RELATION TO JOINTS AND FAULTS 



145 



evidence of faulting is obtainable and where the absence of important 



planes of dislocation is to be assumed. Abnormally wide gaping of joints 



at regular intervals, as has been 



above described for Norwegian .- /' 



localities, may largely account for 



their regular space intervals. 



Among the many examples of 

 stream channels directed by joints 

 may be cited the ^^dells" of the 

 Wisconsin Eiver, near Kilbourn 

 City, Wisconsin ;^^ the Saranac 

 Eiver, in New York, and the 

 Abisko Canyon, in Swedish Lap- 

 land (see figure 21 and plate 13, 

 figure 1).2* 



On the other hand, within 

 many districts block faults are 

 known to be present, composing 

 a system which is in every way 

 similar as regards arrangement 

 and orientation to the oriented 

 drainage network; as, for exam- 

 ple, the Norwegian coast region 

 or the middle Ehine country. Of 

 Norway is is stated :^^ 



"The character of the surface near 

 the coast may be expressed by the 

 statement that it is broken up into 

 steps, so that one rises from the first 

 to the second and thence to the third 

 step, encountering each time the 

 same formation wherever the great step series 



\M ETEPS 



Figure 21. — Map of the Ahisko Canyon 

 northern Lapland 



in 



The canyon is directed along the line of rec- 

 tangular joints visible in the canyon walls. 

 (From the map by Otto Sjogren, with Indi- 

 cations of spacing added) 



is to be observed." 



Again :^^ 



•'In the little strip of Paleozoic formations between Langesund and the 

 Skiensthal we have before us, then, a section of country which is penetrated 

 through and through by faults upon already formed joint planes. We have 

 seen that the lines of the landscape are given by the principal joint systems. 



Transactions of the Wls- 



23 C. R. Van Hise : The origin of the dells of the Wisconsin, 

 consin Academy of Science, vol. 10, 1895, pp. 556-560. 



2* Otto Sjogren : Geografiska och Glacialgeologiska Studier vid Tornetrask. 

 Geologiska Undersokning, Arsbok 3, 1909, No. 2, pp. 34-45, figs, 15-16. 



*6 Kjerulf : Loc. cit., p. 329. 



2« BrOgger : Loc. cit., p. 400. 



Sverlges 



