14 HISTORY OF GEOLOGY AND PALAEONTOLOGY. 



of nature, or as mineral forms, or if they really were the 

 remains of animals and plants that had once lived, and had 

 been brought by the Flood or some other catastrophe into their 

 present position. 



The world-famed artist and architect, Leonardo da Vinci 

 (1452-1519), took part in the discussion. He had in his youth 

 been engaged as an engineer in the construction of canals in 

 North Italy, and had then seen numerous fossils in position 

 in the rocks. The opinions he formed regarding them are 

 remarkable for their clearness and correctness. Leonardo said 

 that the marine organisms scattered in the earth in the form of 

 fossils had actually lived where we now find them. The sea at 

 that time covered the mountains of North Italy: the river-mud 

 brought to the sea from Alpine lands filled the shells of dead 

 mussels or snails, and accumulated on the sea-floor; afterwards 

 the mud deposits became dry land, and the fossils found in 

 them were the casts of the ancient cells. He ridiculed, as 

 absurd and unscientific, the idea that such perfect models of 

 living organisms could have taken origin in the rocks under 

 hypothetical creative influences of the stars. 



The Neapolitan, Alessandro degli Alessandri (1461-1523), 

 mentions petrified conchylia in the Calabrian mountains, and 

 ascribes their presence to an inundation of the continent by 

 the ocean, caused by some exceptional catastrophe, or by a 

 change in the axis of rotation of the earth. 



Fracastoro, 1 in the year 1517, gave clear expression to his 

 convictions about fossils, which were in accordance with those 

 of Leonardo da Vinci. During the building of the citadel of 

 San Felice in Verona, the workers found fossil mussels in the 

 rocks and laid them before Fracastoro, begging him to explain 

 the marvel. Fracastoro repudiated the doctrine of a vis plastica 

 in the earth as impossible; and just as little did he give 

 credence to the view that explained fossils as creatures left by 

 the great Flood. The Flood, he said, was of short duration, 

 and in the nature of things it would have left not marine but 

 fresh-water mussels behind; further, on the assumption that 

 the mussels had been carried from the ocean to the land by the 

 Flood, their remains would have been scattered over the 



1 Hieronymus Fracastoro, born at Verona in 1483, studied at Padua, 

 and became Professor of Philosophy there in 1502; afterwards practised 

 medicine as a physician in Verona, and in his capacity of physician to Pope 

 Paul III. was a member of the Council of Trent. He died in 1553. 



