The geographical distribution of animals, with a study of the relations ...

200 ZOOLOGICAL GEOGRAPHY. [part in.mountainous, and much of their surface considerably elevated.Further east we have all European Turkey and Greece, amountain region with a comparatively small extent of levelplain. Id Asia the whole country, from Smyrna throughArmenia and Persia to the further borders of ,Affghanistan, is avast mountainous plateau, almost all above 2000, and extensivedistricts above 5000 feet in elevation. The only large tract oflow-land is the valley of the Euphrates. There is also somelow-land south of the Caucasus, and in Syria the valley of theJordan. In North Africa the valley of the Nile and the coastplains of Tripoli and Algiers are almost the only exceptions tothe more or less mountainous and plateau-like character of thecountry. Much of this extensive area is now bare and arid,and often even of a desert character ; a fact no doubt due, ingreat part, to the destruction of aboriginal forests. This lossis rendered permanent by the absence of irrigation, and, it isalso thought, by the abundance of camels and goats, animalswhich are exceedingly injurious to woody vegetation, and areable to keep down the natural growth of forests. Mr. Marshwhose valuable work Man and Nature gives much informationon this subject) believes that even large portions of the Africanand Asiatic deserts would become covered with woods, and theclimate thereby greatly improved, were they protected fromthese destructive domestic animals, which are probably notindigenous to the country. Spain, in proportion to its extent,is very barren ;Italy and European Turkey are more woody andluxuriant ; but it is perhaps in Asia Minor, on the range of theTaurus, along the shores of the Black Sea, and to the south ofthe Caucasus range, that this sub-region attains its maximum ofluxuriance in vegetation and in animal life. From the Caspianeastward extends a region of arid plains and barren deserts,diversified by a few more fertile valleys, in which the characteristicflora and fauna of this portion of the Palsearctic regionabounds. Further east we come to the forests of the HindooKoosh, which probably form the limit of the sub-region.Beyond these we enter on the Siberian sub-region to the north,and on the outlying portion of the Oriental region on the south.