48 PRIMARY STRATIFIED ROCKS. 



ble planet, through long successions of change and of con- 

 vulsive movements, to a tranquil state of equilibrium ; in 

 which it has become the convenient and delightful habita- 

 tion of man, and of the multitudes of terrestrial creatures that 

 are his fellow tenants of its actual surface.* 



CHAPTER VJ. 



Primary Stratified Rocks. 



In the summary we have given of the leading phenomena 

 of unstratified and volcanic rocks, we have unavoidably 

 been led into theoretical speculations, and have seen that 

 the most probable explanation of these phenomena is found 

 in the hypothesis of the original fluidity of the entire mate- 

 rials of the earth, caused by the presence of intense heat. 

 From this fluid mass of metals, and metalloid bases of the 

 earths, and alkalies, the first granitic crust appears to have 

 been formed, by oxidation of these bases ; and subsequently 

 broken into fragments, disposed at unequal levels above and 

 below the surface of the first formed seas. 



Wherever solid matter rose above the water, it became 

 exposed to destruction by atmospheric agents ; by rains, 

 torrents, and inundations ; at that time probably acting with 

 intense violence, and washing down and spreading forth, in 

 the form of mud and sand and gravel, upon the bottom of the 

 then existing seas, the materials of primary stratified rocks, 

 which by subsequent exposure to various degrees of sub- 

 terranean heat, became converted into beds of gneiss, and 

 mica slate, and hornblende slate, and clay slate. In the 



* See farther details respcctinff the effects of volcanic forces in the 

 description of PI. I. Vol. ii. 



