578 MANUAL OF NATUKAL HISTOEY. 



those extinct Pachyderms, the Hyotherium, Macra%~ 

 chenia, and Chalicotherium, and four species of Rhi- 

 noceros ; a solipede mammal, allied to the Horse, 

 from Eppelsheim, the Hippotherium ; and several 

 species of Trichechus or Walrus, from the middle 

 tertiary beds of France and England, may be alluded 

 to. The extinct genera of digitigrade Carnivora, 

 Machairodus, with its formidable canine teeth, and 

 Amyxodon, are also from these strata, besides nu- 

 merous genera of Rodents, as Trogontherium, Ste- 

 neofiber, Palceomys, Chalicomys, Archwomys, and 

 Chelodus. In the Falunian stage, Insessorial Birds 

 of the genera Gorvus and Fringilla, and the Gralla- 

 torial forms of Ciconia, 8colopax y and Phwnicop- 

 terus, have been identified. 



Loricated polygastric animalcules are found fossil 

 in the tertiary deposits of Europe and America, such 

 as the simple chain-like Bacillaria; the elegant bi- 

 valved Cocconeis ; the boat-shaped shields of Navi- 

 cula ; the discoid Gaillonella ; the slender, elon- 

 gated Synedra; the cruciform Podosphenia,. and 

 the toothed carapace of Uunotia, together with 

 Chcetotyphla and Peridinium. Many of these sili- 

 ceous shields are found in the substance termed 

 " Tripoli/' and in the " Bergmehl/' or fossil farina, 

 used as food, mixed with the ground bark of trees, 

 by the natives of Finland and Lapland. 



III. — Pliocene Group. 

 This group forms the most recent of the tertiary 

 formations, and is composed of beds of marl, marine 



