GALENA LIMESTONE. 



309 



mined species oi Sireptehmna, a liew species of LingnUi, Orfhis lynx, tricenaria, a, 

 Strophomena, Cypricardites rotundatus, C. subtruncatus, C. ventricosus, Baphistoma len- 

 ticularis, Trochoneina umbilkatum, a new species of Jl^itrc/jisow'a and Orthoceras j unce- 

 %im. The most southerly exposure of this formation, seen in Walworth county, was near 

 Sharon Mills. Between this point and Whitewater, deep drift conceals it. Near 

 the latter point, several quarries have been opened, from which a supply of bmlding 

 stone and Hme are derived. The rock here is of a more decided buff color than is com- 

 mon, and is marked with peculiar concentric wavy lines of a redish hue. It is soft, po- 

 rous, granular, uneven in texture, and much decomposed on the surface, but is more 

 cohesive and enduring than its appearance would indicate. There is evidence of a con- 

 siderable fauna at this point, though the preservation of the fossils is usually poor. 



The following identifications have been made, a portion of them based on specimena 

 from the private collections of Mr. L. C. Wooster: 



Eecepiactilites globosus, JR. Oweni, Astylospongia, casts of the cup of a Zaphrentie, 

 Cornulites-lili'e tubes, Lingiila quadrata, a Monomerella, OrtMs lynx, 0. perveta, or equi- 

 valvis, Streptorhynchus deltoideum, Strophomena alternata, S. camerata, large form, S. 

 camerata?, small ventricose form, Atrypa hisulcata, Ehynchonella capax, Ambonychia 

 erecta?, A. lamellosa, Cypricardites ventricosus, EapMstoma lenticularis, Trochoneina 

 umbilicatiim, Pleurotomaria, resembling P. Occidentalis, Murchisonia bellicincta, or M. 

 major; M. bicincta, and anew species, Holopea paludiniformis, H. near H. obligua, 

 Fusispira elongat-t. F. ventricosa, and a new species of Ecculiomphalus, Maclurea 

 Bigshyi?, and two n. sp. Conularia Trentonensis, Orthoceras planoconvexum, and two 

 undetermined species, Cyrtoceras (Oncoceras) plebeium, and two undetermined species. 



Passing by several minor exposm-es, we find about two miles southeast of Fort 

 Atkinson, quarries situated in the lower portion of this formation, tod a little to the 

 north (Sec. 10, S. B. qr., T. 5, R. 14), a quarry in the Upper Blue hmestone. The rook 

 from the former furnishes a good lime and an ordmary building stone. On the west 

 side of Rock river, in the towns of Jefferson and Oakland, are several patches of 

 Galena Mmestone, forming the nucleus of the promiaent hiUs of that region. On the 

 east side of the river, the heavy drift accumulations effectually conceal the foi-mation. 



About two miles north of Watertown, in the S. E. qr. of Sec. 20, town of Emmet, 

 Dodge county, is an extensive quarry displaymg this formation, which still maintains 

 the characteristics ah-eady described. Cavities in the rock are rather more than usually 

 abundant, and are usually lined with oalcite, or more rarely dolomite, and occasionaUy 

 with zinc blende or galena. Iron pyrites also occur in nodular crystallizations, many 

 of which are desulphurized in whole or in part. 



Chert, as usual, is abundant, more particulaily in the upper layers. Fossils are rare. 



An analysis by Mr. Bode of chippmgs from the several layers representing a thick- 

 ness of fifteen feet, shows the following composition: 



Carbonate of lime 54.051 



Carbonate of magnesia 44.139 



SiHca 1-564 



Alumina 00^2 



Oxide of iron ^■'^'^^ 



100.000 



From which it will be seen to be a nearly pure dolomite, aside from the cheri;, which 

 was excluded from the specimens analyzed. 



As far north as this point, the rock of this formation has maintained a very constant 

 character, and, as remarked before, closely resembles the Galena in its more typical- 

 locaUties. To the north of this point it begms to undergo a change. For twentjy-five 



