;n 



CHAP. IV. 



On the general Disposition of the Surface of the 

 Globe. 



To CONSIDER, in all its details, the subject which 

 forms the title of this Chapter, would he to trespass 

 on the province of Physical Geography. But this 

 department of Geographical science is in so many 

 points implicated with geology, that it is impossible 

 to avoid bestowing on it some consideration, although 

 it cannot here be allowed a large space. If it is the 

 business of the Geographer to trace the outlines of 

 coasts and islands, and the directions of chains of 

 mountains, it is that of the geologist to assign the 

 positions and courses of the strata by which these have 

 been modified or determined. Geology teaches the 

 Geographer the nature of the changes by which lakes 

 have been obliterated, by which rivers have changed 

 their courses ; it conducts him from the mountain to 

 the plain, and shows him why that which was once 

 sea is now firm land. In contemplating the rocks of 

 Niagara it foresees a period when that torrent shall no 

 longer plunge into the abyss below; and, in viewing 

 the fires of JEtna, it detects the causes that erected 

 the splendid colonnades of Staflfa and Sky. 



Of the Distribution of Sea and Land. 



The most prominent circumstance in the surface 

 of the earth relates to the general distribution of sea 

 and land; and if that which appears to be the next 



