Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/55

 Rh the refuge of some speculative philosophers to refer the origin of existing organizations, either to an eternal succession of the same species, or to the formation of more recent from more ancient species, by successive developments, without the interposition of direct and repeated acts of creation; and thus to deny the existence of any first term, in the infinite series of successions which this hypothesis assumes. Against this theory, no decisive evidence has been accessible, until the modern discoveries of geology had established two conclusions of the highest value in relation to this long disputed question: the first proving, that existing species have had a beginning; and this at a period comparatively recent in the physical history of our globe: the second showing that they were preceded by several other systems of animal and vegetable life, respecting each of which it may no less be proved, that there was a time when their existence had not commenced; and that to these more ancient systems also, the doctrine of eternal succession, both retrospective and prospective, is equally inapplicable.

Having this evidence both of the beginning and end of several systems of organic life, each affording internal proof of the repeated exercise of creative design, and wisdom, and power, we are at length conducted back to a period