forests present many evidences of subaërial conditions. Most
of the erect and prostrate trees had become hollow shells of
bark before they were finally embedded, and their wood had
broken into cubical pieces of mineral charcoal. Land-snails
and galley-worms _Xylobius_ crept into them, and they became
dens, or traps, for reptiles. Large quantities of mineral
charcoal occur on the surface of all the large beds of
coal. None of these appearances could have been produced by
subaqueous action. (6) Though the roots of the _Sigillaria_
bear more resemblance to the rhizomes of certain aquatic
plants; yet, structurally, they are absolutely identical with
the roots of Cycads, which the stems also resemble. Further,
the _Sigillariae_ grew on the same soils which supported
Conifers, _Lepidodendra, Cordaites_, and Ferns--plants which
could not have grown in water. Again, with the exception
perhaps of some _Pinnulariae_ and _Asterophyllites_, there
is a remarkable absence from the coal measures of any form of
properly aquatic vegetation. (7) The occurrence of marine, or
brackish-water animals, in the roofs of coal-beds, or even
in the coal itself, affords no evidence of subaqueous
accumulation, since the same thing occurs in the case of
modern submarine forests. For these and other reasons, some of
which are more fully stated in the papers already referred
to, while I admit that the areas of coal accumulation were
frequently submerged, I must maintain that the true coal is a
subaërial accumulation by vegetable growth on soils, wet and
swampy it is true, but not submerged."

I am almost disposed to doubt whether it is necessary to make the
concession of "wet and swampy;" otherwise, there is nothing that I