Finch on the Tertiary Formations 31 



Art. II. — Geological Essay on the Tertiary Formations in 

 America, 6y John Finch, Fellow of the Philosophical 

 Society of Birmingham, Professor of Geology and Mine- 

 ralogy. 



[Read before the Academy of Natural Sciences, at Philadel^jhia. July 15;, 



1823,] 



Introduction. 



TO trace the connexion between the rocks of different 

 continents, to observe the order of their superposition, and to 

 examine the exterior formations of the earth, are the busi- 

 ness and study of the Geologist. 



The mountain masses, which occur in various parts of 

 the globe, obey one general law ; and the crystallized rocks 

 which contain no fossils, and are equally called primitive, 

 whether they occur in Europe, Asia, or America, are con- 

 stantly found in the same position. When we ascend in the 

 scale of formations, and arrive at those rocks which contain 

 fossils, we find each stratum decidedly marked by the re- 

 mains of zoophytes, or shells, peculiar to it. These fossils 

 constitute the medals of the ancient world, by which to as- 

 certain the various periods, during which the exterior coat 

 of the earth was consolidated. 



It has been observed, that these organized remains oc- 

 cur in so regular an order, that it is like examining a cabi- 

 net of shells, where you are sure to find, in every drawer, 

 those peculiar ones which have been deposited within it. 



The order of position among secondary rocks is also sel- 

 dom inverted. If in one quarter of the world you find a 

 sandstone, containing salt and gypsum, situated above anoth- 

 er, containing the impressions of peculiar madrepores, in all 

 other countries where these rocks are found, they preserve 

 the same relative position. 



This law is the foundation of Geology, on which alone it 

 rests ; and every portion of either the old or new continents 

 that is examined, seems to produce fresh evidence of its 

 truth. 



Among the discoveries made, in consequence of the ge- 

 nerous rivalry which takes place between nations in scien- 



