18 PALEONTOLOGY. 



organisms. Species of Bacillaria still exist which were in 

 being at the period of the deposition of the chalk. Existing 

 species of Diatomacecc have been detected as low down as the 

 oolite. The discovery by Ehrenberg of more than twenty 

 species of silicious-shelled Infusoria fossil, in the chalk and 

 chalk-marls, which are identical in species with some now 

 living in the bed of the Baltic, is an instructive addition to 

 the obscure history of the introduction of species of living- 

 things in this planet, and must add greatly to the interest of 

 the infusorial class in the eyes of the geologist and philosopher. 

 " For these organisms," writes Ehrenberg, " constitute a chain 

 which, though in the individual link it be microscopic, yet in 

 the mass is a mighty one, connecting the life phenomena of 

 distant ages of the earth, and proving that the dawn of the 

 organic nature co-existent with us reaches further back in 

 the history of the earth than had hitherto been suspected." 

 "The microscopic organisms are very inferior in individual 

 energy to lions and elephants, but in their united influences 

 they are far more important than all these animals."' 



If it be ever permitted to man to penetrate the mystery 

 which enshrouds the origin of organic force in the wide-spread 

 mud-beds of fresh and salt waters, it will be, most probably, 

 by experiment and observation on the atoms which manifest 

 the simplest conditions of life. 



ANIMALIA 



INVEETEBEATA. 



Bemains of invertebrate animals occur in strata of every 

 age, from the partially metamorphic and crystalline rocks of 

 the Cambrian system to the deposits formed by the floods of 

 last winter, and the tides of yesterday. They are found in 

 every country, from the highest latitude attained by Arctic 



