§61. RETROSPECT. 121 



elevating and depressing whole continents, — converting 

 the bed of the sea into dry land, — and submerging the dry 

 land into the abyss of the ocean. The volcano and the 

 earthquake are the effects of its local and paroxysmal 

 energies, — the quiet and insensible elevation and subsidence 

 of the land, of its slow but certain operation. By this 

 antagonist power the accumulation of the spoils of the 

 land, which the rivers, waves, and currents have carried 

 into the bed of the ocean, are again brought to the surface, 

 and form the elements of new islands and continents ; and 

 by the organic remains discovered in the strata, we trace 

 the nature of the countries whence these spoils were de- 

 rived. In the deltas and estuaries of modern times, — in 

 the detritus accumulating in the beds of the ocean, — in the 

 recent tracts of limestone forming on the sea-shores, — 

 beneath the cooled lava currents erupted from existing 

 volcanoes, — the remains of man and of his works, and of 

 the animals and plants which are his contemporaries, are 

 found imbedded. 



The dynamical effects of elevation appear to be referable 

 to three great divisions : — 1. The gradual rising of ridges 

 through large spaces of the earth's crust, and the conse- 

 quent production of longitudinal fissures and lines of vol- 

 canic vent ; 2. The long-continued protrusion and eruption 

 of igneous rocks along such lines of vent ; and 3. Local 

 eruptions and protrusions, producing valleys of elevation, 

 dislocations of the strata, and other phenomena that ter- 

 minate in ordinary volcanic action. 



Such are the deductions derived from the phenomena 

 which have been submitted to our examination. To the 

 mind previously unacquainted with the elements of geology, 

 I am ready to acknowledge that to attribute mutability to 

 the rocks and the mountains, must appear as startling and 

 incredible, as did the astronomical doctrines of Galileo to 

 the people of his times ; but the intelligent reader, who has 



