The beginnings of central Asia, as part of the Great continent, lie far back in the Tertiary period, during a time when mother Earth was in travail, giving birth to her last-born, the new order of continental and organic forms. In the throes of the contracting terrestrial crust there had been slowly born great mountain masses, ranges whose ice-capped giants now mark the boundary between north and south, extending half way round the earth, through the Pyrenees, Caucasus, and Himalayas to China.
The Eurasian continent was born, but in its infancy a great sea extended from the Atlantic through the Mediterranean to southeastern Asia. Later, during the middle Tertiary, this connection was broken, leaving a great interior sea called the Sarmatic, which once extended from Austria to beyond the Aral.
In the progressive development of land and climate, during Pliocene or late Tertiary time, this . . .