400 



Article XX. 



Remarks on the real Occurrence of Fossil Infusoria, and their 

 extensive Diffusion; by Pro/. Ehrenberg. 



From J. C. PoggendorfF's Annalen der Physik und Chemie, vol. xxxviii. No. 5, 

 p. 213»; with a Plate. 



An the month of April of this year I communicated to the Academy f 

 a remarkable fact relative to the infusoria of the mineral springs of 

 Carlsbad, namely that they appeared to be the same species as those 

 met with on the French coasts of the Atlantic and in the Baltic. For 

 the knowledge of this fact I was indebted to the kindness of the pro- 

 prietor of the porcelain manufactory in Pirkenhammer, near Carls- 

 bad, M. Fischer, who, at my request, brought for me to Berlin some 

 of the water containing living animalcules. In order to follow up the 

 examination more closely and more extensively, I requested another 

 Bupply, which I received a fortnight ago in good condition. At the 

 same time M. Fischer informed me, in a letter dated 20th June, that 

 he himself had made a curious observation. He had remarked that the 

 Kieselguhr J (announced by M, Radig in the Jahrbucher fur Deutsch- 

 lands Heilquellen, &c., edited by MM. von Graefe and Dr. Kalisch, 

 1836, p. 193.), which occurs in the peat-bog of Franzensbad, near Eger 

 in Bohemia, consists almost entirely of the shields of Naviculae, and ap- 

 peal's to owe its origin to the action of volcanic heat on the bottom of 

 the sea. M. Fischer sent me, together with tliis information, a piece of 

 this fossil siliceous body, originally rather more than 2 inches long, 

 1 inch broad, and f inch high, which I have presented to the Royal 

 Mineralogical Cabinet ; he requested me at the same to determine 

 the forms of the animalculae, and to publish his observations together 

 with my results. Microscopical examination directly confirmed the 

 observation of M. Fischer, that the Kieselguhr of Franzensbad con- 

 sisted almost entirely of Naviculae ; and the great transparency and clear- 



• This paper was read in the Royal Academy of Sciences of Berlin on the 

 7th July, 1 83(5. [The translation is by Mr. W. Francis.] 



f Compare the Report of the Proceedings of the Royal Academy of Berlin, 

 1836, pp. 36, 50, and 55 ; and Wiegmann's Archiv. for Nat. Hist. 1836, p. 240. 



X [A kind of siliceous paste ; from Kiesel, silex, and Guhr, a term used in min* 

 ing for water carrying dissolved minerals when in a thick liquid state. — W. F.] 



