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PALAEONTOLOGY. 



learn to adore with humility the goodness of their Divine 

 Author, who in the earth and in the heavens has shown to 

 inquiring man that his works are as infinite in extent as they 

 are all-perfect in structure. 



As every improvement in the construction of the telescope 

 has rewarded the astronomer with some new discovery in 

 the architecture of the heavens, so, in like manner, has every 

 addition to the power of the microscope introduced the natu- 

 ralist to new forms of existence in the organisms of the earth. 



Some families of Infusoria are enclosed in silicious 

 shields, marked with longitudinal, transverse, or oblique 

 lines, or adorned with various other forms of sculpture. 



Many genera of these loricated organisms belonging to 

 the families BACILLAKID.E and PEBIDINID^: have been found 

 in a fossil state in the tertiary deposits of Europe and Ame- 

 rica. The following table exhibits the principal genera :* 



BACILLARID^: 



PERIDINID.S: . 



The palseontological history of this class commences with 

 the discovery by Ehrenberg that the substance known as 

 Tripoli, polirschiefer of the Germans, was composed of the 

 silicious shields of many of the above genera. Subsequent 

 observations made by microscopists have shown that most 

 of the tertiary deposits in Europe and America contain a 

 vast accumulation of these microscopic fossils. 



Ehrenberg estimated that a cubic line of the polirschiefer 



* We have no doubt that many of these belong to the Desmidice and 

 Diatomacece. 



