Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/368

 364 in the structure of their wood, whereby the smallest fragment may be identified.

Recent microscopic examinations of fossil woods have led to the recognition of an internal structure, resembling that of existing Coniferæ, in the trunks of large trees, both in the Carboniferous series, and throughout the Secondary formations; and M. Ad. Brongniart has enumerated twenty species of fossil Coniferæ in strata of the Tertiary series. Many of these last approach more closely to existing Genera than those in the Secondary strata, and some are referable to them.

It has been further shown by Nicol, (Edin. New. Phil. Journal, January, 1834) that some of the most ancient fossil Coniferæ may be referred to the existing genus Pinus, and others to that of Araucaria; the latter of these comprehends some of the tallest among living trees, (See Pl. l, Fig. >br />The recognition of these peculiar characters in the structure of the stem, is especially important to the Geological Botanist, because the stems of plants are often the only parts which are found preserved in a fossil state.