The foundations of The origin of species : a sketch written in 1842 / edited by Francis Darwin.
- Charles Darwin
- Date:
- 1909
Licence: Public Domain Mark
Credit: The foundations of The origin of species : a sketch written in 1842 / edited by Francis Darwin. Source: Wellcome Collection.
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![infer, each separate formation presents even an approach to a consecutive history, my theory must be given up. Even if it were consecutive, it would only collect series of one district in our present state of knowledge; but what probability is there that any one formation during the immense period which has elapsed during each period will generally present a consecutive history. [Compare number living at one period to fossils preserved—look at enormous periods of time.] Referring only to marine animals, which are obviously most likely to be preserved, they must live where (?) sediment (of a kind favourable for pre¬ servation, not sand and pebble)1 is depositing quickly and over large area and must be thickly capped, (illegible) littoral deposits: for otherwise denudation (will destroy them),—they must live in a shallow space which sediment will tend to fill up,—as movement is (in?) progress if soon brought (?) up (?) subject to denudation,—[if] as during subsidence favour¬ able, accords with facts of European deposits2, but subsidence apt to destroy agents which produce sediment3. I believe safely inferred (that) groups of marine (?) fossils only preserved for future ages where sediment goes on long (and) continuous(ly) and with rapid but not too rapid deposition in (an) area of subsidence. In how few places in any one region like Europe will (?) these contingencies be going on ? Hence (?) in 1 See Origin, Ed. i. p. 288, vi. p. 422. “ The remains that do become embedded, if in sand and gravel, will, when the beds are upraised, generally be dissolved by the percolation of rain-water.” 2 The position of the following is not clear:—“ Think of immense differences in nature of European deposits,—without interposing new causes,—think of time required by present slow changes, to cause, on very same area, such diverse deposits, iron-sand, chalk, sand, coral, clay ! ” 3 The paragraph which ends here is difficult to interpret. In spite of obscurity it is easy to recognize the general resemblance to the discussion on the importance of subsidence given in the Origin, Ed. i. pp. 290 et seq., vi. pp. 422 et seq.](https://iiif.wellcomecollection.org/image/b31351761_0059.jp2/full/800%2C/0/default.jpg)
