4 7 O WILLI A M BERBER T HOBBS 



the small streams which enter the Wisconsin River at the 

 "Dells" as due to a system of joints induced by the gentle fold- 

 ing of the rocks. That a more or less uniform system of joints 

 exists in the rocks almost throughout the state of Wisconsin has 

 been shown by Buckley's observations.' 



So far as the writer is aware, the only detailed studies that 

 have been made establishing the definite relationship of the 

 stream channels of a region to its system of joints or faults, are 

 those of Brogger^ in the Langesund-Skien and Christiania 

 regions of southern Norway, and that of the writer ^ in the Pom- 

 peraug Valley region of Connecticut. Of the elaborately faulted 

 region which Brogger has studied, he states : 



It is not exaggerated when to my own astonishment I must state, as the 

 final result of my observations in this region, that almost every valley, every 



cleft, is formed along a fault fissure The significance of the faults for 



the formation of the valley straits is thus as profound as possible within the 

 stretch of land described, since almost every cliff, every vale, every bay 

 has been formed upon a line of dislocation ; indeed the presence of clefts 

 was for me, at the last, the surest index for the discovery of dislocations.* 

 [Translation.] 



Review of the geological structure of the Pomperaug Valley area 

 of Connecticut. — Regarding the Connecticut area to which refer- 

 ence is made, it will be necessary here to review the study in 

 order to make clear the generalizations with which this paper is 

 especially concerned. It is now well known that the several areas 

 of Newark rocks of the eastern United States are complexly 

 faulted, and the many common structural peculiarities of the 

 several isolated areas give rise to the belief that the forces which 

 have produced the dislocations have affected, not the Newark 

 rocks alone, but the larger region of which they are parts- — the 

 Piedmont plateau of the eastern United States. 5 



• Buckley : Bull. 4, Geol and Nat. Hist. Surv. Wis., pp. 450-460, 1898. 



'Brogger: Nyt Magazin for Naturvidenskaberne, Vol. XXVIII, pp. 253-419,. 

 1884. Ibid., Vol. XXX, pp. 99-231, 1886. 



3H0BBS: Twenty-first Ann. Rept. U. S. Geol. Surv., Pt. Ill, 1901, pp. 1-162. 



"Op. cit., pp. 34, 342. 



5Cf. Davis: The Triassic Formation of Connecticut, Seventh Ann. Rept. U. S. 

 Geol. Surv., 1888, pp. 481-490. 



