158 W. H. HOBBS REPEATING PATTERNS IN STRUCTURE OF LAND 



be that when we have advance^ farther in our studies of fracture fields 

 the more difficult fracture complexes may be deciphered, but for the 

 present it is necessary to confine our attention to those within which 

 some sort of orderly arrangement can be made out. The significant fact 

 is that wherever a relatively simple and orderly system has been discov- 

 ered, the dominant structural and relief directions represent one or more 

 of the elements within the quadruple set which has been above described. 



EUROPEAN FRACTURE FIELDS WHICH EXHIBIIT CONTROL 



As in North America, so also in Europe, the existence of districts of 

 complex fracture structures has quite generally withdrawn the attention 



of geologists from the many districts which, 

 as regards both their structural and their 

 relief characteristics, are relatively simple. 

 The writer has now for a number of years 

 collected and compared the observations 

 made in such districts, with the result of 

 showing that the same quadruple set of 

 dominant lineaments is common to Eu- 

 u i-z\j I ,y,\ r U/L' — ^ I'ops and North America alike. The data 

 / ) /r J 1 17 X \ on which this conclusion has been based 



must be more fully presented in another 

 place, but mention of a few districts will 

 suggest the nature of the evidence assem- 

 bled. That the above described quadruple 

 FiGuuK ^1.— Oriented Drainage sct applies for Norway is clear from the 

 Network of the Vicinity of gtudics made by Kierulf more than a 



Charny, in France 



(After Daubree) 



quarter of a century ago (see figure 7, page 

 132).^® In southern Norway, Brogger's 

 more detailed studies have shown the predominant influence of two of 

 the four fracture series in the system — the meridional and trans-merid- 

 ional — with the northeast to southwest series playing in addition a subor- 

 dinate role :^^ 



"The dislocations — they are here movements along joints — have in fact cut 

 the land through and through, and not alone in one system of lines, but, first, 

 chiefly in two principal directions and then further on other less prominent 

 directions. . . . 



^* Kjerulf : Loc. cit. 



^'^ W. C. Br5gger : Spaltenverwerfungen in der Gegend Langesund-Sklen, Nyt Magazln 

 for Naturvidernskaberne, vol. 28, 1884, pp. 384-401-402. 



