THE BASIN OF THE ATLANTIC. 213 



which are at the bottom of the atmosphere, various agents are at 

 work, levehng both upward and downward. Heat and cold, rahi 

 and sunshine, the winds and the streams, all assisted by the forces 

 of gravitation, are unceasingly wasting away the high places on 

 the land, and as perpetually filling up the low. 



But in contemplating the leveling agencies that are at work 

 upon the solid portions of the crust of our planet which are at the 

 bottom of the sea, one is led, at first thought, almost to the con- 

 clusion that these leveling agents are powerless there. 



455. 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 preci- 

 pice and casting it down into the valley below. 



When considering the bottom of the ocean, we have, in the ini^ 

 agination, been disposed to regard the waters of the sea as a great 

 cushion, placed between the air and the bottom of the ocean to pro- 

 tect and defend it from these abrading agencies of the atmosphere. 



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 de- 

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



456. But it now seems that we forgot these oceans of animalcu- 

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

 They are secreting from its surface sohd 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 — 

 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 ena- 

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

 thousand feet) below the sea-level. 



These foraminiferce, therefore, when living, may have been pre- 



