TOPOGRAPHY. 



101 



are concerned, it would need little discussion here, even if the limits 

 of my field comprehended its entire extent and brought the whole 

 of the subject under consideration. But it deserves to be here record- 

 ed for the information and guidance of capitalists abroad, that for a 

 moderate expenditure this remarkable natural feature can be made to 

 yield an important avenue of transportation. 



In this connection the attention of capitalists is invited to the facts 

 given subsequently in relation to the water power of the Lower Fox 

 river, bearing in mind that grain bearing vessels will offer return 

 transportation at the most reasonable rates, thus placing manufactur- 

 ing establishments in the most advantageous relation to the thousands 

 of miles of rich territory along the Mississippi and its tributaries, and 

 the still other thousands of miles of shore line around the great lakes. 

 The enterprise for the improvement of this channel of communication, 

 under the auspices of the general government, is already (1876) far 

 advanced. 



It has been already remarked that the valley from Green Bay to 

 Lake Winnebago is exceedingly abrupt on the east, and very slightly 

 ascending on the west. The persistence of this peculiarity for so great 

 a distance points to some general cause. This is readily found in the 

 nature of the rock from which the valley was eroded. The strata in 

 this portion of the state dip to the eastward. Three groups of beds 

 are concerned in the formation of the valley. The uppermost one, 

 which forms the cliffs on the east side, consists of hard, thick-bedded 

 magnesian limestone, belonging to the Niagara period. Beneath this 

 lies a series of clays, soft shales, and limestones, very easily eroded by 

 water, forming the Cincinnati group, and below this again is a hard, 

 thick-bedded dolomite, known as Galena limestone, which forms the 

 bottom of the valley and its western slope, as shown in the accom- 

 panying figure : 



FIG. 1. 



1. Galena limestone. 2. Cincinnati shale. 3. Niagara limestone. 1 2. Gre^n Bay valley. 



It becomes evident enough then, from these facts and from an in- 

 spection of the valley, that it was formed by the wearing away of the 

 softer strata, leaving the harder ones above projecting in mural cliffs. 

 This eroding action is still going on, and to some extent is greatly fa,- 



