y 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.]

{107} See _Origin_, Ed. i. p. 312, vi. p. 453.

{108} See _Origin_, Ed. i. pp. 280, 281, vi. p. 414. The author
uses his experience of pigeons for examples for what he means by
_intermediate_; the instance of the horse and tapir also occurs.

{109} The absence of intermediate forms between living organisms
(and also as regards fossils) is discussed in the _Origin_, Ed. i.
pp. 279, 280, vi. p. 413. In the above discussion there is no
evidence that the author felt this difficulty so strongly as it is
expressed in the _Origin_, Ed. i. p. 299,--as perhaps "the most
obvious and gravest objection that can be urged against my theory."
But in a rough summary written on the back of the penultimate page
of the MS. he refers to the geological evidence:--"Evidence, as far
as it does go, is favourable, exceedingly incomplete,--greatest
difficulty on this theory. I am convinced not insuperable."
Buckland's remarks are given in the _Origin_, Ed. i. p. 329, vi. p.
471.

{110} That the evidence of geology, as far as it goes, is
favourable to the theory of descent is claimed in the _Origin_, Ed.
i. pp. 343-345, vi. pp. 490-492. For the reference to _net_ in the
following sentence, see Note 1, p. 48, {Note 161} of this Essay.

Referring only to marine animals, which are obviously most likely to be
preserved, they must live where <?> sediment (of a kind favourable for
preservation, not sand and pebble){111} 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 favourable, accords with facts of European
deposits{112}, but subsidence apt to destroy agents which produce
sediment{113}.

{111} 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, general