ANNUAL REPORT FOR 1874. 



59 



TliG following table shows the amount of lead and zinc produced for 

 the years named : 



It will be seen from the above that while the production of lead ore 

 has been diminishing, during the past three or four years, that of zinc 

 ores is rapidly increasing. 



The explorations made north of the Wisconsin river, and outside of 

 the lead region proper, were necessarily of a more general chai-acter, 

 and the facts collected are represented upon maps on a much smaller 

 scale. Those made in 1874 were confined chiefly to a single range 

 (range two west) of townships, so that the entire extent of the 

 Paleozoic rocks could be explored within the time and means appli- 

 cable to this portion of the work. The most northern outlier of the 

 St. Peters sandstone was found in the south part of township twelve; 

 and the last occurrence of limestone (Lower Magnesian) in this range 

 is on sections 10 and 15 in township seventeen. 



Here are found those high, continuous dividing ridges forming seri- 

 ous obstacles to railroad construction, and from which fine views of 

 the surrounding valleys may be seen. 



The search for oil at " Oil City " resulted only in a fine flowing ar- 

 tesian well whose waters may be found to possess medicinal virtues, and 

 a knowledge of the strata below, down to the Archaean rocks. Here 

 the Potsdam sandstone has the unusual thickness of 814 feet. 



These explorations, being in a line nearly parallel with the Missis- 

 sippi river, will form a convenient base for the surveys to be made iu 

 1875, between that line and the river. 



