CHAPTER Y. 



FAUNA OF THE MOUNTAIN, 



THE animal life of the mountains of Pennsylvania is em- 

 braced within the division of temperate faunas of the globe, 

 or that portion of the surface of the planet included be- 

 tween the arctic and tropical parallels. The forms of this 

 fauna are not much diversified, and present a medium va- 

 riety between the region north of the tree limit or isothermal 

 zero, the line of perpetual ground-frost, and the tropical zone 

 of plants and animals. Extending from the vast desolate plains 

 surrendered to the tyranny of the frost-power to the region 

 of the sun's fires, with its arid extents of sand-deserts, this 

 temperate region presents an interesting series of animal 

 structures. A transition from the dreary monotony of one 

 belt to the brilliant diversity of the other, the temperate 

 regions are the theatre of life-manifestations, free from ex- 

 cessive contrasts, the intensation of the action of pure 

 physical forces, and the absolute despotism of the laws of 

 matter, as shown by the multitudinous, eccentric, and pecu- 

 liar forms of plant, bird, quadruped, fish, and reptile of the 

 equatorial regions, and the excessive but somewhat mono- 

 tonous animality of the maritime fauna of the arctic world. 

 The predominance of the plain and useful types of the 

 temperate region, as shown in the large, quiet mammals, 

 the ox, the bison, the deer, the horse, the hog, the tribes 

 that follow the bread cereals, must strike the most un- 

 observant when contrasted with the enormous reptiles, the 

 288 



