17. In this way upon your terrestrial body, several thousand tree, bush, plant and grass species have indeed perished, impressions of them having been found between layers of rock. Several primordial species of giant trees also have perished their wood now being found as hard coal. Likewise a large number of giant animals have completely vanished from existence as for instance the mammoth and a great many of yonder large winged amphibians still known as lizards.
18. Thus, even the gigantic bodies of some men have perished, who in primordial times were known by the term giants, together with several species of giant birds and also many fish not found among all the contemporary ones, except in some rare cases embedded within stones sometimes in well-preserved form.