THE BASIN OF THE ATLANTIC. 257 



726. But in contemplating the leveling agencies that are at work 

 upon the solid portions of the crust of our planet, one is led, at 

 first thought, almost to the conclusion that the leveling agents, 

 however active they may be at the bottom of the atmosphere, are 

 comparatively powerless at the bottom of the sea. 



727. In the deep sea there are no abrading processes at work ; 

 neither frosts nor rains are felt there, and the force of gravitation 

 is so paralyzed down there that it can not use half its power, as 

 on the dry land, in tearing the overhanging rock from the precipice 

 and casting it down into the valley below. 



728. When considering the bottom of the ocean, we have, in 

 the imagination, been disposed to regard the waters of the sea as 

 a great cushion, placed between the air and the bed of the ocean 

 to protect and defend it from these abrading agencies of the atmos- 

 phere. 



729. The geological clock may, we thought, strike new periods; 

 its hands may point to era after era ; but, so long as the ocean 

 remains in its basin — so long as its bottom is covered with blue 

 water — so long must the deep furrows and strong contrasts in the 

 solid crust below stand out bold, ragged, and grand. Nothing can 

 fill up the hollows there ; no agent now at work, that we know 

 of, can descend into its depths, and level off the floors of the sea. 



730. But it now seems that we forgot these oceans of animal- 

 culfe, that make the surface of the sea sparkle and glow with life. 

 They are secreting from its surface solid matter for the very pur- 

 pose of filling up those cavities below. These little marine insects 

 are building their habitations at the surface, and when they die, 

 their remains, in vast multitudes, sink down and settle upon the 

 bottom. They are the atoms of which mountains are formed and 

 plains spread out. Our marl-beds, the clay in our river-bottoms, 

 large portions of many of the great basins of the earth, are com- 

 posed of the remains of just such little creatures as these, which 

 the ingenuity of Brooke and the industry of Berryman have en- 

 abled us to fish up from the depth of more than two miles (twelve 

 thousand feet) below the sea-level. 



731. TliQ^Q foraminifeixe, therefore, when living, may have been 

 preparing the ingredients for the fruitful soil of a land that some 



