THE BASIN OF THE ATLANTIC. 265 



soft, consisting almost entirely of the remains of infusoria. The 

 Gulf Stream has literally strewed the bottom of the Atlantic with 

 these microscopic shells ; for the Coast Survey has caught up the 

 same infusoria in the Gulf of Mexico and at the bottom of the 

 Gulf Stream off the shores of the Carolinas, that Brooke's appara- 

 tus brought up from the bottom of the Atlantic off the Irish coast. 



760. The unabraded appearance of these shells, and the almost 

 total absence of the mixture of any detritus from the sea or foreign 

 matter, suggest most forcibly the idea of perfect repose at the bot- 

 tom of the deep sea. 



761. Some of the specimens that Brooke's apparatus has 

 brought up are as pure and as free from the sand of tlie sea as 

 the snow-flake that falls, when it is calm, upon the lea, is from the 

 dust of the earth. Indeed,' these soundings suggest the idea that 

 the sea, like the snow-cloud with its flakes in a calm, is always 

 letting fall upon its bed showers of these microscopic shells ; and 

 then we readily imagine that the " sunless wrecks," which strew 

 its bottom, are, in the process of ages, hid under this fleecy cov- 

 ering, presenting the rounded appearance which is seen over the 

 body of the traveler who has perished in the snow-storm. The 

 ocean, especially within and near the tropics, swarms with life. 

 The remains of its myriads of moving things are conveyed by 

 currents, and scattered and lodged in the course of time all over 

 its bottom. This process, continued for ages, has covered the 

 depths of the ocean as wdth a mantle, consisting of organisms as 

 delicate as the macled frost, and as light as the undrifted snow- 

 flake on the mountain. 



