expressed by the statement that we still live in the chalk period. Thus stated the conclusion is scarcely correct. We do not live in the chalk period, but the conditions of the chalk period still exist in the deep sea. We may say more than this. To some extent the conditions of the Laurentian period still exist in the sea, except in so far as they have been removed by the action of the Foraminifera and other limestone builders. To those who can realize the enormous lapse of time involved in the geological history of the earth, this conveys an impression almost of eternity in the existence of this oldest of all the families of the animal kingdom.