Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/357

 Rh and Coniferæ. Together with these, there occur other groups of Plants unknown in modern vegetation, and of which the duration seems to have been limited to the Epochs of the Transition Period. Among the largest and tallest of these unknown forms of Plants, we find colossal Trunks of many species, which M. Ad. Brongniart has designated by the name of Sigillaria. These are dispersed throughout the sandstones and shales that accompany the Coal, and can occasionally be detected in the Coal itself, to the substance of which they have largely contributed by their remains. They are sometimes seen in an erect position, where views of the strata are afforded by cliffs on the sea shore, or by inland sections of quarries, banks of rivers, &c.