Page:Popular Science Monthly Volume 7.djvu/44

34 and other Foraminifera which are found in the deep-sea mud, live at the great depths in which their remains are found; and he supports this opinion by producing evidence that the soft parts of these organisms are preserved, and may be demonstrated by removing the calcareous matter with dilute acids. In 1857 the evidence for and against this conclusion appeared to me to be insufficient to warrant a positive conclusion one way or the other, and I expressed myself, in my report to the Admiralty on Captain Dayman's soundings, in the following terms:

"When we consider the immense area over which this deposit is spread, the depth at which its formation is going on, and its similarity to chalk, and still more to the marls of Caltanisetta, the question, 'Whence are these organisms derived?' becomes one of high scientific interest.

"Three answers have suggested themselves:

"In accordance with the prevalent view of the limitation of life to comparatively small depths, it is imagined either: 1. That these organisms have drifted into their present position from shallower waters; or 2. That they habitually live at the surface of the ocean, and only fall down into their present position.

"1. I conceive that the first supposition is negatived by the extremely marked zoological peculiarity of the deep-sea fauna.

"Had the Globigerinæ been drifted into their present position from shallow water, we should find a very large proportion of the characteristic inhabitants of shallow water mixed with them, and this would the more certainly be the case, as the large Globgerinæ so abundant in the deep-sea soundings, are, in proportion to their size, more massive and solid than almost any other Foraminifera. But the fact is, that the proportion of other Foramimfera is exceedingly small, nor have I found as yet, in the deep-sea deposits, any such matters as fragments of molluscous shells, of Echini etc., which abound in shallow waters, and are quite as likely to be drifted as the heavy Globigerinæ. Again, the relative proportions of young and fully-formed Globigerhice seem inconsistent with the notion that they have traveled far. And it seems difficult to imagine why, had the deposit been accumulated in this way, Coscinodisci should so almost entirely represent the Diatomaceæ.

"2. The second hypothesis is far more feasible, and is strongly supported by the fact that many Polycistineæ (Radiolaria) and Coscinodisci are well known to live at the surface of the ocean. Mr. Macdonald, Assistant Surgeon of H. M. S. Herald, now in the Southwestern Pacific, has lately sent home some very valuable observations on living forms of this kind, met with in the stomachs of oceanic mollusks, and therefore certainly inhabitants of the superficial layer of the ocean. But it is a singular circumstance that only one of the forms figured by Mr. Macdonald is at all like a Globigerina, and there are some peculiarities about even this which make me greatly doubt its affinity with that genus. The form, indeed, is not unlike that of a Globigerina, but it is provided with long radiating processes, of which I have never seen any trace in Globigerina. Did they exist, they might explain what otherwise is a great objection to this view, viz., how is it conceivable that the heavy Globgerina should maintain itself at the surface of the water?

"If the organic bodies in the deep-sea soundings have neither been drifted, nor have fallen from above, there remains but one alternative—they must have lived and died as they are.