THE HISTORY OF DEVILS LAKE, WISCONSIN 349 



erosion in pre-Cambrian times nor would it preclude more than 

 one cycle. 



After the long series of events during the Paleozoic and subse- 

 quent history of the district, it does not seem possible to determine 

 which of the foregoing interpretations is correct. However, some 

 light is thrown upon the matter by consideration of the pre- 

 Cambrian history of Wisconsin, and the principles of stream adjust- 

 ment. It has been demonstrated by Weidman 1 and Martin 2 that 

 the surface of Wisconsin was degraded to a peneplain in pre- 

 Cambrian times, that this plain slopes south and is buried beneath 

 Cambrian sediments at an altitude of about 300 feet in the latitude 

 of Devils Lake, and that the quartzite ranges stood as erosion 

 remnants on this plain. Well-records in the Baraboo valley show 

 that the pre-Cambrian surface within the inclosure made by the 

 ranges is as low at least in some places as 340 feet A.T. A stream 

 must therefore have had entrance to the inclosure and a means 

 of escape from it. A broad, continuous, stream-made gap, filled 

 with Cambrian sediments, cuts through the North Range north- 

 west of Baraboo, and is probably the line of entrance or exit of a 

 large pre-Cambrian stream. The other gap, either entrance or 

 exit, is not known unless it be the Devils Lake gap. Neither the 

 Lower nor the Upper Narrows seems to be large enough and they 

 have not yet been proved to be pre-Cambrian in age. It is improb- 

 able that there is a buried gap, undiscovered, either in the North 

 or the South Range, which might have conducted the river in or 

 out of the area between the ranges. It is unlikely also that two 

 streams would adjust themselves as postulated in the second case 

 above. A stream working headward into a hard, high ridge with 

 a steep slope would hardly develop a course other than one more or 

 less nearly straight and nearly normal to the trend of the ridge. 

 But the stream flowing southeastward from Messenger's Creek 

 must have had a course which was distinctly curved, had supple- 

 mentary angles of 30 and 150 with the trend of the ridge, and 

 was oblique to the dip of the rocks. On the other hand, the 



1 Samuel Weidman, Bull. 16, Wis. Geol. and Nat. Hist. Surv., pp. 385-95, 592-600; 

 Jour. Geol., XI, 289-313. 



2 Lawrence Martin, Bull. 36, Wis. Geol. and Nat. Hist. Surv., pp. 347-73. 



