14 IKFDSORIAL EARTHS. 



internal soft parts. But the most remarkable of tliese deposits of 

 diatomaceous remains, now in process of formation, is that which 

 Dr. W. J. Hooker has made known in the southern seas. Dr. 

 Hooker states that the waters of the Antarctic Ocean, between 

 the sixtieth and eightieth degrees of latitude, abound with Dia- 

 tornaceas to such a'degree that the sea, over large portions of this 

 wide area, is literally stained with them ; and that their shields 

 ai-e gradually producing a submarine deposit which flanks the 

 Victoria Earner, and covers a surface four hundred miles long by 

 one hundred and twenty miles broad ! This immense mass of 

 diatomaceous remains is in close proximity to Mount Erebus, an 

 active volcano, twelve thousand feet high ; and the circumstance 

 has suggested to Dr. Hooker whether there may not be some 

 direct communication between the ocean- waters and the internal 

 fires of the mountain, such as would account for the curious but 

 well-established fact, of the occurrence of the silicious shields 

 of the Diatomacece in the ashes and pumice of many active vol- 

 canoes. 



These immense submarine deposits of the shields of the 

 Diatomacea? may be said to be rocky strata now in the course of 

 formation. But similar deposits are found in many of the exist- 

 ing rock-formations of the earth's crust, and in some cases they 

 constitute by themselves beds of considerable thickness. The 

 so-called " infusorial earths " of various parts of the globe are 

 all of this description. One of the best known of these earths is 

 the famous berymehl, or mountain meal of Sweden, which, in 

 times of scarcity, the inhabitants are accustomed to mix with 

 their flour in making bread ! The Tripoli or rotten-stone, used 

 in polishing metals, the well-known Turkey-stone, and the 

 Polierschiefer, or polishing slate of Bilin, in Bohemia, are also 

 examples of fossilized remains of the Diatomacefe, the last-men- 

 tioned material occurring in a series of extensive beds averaging 

 fourteen feet in thickness. 



Again, the city of Richmond, in Virginia, is said to be built on 

 a bed of diatomaceous remains, eighteen feet in thickness and 

 of unknown extent ; while in 1839, Ehrenberg astonished the 

 inhabitants of Berlin with the discovery, that just beneath the 

 foundations of their houses there was an immense deposit of a 

 similar character ; excepting that, in this case, to add wonder to 

 wonder, a large proportion of the mass consisted of Diatomacea) 



