rSTUSOBT.4. 



221 



of "Bilin contained in round numbers 23,000,000 of indi- 

 viduals. As there are 1728 cubic lines in one cubic inch, 

 therefore a cubic inch of the Bilin polirschiefer would con- 

 tain 1728 X 23,000,000=39,744,000,000 fossil skeletons. 



A cubic inch of this fossiliferous rock weighed 220 grains, 

 so that each grain of Tripoli enclosed about 180,000,000 

 fossils ; the weight of each fossil, therefore, would be about 

 the T ^y millionth part of- one grain.* 



One of the most singular beds is that which has been 

 called fossil farina, or Bergmehl, by the natives of Finland 

 and Lapland, where it is found. This powder they mix with 

 flour, and consider nutritious. The microscope shows that 

 it is composed of the shields of Infusoria belonging to the 

 genera indicated in the table. 



These fossils are found likewise in opal and semi-opal, and 

 in the South of Europe the chalk-marls have yielded nume- 

 rous species. We have before us slides prepared with fossil 



FIG. 154. Magnified views of fossil infusorial remains. 



Infusoria from Bann, in Ireland (fig. 154), and Dolgelly, 

 N. Wales. We see their remains in thin slices of flint and 

 marble, and numerous species are obtained from the chalk 

 formation. So much have their remains contributed to the 

 rocks of this period, that it is possible that on every glazed 



* Taylor's Scientific Memoirs, vol. i. p. 407. 



