GEOLOGY AND GEO-BOTANY OF ASIA. 73 



and the plains. It may thus be said that the high plateau of Asia has 

 its own fauna, so also its lower terrace, and also the lowlands of the 

 deserts and those of the prairies. 



* * * 



If the theory of Dana is approximately correct, then the gradual 

 growth of the Asiatic continent, as well as its present shape, can be 

 very well explained. During the Primary epoch, Asia consisted only 

 of the high plateau, which had the shape of a South America, directed 

 by its narrow point towards the Behring Strait. (Was not the North 

 Pole in that direction at that time?) On the line of division between 

 what was then the continent and the oceans which surrounded it at 

 that time, in consequence of the oblique thrust of which Dana speaks, 

 the border-ranges must have been formed all along the fringe of the 

 high plateaus, while a succession of parallel mountain ranges, result- 

 ing from as many foldings of the strata, were formed round the con- 

 tinent, just as the islands of Formosa, Japan, and so on, are now lifted 

 all round the continent of Asia in a series of curves indicated by Suess. 

 Later on, when the lower Mongolian terrace of the plateau emerged 

 in its turn from the ocean, the formation of mountains was continued 

 along its borders. It was then that, in all probability, the border- 

 ranges of the second terrace (Great Khingan, etc.) and the alpine 

 zone which fringes these border-ranges were formed. 



A similar formation is also found, but on a much smaller scale, 

 along the fringe of the third terrace — the terrace of the high plains; 

 but the arrest of upheavals was not sufficiently long at this stage, nor 

 was the difference of level between the high plains and the bottom of 

 the ocean sufficiently large to generate the high border-ranges such 

 as we find along the fringes of the plateau. And finally, during the 

 recent periods, a series of littoral chains has been lifted up, and is being 

 lifted up still, all along the present coasts of the Pacific Ocean. That 

 these chains are not generated in straight lines, but have a crescent 

 shape, as has been suggested by Suess, is pretty correct, and it must 

 also be remarked that the border-ranges of the plateau also are not 

 quite straight lines. We see, on the contrary, that straight lines are 

 intermingled with crescents, and when I speak of chains of mountains 

 having a direction from the southwest to the northeast, or from south- 

 east to northwest, I only mean that such is the general direction of 

 the chain, without pretending to say that the chain follows necessarily 

 a straight line. Sometimes the line is nearly straight, or it follows 

 a great circle of our globe ; this last case is very frequent, but sometimes 

 it also has the shape of a curve. It thus appears that the theory of 

 Dana, completed by the study of erosions which took place during an 

 extremely long succession of ages on a grand scale, and the generaliza- 

 tions concerning the orography of Asia, which are expounded here, 

 stand sufficiently in accordance for mutually confirming each other. 



