Ceraunia and Omlria, supposed to be thunderbolts ; 'Ostra- 

 cites, resembling the oyster shell ; Spongites, having the form 

 of sponge ; Phycites, resembling sea-weed or rushes. He also 

 mentions stones resembling the teeth of hippopotamus ; and 

 says that Theophrastus speaks of fossil ivory, both black and 

 white, of bones born in the earth, and of stones bearing the 

 figure of bones. 



Tertullian (160 A. D.) mentions instances of the remains 

 of sea animals on the mountains, far from the sea, but uses 

 them as a proof of the general deluge recorded in Scripture. 



During the next thirteen or fourteen centuries, fossil remains 

 of animals and plants seemed to have attracted so little atten- 

 tion, that few references are made to them by the writers of 

 this period. During these ages of darkness, all departments of 

 knowledge suffered alike, and feeble repetitions of ideas de- 

 rived from the ancients seem to have been about the only 

 contributions of that period to Natural Science. 



Albert the Great (1205-1280 A. D.), the most learned man 

 of his time, mentions that a branch of a tree was found, on 

 which was a bird's nest containing birds, the whole being solid 

 stone. He accounted for this strange phenomenon by the vis 

 formativa of Aristotle, an occult force, which, according to the 

 prevalent notions of the time, was capable of forming most of 

 the extraordinary objects discovered in the earth. 



Alexander ah Alexandro, of Naples, states that he saw, in 

 the mountains of Calabria, a considerable distance from the 

 sea, a variegated hard marble, in which many sea shells but 

 little changed were heaped, forming one mass with the marble. 



With the beginning of the sixteenth century, a great impetus 

 was given to the investigation of organic fossils, especially in 

 Italy, where this study really began. The discovery of fossil 

 shells, which abound in this region, now attracted great atten- 

 tion, and a fierce discussion soon arose as to the true nature of 

 these and other remains. The ideas of Aristotle in regard to 



