1S33.] 



Prof. Ehrenberg on Fossil Infusoria. 



157 



miiiions of animals, 18/ millions go to a grain, or the siliceous shield 

 of each animalcule weighs about the y-i-y millionth part of a grain. 



The animalcules of the Raseneisen are only -o Vo" ^^"^ diameter, 

 or the -^-Y part of the thickness of a human hair, i of the diameter of a 

 globule of the human blood, i of the blood globule of a frog. A cubic 

 line of such animal iron-ochre would thus, in the same relation, contain 

 one thousand millions, one cubic inch one billion, and one cube of nine 

 feet diameter one drillion, of living beings. If M^e suppose only one 

 fourth of this multitude to be really present, and take no notice of the 

 other three-fourths, there yet remain such enormous numbers as to 

 merit the greatest attention. 



Further Notices of Fossil Infusoria ; hy Prof. Ehrenberg, 



From Poggendorti's Annalen der Physik und Chemie, vol. xxxviii. 

 No. 6, p. 455, 1836. 



It has been announced as a well-ascertained fact, that the Polir- 

 schiefer of Bilin in Bohemia, which is a member of the tertiary forma- 

 tion, consists almost entirely of the siliceous shields of Gaiilonella 

 disians and other infusoria, without any foreign cement. The recent 

 Kieselguhr and the Bergmehl, from San Fiore, which are of less geolo- 

 gical interest indeed, consisting of larger infusoria shells, are better 

 adapted than the Polirschiefer (whose minute animalcules require a 

 high and clear magnifying power) to make these organic relations more 

 apparent and convincing. The kind exertions and reports of M. Alexander 

 von Humboldt, who lately visited the district of Bilin in his journey to 

 Teplitz, and sent me two very rich collections of the mineral pro- 

 ducts of that district, in various states, have furnished new materials 

 for the furtherance of my observations. 



Before I speak of this valuable addition to our subjects for investiga- 

 tion, I may mention, that an examination of the Polirschiefer of Planitz 

 (of which, by the friendly intervention of M. Weiss and the liberality 

 of M. Freiesleben in Freiberg, I have been enabled to examine a spe- 

 cimen whose locality was quite certain), has shown with certainty that 

 this layer also is a conglomeration of infusoria shells. The specimen 

 examined resembled the Saugschiefer of Bilin, and the infusoria shells 

 of the Gaiilonella distans are here filled with and connected by a silice- 

 ous cement, which somewhat mars the distinctness of their form ; I 

 have, however, seen some so plainly that I am convinced of the identity 



