342 GEOLOGY OF EASTERN WISCONSIN. 



represents the better quality found in the rock pile at the furnace. By 

 comparison with that from Taycheedah, it will be seen that the lime- 

 stone used is not the purest that is accessible to Lake Winnebago, and 

 this fact may be worthy of the attention of those interested. 



For the purposes of ordinary masonry, this formation furnishes an 

 abundance of readily accessible material, and it is extensively used 

 for such purposes. The granular stratum furnishes an excellent stone 

 for cutting. Its rich cream color gives it a very pleasing effect. 

 Rock obtained east of Horicon marsh is wrought at the State Prison, 

 at "Waupun, and quarries have been opened upon this stratum, east of 

 Found du Lac, from which a supply of cut stone, for that city and 

 other points, is obtained. 



Distribution, and Local Descriptions. By consulting the maps, 

 it will be seen that these beds occupy an irregular belt, stretching in 

 a nearly north and south direction, from the Illinois line, in Wai- 

 worth county, to near the extremity of the peninsula east of Green 

 Bay, where it dips beneath the surface of that body of water. Most 

 of the localities here mentioned lie on the extreme western margin 

 of this belt, and show the projecting edge of the formation. 



The point at which the formation enters this state from Illinois, or leaves it in that 

 direction, if you please, is deeply concealed by drift, but there is abundant reason for 

 believing that it crosses the line from the towns of Walworth and Linn, as represented 

 on the map. 



On the north side of Lake Geneva, the limestone approaches the surface, but does not 

 actually outcrop. The most southerly point where the western limit of these beds is ac- 

 curately determined by outcrop is in the S. W. qr. of Sec. 10, town of Eagle in Wau- 

 kesha county. South of this point, the outline, as mapped, is based upon topographical 

 and drift evidence, and can only be regarded as approximate. At Hinckley's quarry, in 

 the above-named section, four feet of thin bedded, impure magnesian limestone, having 

 an even fracture and light, yellowish gray color, blotched with green in places, espec- 

 ially between the layers, form the base of the quarry, and rest upon the Cincinnati shale. 

 Above these are nine feet of thicker bedded limestone of coarser and more irregular tex- 

 ture, and marked by walnut-sized cavities, lined with yellow granular matter. 



These beds, when exposed in natural ledges, as they are in the vicinity, weather to a 

 very rough, ragged exterior, due to the irregularities of their structure. 



In this region, the great drift moraine, previously described as the Kettle Range, over- 

 lies this formation, and it is only here and there that it displays itself. Near Hinckley's 

 quarry, the lodge swings round to the east, and disappears beneath the drift ridges. It 

 emerges again in Sees. 11 and 14 of the town of Ottawa. The rock here is char- 

 acterized by conspicuous nodules of white chert, which are very abundant in some 

 layers. 



At Hunter's quarry (Sec. 11, S. E. qr.), the lower three feet exposed is a moderately 

 hard, compact, gray, magnesian limestone, marked with iron stains. Upon this lies a 

 somewhat peculiar shaly layer, which may be described as chipstone imbedded in a 

 clayey material. Above this are two and a half feet of more solid rock, the upper por- 

 tion of which is cherty. This is overlaid by another shaly, or chipstone layer, similar to 

 that below, but cherty; and this in turn is surmounted by a few rotten buff layers that 



