308 GEOLOGY OF EASTERN WISCONSIN. 



ductive of lead arid zinc in the southwestern part of the state, there 

 is little reason to expect that it will prove so in the region under con- 

 sideration, for, although the ores of those metals occur not unfre- 

 quently in small quantities, no indications of valuable deposits have 

 yet been developed. 



Analysis shows that much of this formation from Dodge county 

 southward is a comparatively pure magnesian limestone, and is well 

 adapted to the manufacture of quicklime. It is used for this pur- 

 pose at Watertown, Ft. Atkinson, Whitewater and elsewhere. It is 

 estimated that 40,000 to 50,000 barrels are burned annually. It is 

 much to be preferred to the Trenton beds which are sometimes 

 burned in the inlmediate vicinity. 



In the southern portion of the district it furnishes an inferior 

 building stone, owing to its granular character, but as it undergoes 

 modification farther north, it becomes better suited to the purposes 

 of construction. At "Waupun, Oshkosh and other localities, it is 

 rough-dressed for course-work with very satisfactory results. At 

 other points, especially Duck Creek and Kaukauna, the heavy beds 

 are well suited to the more massive kinds of masonry, and have been 

 used in the construction of the government works in that region. 



Distribution and Local Details. The more exact surface distribu- 

 tion of the Galena limestone is shown on the maps of the accompa- 

 nying atlas. Viewed in a comprehensive way the formation may be 

 said to constitute a broad, nearly north and south belt, having a jag- 

 ged, irregular outline, and forming the floor of the great Rock river 

 and Green Bay valley. 



Beginning at the south, according to our habit, we find on the west side of Rock river, 

 in Rock county, about a dozen small areas of this formation, capping the higher prom- 

 inences. Only a few feet of the base of the formation are present at these points. 



In the eastern part of Rock county, and the western part of Walworth county, the 

 Galena limestone has a more ample development, though largely concealed by drift. The 

 rock in this region has essentially the same characteristics that distinguish it in the Lead 

 region, being a rather heavy bedded, coarse, uneven textured, granular, buff dolomite, 

 containing more or less of chert, and weathering to a very rough exterior. Fossils are 

 not abundant, and are usually in the condition of obscure casts. The most extensive 

 exposures are found where the westward flowing streams have formed gorges in crossing 

 the strata. 



The Western Union Railway passes through one of these, in the town of Turtle, 

 about midway between Beloit and Clinton Junction, and has added several fine cuts to 

 the natural exposures made by the stream. 



In the town of Bradford, the Turtle creek has excavated a passage through this for- 

 mation, leaving vertical escarpments of moderate altitude, surmounted by steep slopes, 

 rising from 80 feet to 100 feet above the stream. Fissures analogous to those of the 

 Lead region occur here, but no trustworthy indication of valuable lead deposits were 

 seen. A few fossils were collected here, including Receptaculites Otceni, an undeter- 



