GOATS. 



235 



of such tiers and shrubs as they can reach, whereas sheep mainly confine them- 

 selves to grazing. On account of these browsing habits goats are extremely 

 destructive to forests, eating off the tops of the young trees and thus preventing 

 all new growth. 



Geologically, goats appear to be somewhat older than the sheep, remains of 

 certain species having been obtained from the Pliocene rocks of the Siwalik Hills 

 in Northern India, while those of others occur in the superficial deposits of the 

 plains of Central Europe. The latter belong to a species, of ibex, which is a matter 

 of some interest as showing that during a colder epoch these animals could exist 



SKELETON OP THE IBEX. 



in the lowlands, from whence, with an increase of the temperature, they migrated 

 to the various mountain-chains, where they have differentiated into distinct species 

 from isolation. This explains the occurrence of allied species of wild goats in the 

 Caucasus and the Pyrenees, and in the Alps and the Sinaitic Peninsula. 



The Caucasian Wild Goats, or Tur {Capra cylindricornis, etc.). 



There occur in the Caucasus range three different kinds of wild goats, locally 

 known as tur, which, as being those approaching most nearly to the sheep, 

 naturally come first. These three kinds are commonly ranked as distinct species, 

 but it may be a question whether they are not really only races of one species 



