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Farther preliminary Notices regarding Fossil Infusoria. By 

 Professor C. G. EHIIEKBERG. (Communicated to the 

 Royal Berlin Academy of Sciences.) * 



I HAVE already communicated the fact, that the polishing 

 slate (Polierschiefer) of Bilin in Bohemia, which is a member of 

 the tertiary formation, consists chiefly of the siliceous shields of 

 the Gaillonella distans^ and some other infusoria, without any fo- 

 reign cementing ingredient. The less interesting and newer 

 Kieselguhr, and the Bergrnehl of Santafiora, consisting of the 

 shells of larger infusory animals, are more suited than the po- 

 lishing slate to prove the existence of such fossil organic beings, 

 and to display them clearly ; for in the latter substance the ani- 

 mals are so minute as to render requisite the use of a powerful 

 and clear magnifying power. Humboldt having visited the 

 Bilin district, during a recent excursion to Teplitz, kindly pro- 

 cured for me two very rich collections of the local mineral pro- 

 ductions ; and has, by his exertions in procuring specimens, and 

 also by his communications, afforded me new materials for a 

 continuation of my investigations/)- 



Before mentioning the important results obtained from the 

 examination of these specimens, I must allude to observations I 

 have made on the polishing slate of Planitz, perfectly authentic 

 fragments of which were procured for me by Professor Weiss 

 from M. Freiesleben of Freiberg. I have now ascertained be- 

 yond a doubt, that the Planitz deposit is an accumulation of 

 the shells of infusory animals. The portion examined certain- 

 ly resembles the Saugschicfer of Bilin, and the shells of the 

 Gaillonella distans which it contains are so much mixed with a 

 siliceous cement, that the distinctness of their forms is somewhat 

 destroyed ; but I have seen some of them so clearly, that I am 

 perfectly convinced of the correctness of my assertion. There 

 is probably a more earthy form of this rock, resembling the po- 

 lishing slate, chiefly composed of the unaltered Gaillonella distans. 



* From Poggendorff's Annalen, vol. xxxviii. p. 455 1 836. 



f- According to Klaproth, the Kieselguhr of the Isle of France consists of 

 silica 72.0, water 21.0, alumina 2.5, and oxide of iron 2.5 ; and the Kieselguhr 

 or Bergrnehl of Santa Flora (in the district of Sienna), of silica JQ.O, water 12.0, 

 alumina 5.0, and oxide of iron 3.0. Saugschiefer, according to Bucholz, is 

 composed of silica 83.5, water 9.0, alumina 4.0. lime 0.5, oxide of iron 1.5. 



