PERIPHERAL RANGES IX EUROPE 197 



tinction which ought to be kept constantly in view. Overthrusts and 

 local convexities of trend-lines may not accord with the direction of gen- 

 eral crustal creep in the same region, and surely it is of the first impor- 

 tance to determine correctly the larger of these facts — the direction of 

 the general crustal creep. This can be done safely only by the broadest 

 possible methods, such as have been used for Asia. Indeed, it is by an 

 extension of the reasoning for Asia to the European field that this ques- 

 tion can be most clearly and safely determined. 



In Asia the proof that the crustal sheet moved southward as a unit 

 does not rest alone on the existence and relations of the single frontal 

 fold-line, but upon the whole belt of subparallel Tertiary ranges, ex- 

 tending from the Philippines to Asia Minor. The belt as a whole is 

 peripheral in its nature; it is the crumpled margin of the crustal sheet. 

 The belt continues into Europe with about the same width and in the 

 same general relations — as a peripheral belt along the southern margin 

 of the continental sheet. 



Suess remarks that there is no natural line of demarkation between 

 Asia and Europe, and Penck happily describes Europe as "peninsular 

 Eurasia.'^* Suess points out the fact that the fold of the Caucasus ap- 

 pears to continue into Europe in the Eoumanian arc, the Carpathians, 

 and the Alps, while the Taurus fold continues in the Dinaric range of 

 Europe. In short, the Tertiary fold-belt extends right through from 

 Asia into Europe without any change, except that its simplicity in Asia 

 is replaced by complexity in Europe. The general relations are abso- 

 lutely identical. 



Broad facts like these are of a much higher order of value in determin- 

 ing the direction of general crustal creep than are facts relating to over- 

 thrusts and occasional exceptionally directed convexities of trend. The 

 peculiarities and exceptional features in Europe may be explained by 

 other causes, and can not be safely set up as proof of the direction of 

 general crustal movement. 



There are at least three causes for irregularity among the trend-lines 

 of the European ranges. The first and most important is the relative 

 smallness of the European crustal sheet, with consequent feebleness of 

 the thrust forces; second, the obstructing and complicating action of 

 block-like masses of the older European ranges, where included within 

 the belt of the Tertiary folds ; and, third, the tangential thrust from the 

 east, producing the Eoumanian, Alpine, and Betic arcs, as described by 

 Suess. 



* Science. February 26. 1909. p. 322. 



