STENO. 2 19 



must be to occupy the horizontal position ; and so 

 when we find them highly inclined, as in moun- 

 tains, for instance, we must refer this to subsequent 

 movement. He noticed that mountains are made 

 up both of horizontal and inclined strata, as may 

 be seen along their flanks. He infers that moun- 

 tains were once not in existence, and that they do 

 not grow, but that their regions are raised and 

 depressed and subject to rending and Assuring. 

 Steno clearly showed that the land had sunk and 

 had been again elevated in the geological ages, and 

 in considering the causes he seems to have grasped 

 the idea that the internal heat of the earth be- 

 coming less, the mass cools, and that the movements 

 on the surface have had to do with the cooling. 

 His most important work was removing fossils out 

 of the category of marvels, sports of nature, and as 

 things which grew in the earth, to the proper truth 

 that they are preserved parts of animals and plants 

 which were formerly alive. In 1688, Steno was 

 appointed to the chair of anatomy at Copenhagen ; 

 but he had to suffer from jealousy, and doubtless 

 some religious persecution influenced his desire to 

 leave his native country and to return to Florence 

 again. This he did, and Cosmo HI. entrusted him 

 with the education of his son. Steno then began 

 to give up science and to study theology, and wrote 

 several works on the subject by which he hoped to 

 convert his old natural history friends. One of 

 these involved him in a controversy with the 

 reformed clergy of Jena. The Pope, Innocent XL, 



