PALEONTOLOGICAL DISCOVERY. 221 



ferred therefrom that the sea had once covered that whole region. 

 Empedocles, of Agrigentum (450 b. c), believed that the many hip- 

 popotamus-bones found in Sicily were remains of human giants, in 

 comparison with which the present race were as children. Here, he 

 thought, was a battle-iield between the gods and the Titans, and the 

 bones belonged to the slain. Pythagoras (582 b. c.) had already an- 

 ticipated one conclusion of modern geology, if the following statement, 

 attributed to him by Ovid, was his own : * 



" Vidi ego quod fuerat solidissima tellus, 

 Esse fretum : vidi factas ex sequore terras ; 

 Et procul a pelago conchoB jacuere marina3." 



Aristotle (384-322 b. c.) was not only aware of the existence of 

 fossils in the rocks, but has also placed on record sagacious views as to 

 the changes in the earth's surface necessary to account for them. In 

 the second book of his " Meteorics," he says : " The changes of the 

 earth are so slow in comparison to the duration of our lives, that they 

 are overlooked ; and the migrations of people after great catastrophes 

 and their removal to other regions, cause the event to be forgotten." 

 Again, in the same work, he says : " As time never fails, and the uni- 

 verse is eternal, neither the Tanais nor the Nile can have flowed for 

 ever. The places where they rise were once dry, and there is a limit 

 to their operations : but there is none to time. So of all other rivers ; 

 they spring up, and they perish ; and the sea also continually deserts 

 some lands and invades others. The same tracts, therefore, of the 

 earth are not, some always sea, and others always continents, but 

 everything changes in the course of time." 



Aristotle's views on the subject of spontaneous generation were less 

 sound, and his doctrines on this subject exerted a powerful influence 

 for the succeeding twenty centuries. In the long discussion that fol- 

 lowed concerning the nature of fossil remains, Aristotle's views were 

 paramount. He believed that animals could originate from moist 

 earth or the slime of rivers, and this seemed to the people of that 

 period a much simpler way of accounting for the remains of animals 

 in the rocks than the marvelous changes of sea and land otherwise re- 

 quired to explain their presence. Aristotle's opinion was in accordance 

 with the Biblical account of the creation of man out of the dust of the 

 earth, and hence more readily obtained credence. 



Theophrastus, a pupil of Aristotle, alludes to fossil fishes found 

 near Heraclea, in Pontus, and in Paphlagonia, and says, " They were 

 either developed from fish-spawn left behind in the earth, or gone 

 astray from rivers or the sea into cavities of the earth, where they had 

 become petrified." In treating of fossil ivory and bones, the same 

 writer supposed them to be produced by a certain plastic virtue latent 



* " Metamorphoses," liber xv., 262. 



