 Buffon subsequently made some steps toward combining the thesis of the historical degeneration of species with his theory of historical cosmology in Les (subsequently Des) Époques de la Nature, first published as a supplement to the Natural History in 1778. In this treatise he reworked his earlier speculations on the “theory of the earth”, first set out in 1749, adding to this a historical chronology of the age of the earth determined experimentally in the 1770s by quantitative studies on cooling spheres of metal. In this imaginative synthesis, and drawing on an allegorical reading of Genesis 1, Buffon combined a history of the Earth with a historical sequence of the emergence of living forms (Buffon 1779). In doing so he expanded the time scale of earth history considerably beyond the accepted “Mosaic” chronology of less than 10,000 years from the beginning of the world to the present, to an estimate of approximately 75,000 years in the published version, and over two million years in his draft manuscript. In this treatise Buffon offered a naturalistic solution to the two inherited Cartesian dilemmas. First, his schema was offered as a realistic account. The Cartesian language of counterfactualism has disappeared. Second, he integrated the history of living forms into this comprehensive history of the world. Further naturalizing his theory of the internal molds and organic molecules, both were now seen to arise by natural laws from the natural attraction of different shapes of matter and from the changes in matter as the earth cooled from its origin in matter cast off by the sun. Animals first originated by the spontaneous clumping together of these organic molecules on the cooling earth (Buffon 1779: Fifth Epoch).