the imbedding of organic
remains in deposits formed upon the land, I shall next consider the
including of the same in deposits formed under water.

It will be convenient to divide this branch of our subject into three
parts; considering, first, the various modes whereby the relics of
_terrestrial_ species may be buried in subaqueous formations; secondly,
the modes whereby animals and plants inhabiting _fresh water_ may be so
entombed; thirdly, how _marine_ species may become preserved in new
strata.

The phenomena above enumerated demand a fuller share of attention than
those previously examined, since the deposits which originate upon dry
land are insignificant in thickness, superficial extent, and durability,
when contrasted with those of subaqueous origin. At the same time, the
study of the latter is beset with greater difficulties; for we are here
concerned with the results of processes much farther removed from the
sphere of ordinary observation. There is, indeed, no circumstance which
so seriously impedes the acquisition of just views in our science as an
habitual disregard of the important fact, that the reproductive effects
of the principal agents of change are confined to another element--to
that larger portion of the globe, from which by our very organization we
are almost entirely excluded.[1059]

_Imbedding of Terrestrial Plants._

When a tree falls into a river from the undermining of the banks or from
being washed in by a torrent or flood, it floats on the surface, not
because the woody portion is specifically lighter than water, but
because it is full of pores containing air. When soaked for a
considerable time, the water makes its way into these pores, and the
wood becomes _waterlogged_ and sinks. The time required for this
process varies in different woods; but several kinds may be drifted to
great distances, sometimes across the ocean, before they lose their
buoyancy.

_Wood sunk to a great depth in the sea._--If wood be sunk to vast depths
in the sea, it may be impregnated with water suddenly. Captain Scoresby
informs us, in his Account of the Arctic Regions, that on one occasion a
whale, on being harpooned, ran out all the lines in the boat, which it
then dragged under water, to the depth of several thousand feet, the men
having just time to escape to a piece of ice. When the fish returned to
the surface "to blow," it was struck a second time, and soon afterwards
killed. The moment it expire