Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/210

 It must be obvious that another and most important branch of natural history is enlisted in aid of Geology, as soon as the study of the character of fossil Fishes has been established on any footing, which admits of such general application as the system now proposed. We introduce an additional element into geological calculations; we bring an engine of great power, hitherto unapplied, to bear on the field of our inquiry, and seem almost to add a new sense to our powers of geological perception. The general result is, that fossil Fishes approximate nearest to existing genera and species, in the most recent Tertiary deposites; and differ from them most widely in strata whose antiquity is the highest; and that strata of intermediate age are marked by intermediate changes of ichthyological condition.