Wisconsin and Missouri Lead Region. 

 Analysis of Pyrochlore, by Wohler. 



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Art. IY. — On the Wisconsin and Missouri Lead Region; by 

 James T. Hodge. 



The following observations upon some of the mineral resources 

 of Wisconsin and Missouri, were made in the course of a tour 

 through parts of the western country the last season. My at- 

 tention having been directed by the company by whom I was 

 employed, to ascertain the probable importance of a few mines 

 only, I was unable to devote much time to the elucidation of 

 the general geology of that country ; this I am happy to see 

 in the last number of the American Journal, is taken up by one 

 well able to connect its formations with those of our eastern 

 states. 



This region, according to Messrs. Owen and Locke, compre- 

 hends sixty two townships in Wisconsin, eight in Iowa, and ten 

 in Illinois, its extreme length from east to west being eighty seven 

 miles, and width from north to south fifty four miles. Though 

 the "cliff" limestone, the rock formation that contains the lead 

 ore, occupies a greater extent of country, it is in this portion 

 only that circumstances seem to have been favorable for the pro- 

 duction of fissures containing the ore. This rock is not broken 

 through by granite or other rock of igneous origin, as the lime- 

 stone of Missouri is, that there produces lead ore ; and its calca- 

 'reous character is more constant than this, which frequently 

 passes into a true siliceous rock. Its strata appear uniformly 



