454 



DESCRIPTION OF 



THE 



COUNTRY BETWEEN 



I now proceed to give the facts I have gathered by observation and inquiry ujDon 

 this subject, taking the Blue Limestone of Cincinnati as the geological horizon for 

 comparison. Mr. Lapham has observed rocks of this age in the valley of Rock 

 River, a few miles north of Lake Koshkonong, in Range 13 east, Township 6 north, 

 Jefferson County, and again in Dodge County, in the same range in the east part of 

 Township 10 north, they crop out to the westward, occupying a belt of about a mile 

 in width, and consequently the thickness cannot be great. The same formation is 

 seen on the eastern shore of Green Bay, at Little Sturgeon Bay, Township 27 north, 

 Range 14 east, at the level of Lake Michigan. Between these points, about one 

 hundred and twenty miles apart, I am not aware that it has been traced, or even 

 seen, unless some of the Uuis7i-green beds of limestone, about Lake Winnebago, and 

 on Fox River, that I shall soon notice, are the equivalents of this formation. Dr. 

 Houghton examined and laid down the same rock on the west and north shore of 

 Green Bay, around the head of Little " Bay de Noquet" (pronounced Ba-de-nok), 

 in Michigan. 



The three points which I have noticed where this limestone makes its appear- 

 ance, are nearly in a right line, which bears about northeast by north. The surface 

 of the country on this line, from Jefferson County, rises to the east and northeast; 

 but to the left or westward of it, around Lake Winnebago, and in the valley of the 

 Fox River, there is a depression, along which the outcrop of the blue limestone may 

 well be expected, curving to the northwest of the direct line between the present 

 known points of outcrop. 



I have selected the Blue Limestone as a starting-point from which to reckon each 

 way up and down the series, because in Eastern Wisconsin it is the bed about 

 which all geologists will best agree as to its position. 



To show more forcibly the difficulties that exist in the present state of our exa- 

 minations, in arranging these rocks, I will give the results of examinations made in 

 the Silurian strata, both on the east, in Michigan and in Canada, and on the west, in 

 Wisconsin. It should likewise be remembered, that neither the Michigan nor the 

 Eastern Wisconsin surveys are complete or fully reported upon, and therefore the 

 lights that are derived collaterally from these sources are not only not full, but 

 subject to future modifications. 



The New York system of rocks has now been traced from Virginia through 

 Pennsylvania, and through New York, Canada, Michigan, Wisconsin, and Minnesota, 

 leaving its vast area indeterminate on the west and northwest. We are therefore 

 considering a portion midway between its extremes. A comparison of sections 

 showing the order and nature of these beds, at different points, both east and west, 

 and also of the region under consideration, may be useful and interesting. 



A glance at the tabular arrangement, on the next page, of the rocks, as different 

 observers have reported them, shows that although other beds change or disappear, 

 the equivalent Blue Limestone of Cincinnati runs from the eastern part of Michigan 

 to the western part of Wisconsin. Doubtless there are some imperfections in the 

 grouping of the various formations by different authors, but a striking uniformity 

 pervades the sections when we regard the broad space which they represent. 



