INFUSORIA AND OTHER ANIMALCULE. 253 



removed in one year, one-third of that entire mass 

 consisted of microscopic animals. The moors of 

 Limburg present accumulations of fossil Infusoria 

 twenty- eight feet in thickness. In the peaty layer 

 of Berlin, funnel-shaped deposits of Infusoria reach, 

 in some places, to the depth of sixty feet. There is 

 no doubt that they are still alive, and capable of 

 increase. Spontaneous motion may often be ob- 

 served in specimens taken from the greatest depth, 

 though less frequently than in those taken from the 

 surface. 



The antiquarian, in bringing the microscope to 

 bear in his researches, and by the discovery of 

 these siliceous shells of Infusoria in various ancient 

 articles of pottery, and the remains of similar 

 species in the clay of the vicinity in which they 

 occur, has proved that these vases were made 

 upon the spot, and not imported from the higher 

 civilized nations of that day, as had been previously 

 supposed. In like manner thieves have been tracked 

 and robberies discovered by means of the fossil 

 Infusoria adhering to the boots of the suspected 

 persons, though the latter had travelled many miles 

 from the spot where the act was committed. 



These fossil Infusoria and Diatomaceae are found 

 to belong both to marine and fresh- water species ; 

 many of them are in every respect identical with 

 species still living. Their geographical distribution, 



