394 R. M. BAGG FLUORSPAR IN THE ORDOVICIAN OF WISCONSIN 



He then states what is more significant with reference to our discovery : 



"No traces of this mineral have been observed in any of the unaltered rocks 

 of Silurian age farther west than New York, so far as can be ascertained." 

 "The lead region of Wisconsin, Iowa, and Illinois has failed to furnish a single 

 specimen." "Nor has a trace of fluor been observed in the great expanse of 

 territorj^ covered by the Niagara limestone in Illinois and Iowa." 



Twenty years later, when E. D. Irving^ published his check list of min- 

 erals found in Wisconsin, fluorite is mentioned as occurring in minute 

 purplish particles in the pink granite of Ashland County ; but he further 

 adds : ^^The complete absence of fluorite — which is so common an asso- 

 ciate of lead ores — from the lead ores of Wisconsin is worthy of note." 



Since both galena and fluorite are present in small amounts in the 

 strata of the l!\'eenah quarries, even though not abundant enough to be- 

 come of commercial value, the above statements no longer hold true, for 

 these dolomitic limestones are of the same horizon as those of the lead 

 region. 



Location of the Quarries and glacial Deposits therein 



The quarries described in this paper are situated in the southeast edge 

 of Neenah, beloAv the city park and about 1,000 feet west of Lake Winne- 

 bago. The upper surface of the limestone shows strong glacial planation 

 cut by striae trending north 25° east (magnetic), with some weaker stria- 

 tions crossing these, while on the southeast margin of the smaller quarry 

 some small cuplike depressions occur. The southwest border of the larger 

 quarry is covered by 7 feet of glacial drift, which is sharply divided into 

 two deposits. The lower formation is 4 feet thick and rapidly thins out 

 northward. It is overlain here by 3 feet of glacial till, resembling the 

 red clay so extensively developed along the Fox Kiver valley. There 

 are some rather large striated and faceted gabbro and granite boulders 

 scattered sparingly through this upper deposit, but beneath this is a 

 yellow gravel composed of small fragments of angular limestone with 

 but few of the larger igneous glaciated boulders present. 



The accompanying vertical section shows the relation of these glacial 

 deposits to the underlying Ordovician limestone. 



Mode of Occurrence of the Minerals 



The fluorite occurs in a definite layer of massive limestone about 5 feet 

 from the bottom of the main quarry. It consists of bright purple coat- 



Geology of Wisconsin, vol. i, 1882. Minerals of Wisconsin, pp. 309, 314. 



