46 GEOLOGICAL SURVEY OF WISCONSIN. 



These are especially valuable as showing the location of the public 

 roads, usually from actual survey. 



The specimens collected during the year, for study and comparison, 

 with the duplicates intended for the Academy of Sciences, University, 

 colleges, .and normal schools, now amount to. a very considerable 

 number, requiring much room and involving some expense for their 

 storage and proper arrangement for convenient reference in making 

 up the reports. 



Nearly five hundred townships (about one-third of the total area of 

 the state) have now been examined, with more or less minuteness, by 

 the several parties, as follows: 



By Prof. Irving in 1873, 45 townships. 



1874, - - 08 



By Prof. Chamberlin in 1873, 75 " 



1874, - - 130 " 



By Mr. Strong in 1873, - 50 " 



1874, - 66 " 



By Maj. Brooks in 1874, 17 " 



By Mr" Ives in 1874, - 7 " 



Several of the aneroid barometers purchased for the survey, having 

 been found to be imperfect and useless, others of better quality, which 

 have proved quite satisfactory, were obtained directly from the makers 

 in London, England. 



PROF. R. D. IKVING'S PARTY. Prof. Irving was directed to make 

 such explorations and surveys as would enable him to construct a geo 

 logical map and section along a line extending from the south part of 

 Dane county, northward, through portions of Columbia, Adams, and 

 Wood counties, to Grand Rapids, and thence up the Wisconsin rivei* 

 to Wausau; the breadth occupied to embrace two or three ranges of 

 townships; thence along the southern boundary of the Archaean rocks 

 in Wood, Clark, and Jackson counties, he was to extend his work 

 westward to the Black River Falls; the details of this important 

 locality having been previously examined by him. This route would 

 enable him to determine many important questions, in a portion of 

 the state heretofore but little known geologically ; especially in regard 

 to the quartzites, conglomerates, and other rocks of the Baraboo 

 river; the sandy region north of Portage; the kaolin beds; the 

 Mosinee hills; and the reported localities of iron ores. As the iron 

 ores of Lake Superior and the Menomonee region extend through 

 considerable distances, it was hoped that there might be a similar 



