886 STUDIES FOR STUDENTS 



4. The drainage system a network of parallel and iiitere sting 

 series. — The recognition of the fact that a system of joints and 

 faults has been responsible for the present directions of streams 

 within any region, aside from, purely theoretical considerations 

 of the closet naturalist, must be credited to Professor Theodor 

 Kjerulf, the former director of the Geological Survey of Norway. 

 His study of the newer and accurate topographic maps of the 

 country led him to see in the courses of the valleys, lakes and 

 fjords, the lines of dislocations. 1 The occurrence in many areas of 

 similarly regular networks of streams in which the elements are 

 essentially straight lines in parallel series over considerable 

 distances has now long been known, and has been given an 

 adequate explanation by Daubree as conditioned by the system 

 of fractures {lithoclases) of the region, in part by the faults 

 (paraelases) and in part by the joints (diaelases). 2 Daubree 

 cites the works of many geologists to show that such stream 

 networks have been observed in many widely separated areas. 

 Since the appearance of his work (1879), numerous other 

 examples have been added. 3 Lowl, in his work on valleys, 4 

 treats the subject under three heads — fold valleys, fault valleys, 

 and erosion valleys. He mentions the Rhine and the Leine in 

 Germany and the Piave in the southern Alps, as well as other 

 valleys, which are of the fault type. 



Daubree appears to ascribe the orientation of the larger num- 

 ber of stream channels to joints rather than faults, his view 



1 Kjerulf, Geologie des siidlichen und mittleren Norzvegens, auth. German ed. 

 by Ad. Gurlt (Bonn, 1880), pp. 328-34. See, however, in this connection, Stur, 

 "Das Isonzothal," etc., Jahrb. d. k. k. geol. Reichsanst., Vol. IX (1858), pp. 324-66, 

 and plate. 



2 Daubree, Geologie experimentale (1879), pp. 332-73. 



3 SUESS, Antlitz der Erde, Vol. I (1885), p. 339. Brogger, " Spaltenverwerfungen 

 in der Gegend Langesund-Skien," Nyt Magasin for Naturvidensk., Vol. XXVIII 

 (1884), pp. 253-419. " Ueber die Bildungsgeschichte des Kristianiafjords," ibid., 

 Vol. XXX (1886), pp. 99-231. Kemp, "Preliminary Report on the Geology of Essex 

 County," Report of State Geologist of Netv York for Year /8qj, Albany, 1894, pp. 

 438-40. Van Hise, "Origin of the Dells of the Wisconsin." Trans. Wis. Acad. Sci., 

 Vol. X (1895), 556-60. Hobbs, loc. cit. chap, v., also "The River System of Con- 

 necticut," Jour. Geol., Vol. IX (1901, pp. 469-85). 



4 Lowl, Thalbildung (Prag, 1884), pp. 19-43. 



