CONTKOLLED EUROPEAN FRACTURE FIELDS 



161 



of the Silurian Basin is composed of two series whi(3h have the diagonal 

 directions, with numerous porphyry dikes which are aligned along the 

 meridian (see figure 32). ^^ 



Further south, on the 

 borders of Austria and 

 Italy, are the "Dolomites," 

 well known to tourists for 

 their remarkable scenery, 

 the mountains appearing in 

 squared towers, of which 

 "Die Drei Zinnen" form a 

 good example. As long ago 

 shown by Mojsisovics,®^ the 

 province is intersected by a 

 complex of faults.^* That in 

 addition a finely developed 

 joint system is present even 

 where no faulting is to be 

 observed, and that the indi- 

 vidual joints are grouped 

 into blocks of larger orders, 

 is brought out in many 

 photographs of the moun- 

 tains — as, for example, in figure 33. Here we find, moreover, that the 

 drainage system is definitely oriented on meridional and on diagonal 

 lineaments (see figure 34). Speaking of the larger area of the Alps 

 and the Tyrol, Salomon says :^^ 



"Wherever a hydrographic system is investigated in relation to its connec- 

 tion with the mountain structure, it will always be shown that if not lines of 

 displacement then, indeed, rock fissures are present which determine the direc- 

 tion of the running water." 



For districts in the southern Alps, Futterer has shown the predominance 

 of faults in the north-south, east-west, and northeast-southwest direc- 



r\«lotv\ eters 



Figure 34. — Drainage NetioorJc of the Dolomites 



Showing the dominance of meridional and diagonal 

 lineaments 



83 J. Krejcl und K. Feistmantel : Orographisch-geotektonlsche Ueberslcht des sllu- 

 rlschen Gebletes In Mlttleren Bohmen. Archiv f. d. naturw. Landesdurchf. v. BShmen, 

 vol. 5. No. 5, 1885. 



"3 Edmund Mo.isisovlcs von Mo.isvSr : Die Dolomit-Riffe von Sudtirol und Venetian. 

 Beltriige zur Bildungsgeschichte der Alpen. Vienna, 1879, pp. xiv and 552, many plates 

 and figures. 



0* Mojslsovlcs : Loc. cit., pp. 515-516. 



«' Wilhelm Salomon : Die Adamellogruppe, etc. Teil I, Abb. d. k. k. geol. Relchsanst., 

 vol. 21, 1908, pp. 1-26. 



