226 Wisconsin Academy of Sciences, Arts, and Letters. 



Thus we see that we have divided the count j into three nat- 

 ural divisions. For the purposes of this paper we will consider 

 the region of maximum lead production as Grouj^ I. The inter- 

 mediate region as Group II, and the region which produces 

 practically no lead as Group III. The subjoined map shows 

 the divisions just described and gives also the location of the 

 lead mines — those jDortions of the map heavily shaded. It is 

 seen that there were a great many mines in Julien, Peru, Jef- 

 ferson and Center Townshi23S, a few in ]\Iosalem, Table Mound 

 and Concord, and only one or two of minor importance in our 

 great non lead producing area. 



Immigrants poured into this region early and it developed 

 fast. There were settlers here in 1833, and bv 1852 the to\\ai- 

 ship organization had been effected. It is unfortunate that no 

 well tabulated census report can be found for the period before 

 1852, for it was then that the region, especially in the lead area, 

 developed most rapidly. There were no mines being developed 

 elsewhere at this time to draw off the population as there were 

 after 1849 when gold was discovered in California, nor was 

 there any war such as the great Civil War to drain this country 

 of her busy workers. 



Table I. — Po2}ulation iier square onile. 



Compiled from Census of Iowa, 18S0 aud 1895. 



