368 GEOLOGY OF EASTERN WISCONSIN. 



drift, and that exposures of the rock are few and of limited extent, and it is further to 

 be remembered that these are distinctions between subordinate divisions of the same 

 epoch, and involve discriminations not often attempted with equal detail. 



In the norlhsrn counties, the formjtion is nrich m:>re uniform, both in the character 

 of the rock and of its organic contents. As a type, or at least standard of comparison, 

 we may select a limited but characteristic section from the town of Kewaunee (T. 23, 

 R. 24, Sec. 14, S. hf). 



1. Top Layer. A hard, compact, rather fine-grained, grayish white, even 



bedded dolomite, of somewhat uneven texture, weathering into 

 creases, rather than pits, and quite fossiliferous, especially abound- 

 ing in Brachiopods 1 ft 10 in. 



2. Somewhat similar to the above, but coarser, softer, more uneven in 



texture, more inclined to be granular, and containing fewer fossils. 



It weathers into pits rather than creases 1 ft 2 in. 



3. Similar to the last, but still more soft and granular, and more irregu- 



lar in bedding and texture 2 ft 4 in. 



4. Similar to the above 3 ft 6 in. 



5. Thin layers, belonging to the Upper Coral beds 11 ft. 



Although some of these layers are described as soft and granular, they do not possess 



these qualities in the same degree as that at Cedarburg and similar localities. 



At Wilmot's quarry S. E. qr., Sec. 32, Pierce (T. 24, R. 24), about five miles from the 

 above, we find a rather soft, somewhat granular dolomite of subcrystalline structure, ir- 

 regular fracture, rather thick, scarcely even beds, of bluish and grayish white color, 

 with occasional stains of yellow and red, weathering to a yellow or buff. 



All of the rock referred to this formation in Kewaunee county is very similar to the 

 above. 



One more example, from near Sturgeon Bay, Sec. 9, S. E. qr., T. 27, R. 26, will 

 suffice for this portion of the formation. This outcrop consists of a -vhitish, somewhat 

 granular, porous dolomite, of subcrystalline structure. It is heavy bedded and weathers 

 into pits and creases, but not conspicuously so. The weathered surface shows white 

 lines about one-half inch in width that are usually parallel to the bedding. These cor- 

 respond to thin laminae of a more compact, homogeneous, cryptocrystalline rock, appar- 

 ently of essentially the same chemical composition as the rest. Some portions of the 

 rock instead of being granular, are close and flintlike in texture, although enclosing 

 numerous small cavities. On the average, the rock is of medium hardness and irregular 

 fracture. 



The formation throughout Door county does not essentially differ from this, except 

 that at some points it verges more toward the coarse-grained saccharoidal marbles. 



Speaking in general terms, the formation is possessed of quite constant lithological 

 characters north of Sheboygan county. 



Summation. It appears, then, that in the southern counties there 

 are three well marked classes of limestones, with intermediate grada- 

 tions, one class, consisting of very irregular, often brecciated or con 

 glomeritic dolomite, forming masses that usually appear as mounds, 

 or ridges of rock, of obscure stratification, a second class, formed of 

 pure, soft, granular dolomites, a part of them calcareous sandrock, 

 and a third class, consisting of compact, fine grained, regular, even 

 beds. We have demonstrated that the three forms change into each 

 other when traced horizontally. They were therefore formed simul- 



