The conifers are those trees which, as the name would imply, bear their fruit in the form of cones, such as the fir, larch, cedar, and others.  The order is one which is familiar to all, not only on account of the cones they bear, and their sheddings, which in the autumn strew the ground with a soft carpet of long needle-like leaves, but also because of the gum-like secretion of resin which is contained in their tissues.  Only a few species have been found in the coal-beds, and these, on examination under the microscope, have been discovered to be closely related to the araucarian division of pines, rather than to any of our common firs.  The living species of this tree is a native of Norfolk Island, in the Pacific, and here it attains a height of 200 feet, with a girth of 30 feet.  From the peculiar arrangement of the ducts in the elongated cellular tissue of the tree, as seen under the microscope, the fossil conifers, which exhibit this structure, have been placed in the same division.

The familiar fossil known to geologists as Sternbergia has now been shown to be the cast of the central pith of these conifers, amongst which may be mentioned cordaites, araucarites, and dadoxylon..  The central cores had become replaced with inorganic matter after the pith had shrunk and left the space empty.  This shrinkage of the pith is a process which takes place in many plants even when living, and instances will at once occur, in which the stems of various species of shrubs when broken open exhibit the remains of the shrunken pith, in the shape of thin discs across the interval cavity.

We might reasonably expect that where we find the remains of fossil coniferous trees, we should also meet with the cones or fruit which they bear.  And such is the case.  In some coal-districts fossil fruits, named cardiocarpum and trigonocarpum, have been found in great quantities, and these have now been decided by botanists to be the fruits of certain conifers, allied, not to those which bear hard cones, but to those which bear solitary fleshy fruits.  Sir Charles Lyell referred them to a Chinese genus of the yew tribe called salisburia.  Dawson states that they are very similar to both taxus and salisburia..  They are abundant in some coal-measures, and are contained, not only in the coal itself, but also in the sandstones and shales.  The under-clays appear to be devoid of them, and this is, of course, exactly what might have been expected, since the seeds would remain upon the soil until covered up by vegetable matter, but would never form part of the clay soil itself.