448 



THE IKON RID G E 



SECTION VII. 



THE "IRON RIDGE" AND ORE-BEDS OF DODGE COUNTY, WISCONSIN. 



During the last three years, these deposits have attracted much notice, partly 

 on account of the interesting and anomalous character of the ore, and partly because 

 of the great practical value of a bed thus situated. The " Wisconsin Iron Company" 

 has the credit of making the first experiment upon this ore, and in fact, of erecting 

 the first, and at present the only stack furnace in Wisconsin, so far as my inquiries 

 extend. The same enterprising gentlemen, who were the pioneers in iron manu- 

 facture in the State of Indiana, where they erected the " Mishawaukie Furnace," 

 upon the bog ores near the Michigan line, have directed their skill, capital, and 

 energy to the same interest in the State of Wisconsin. Their works at Maysville, 

 in Dodge County, are driven by water, and consume the ore of the " Iron Ridge," 

 which is hauled on sleds, in winter, about four and a half miles. 



The geological position of this ore is not determined with precision. Mr. Lap- 

 ham, of Milwaukie, has traced the formations to the eastward of the boundaries of 

 Dr. Owen's survey of 1839, in places, as far as Lake Michigan ; but the fossils are so 

 few, and so much of the surface of the country mantled by deposits of drift, con- 

 cealing the rocks, and the limestones possessing lithological or external characters 

 so little marked, and so little diverse at distant points, and their stratification so 

 poorly defined, that it is very difficult to form a good opinion of the order of the 

 strata. 



There is great embarrassment in deciding upon the exact dip of such rocks, with- 

 out a protracted examination. According to Mr. Lapham, the lower sandstone 

 (F. 1) extends into Dodge County, at the northwest corner, and at the southwest 

 corner ; and the " Lower Magnesian Limestone," or F. 2, is seen through the 

 western part of the county, resting upon F. 1. 



In the southwest part of the county, along the range line, between Ranges thirteen 

 and fourteen east, the " Blue Limestone," or F. 3, A, is clearly developed. After pass- 

 ing an interval of four and five miles to the eastward of the latter formation, in 

 which the rocks are not visible, the " Upper Magnesian" or " Lead-bearing Lime- 

 stone" F. 3, b, is visible, having a breadth of about six miles ; the eastern observed 

 limit being six miles to the west of Rock River, on the south line of the county. 

 These rocks all dip easterly ; the amount and precise direction not yet determined, 

 nor yet the thickness of the separate formations. 



Passing now over to the lake-shore, near Milwaukie, Mr. Lapham finds the suc- 

 cession of rocks, taken in the reverse order, as follows : 



1. The " Corniferous Limestone" of New York and Michigan; corresponding to the "shell beds" of 

 the cliff limestone. 



'2. The " geodiferous" lime-rock of Eaton, and Niagara Limestone, of the New York Reports, supposed 

 to correspond with the lower part of the " Cliff Limestone" of Ohio, and F. 6 of Pennsylvania. 



