375 Stmclnre of ilie Earlh. 



dislincllv stratified, and contain an abundance of fossil Teuiaius of 

 vegetables, analogous to ferns, palms, and reeds; while those of 

 the transition class, contain almost exclusively the remains of ma- 

 rine animals. 



After these changes, another most remarkable revolution of the 

 globe took place, and another class was formed called the Upper 

 Secondary Rocks. The organic remains of the strata of this 

 class are chiefly those of marine animals, but of different genera 

 and species from those of the transition class. It is in the rocks 

 of this series that we first meet with remains of animals of a high- 

 er class, which possessed a brain and a back bone; they are all 

 of the oviparous order, such as the fish or hzard tribe. This up- 

 per series appears to have been formed not only under different 

 circumstances from the lower, but after a long interval, during 

 which the surface of the globe h:id been much fractured and dis- 

 placed; for the upper series do not lie regularly upon the other, 

 and parallel with them, but they cover the edges of the lower strata 

 in a confused manner. 



Tertiary* Strata comprise all the regular beds which have been 

 deposited subsequently to the chalk strata, on which they fre- 

 quently repose. It was formerly supposed that tertiary strata 

 were very limited in extent, and were confined to a few districts 

 in Europe; recent observations, however, prove that strata of 

 this class cover considerable })ortions of the surface in various 

 countries, though there are other countries in which they are en- 

 tirely wanting. Tertiary strata are the last formed or uppermost 

 of all the regular rock formations. They consist chiefly of clay, 

 limestone, and friable sandstone ; the lower series of these strata 

 contain numerous marine shells, while some of the middle and 

 upper strata contain shells resembling those found in our present 

 rivers, or in fresh-water lakes. The most remarkable fact respect- 

 ing the tertiary strata is, that some of them contain numerous 

 bones of quadrupeds of the class mammalia, but these for the most 

 part belong to genera and species which no longer exist upon the 

 earth. 



Volcanic and Basaltic] Rocks have been either ejected from 

 volcanoes, or poured out in a state of fusion from rents and open- 

 ings of the earth's surface. They cover in an irregular manner 

 the rocks of the preceding classes. In some situations the melted 

 mineral matter has taken a columnar form in cooling; in other 

 situations it fills vast fissures, called by miners, dikes. 



^ Derived from die Latin, tertius, third. 



t Derived from the French baiane, tawny, alluding to the color of 

 acme of the Ttrietipg. 



