elf in entire accordance with Principal Dawson, who bases
his conclusions upon other, but no less forcible, considerations. In a
passage, which is the continuation of that already cited, he writes:--

"(3) The microscopical structure and chemical composition of the beds of
cannel coal and earthy bitumen, and of the more highly bituminous and
carbonaceous shale, show them to have been of the nature of the fine
vegetable mud which accumulates in the ponds and shallow lakes of modern
swamps. When such tine vegetable sediment is mixed, as is often the case,
with clay, it becomes similar to the bituminous limestone and calcareo-
bituminous shales of the coal-measures. (4) A few of the under-clays,
which support beds of coal, are of the nature of the vegetable mud above
referred to; but the greater part are argillo-arenaceous in composition,
with little vegetable matter, and bleached by the drainage from them of
water containing the products of vegetable decay. They are, in short,
loamy or clay soils, and must have been sufficiently above water to admit
of drainage. The absence of sulphurets, and the occurrence of carbonate
of iron in connection with them, prove that, when they existed as soils,
rain-water, and not sea-water, percolated them. (5) The coal and the
fossil forests present many evidences of subaerial 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 _Sigillarioe_ 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
_Pinnularioe_, 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