300 GEOLOGY OF EASTERN WISCONSIN. 



Ortlioceras junoeum. Worm borings. 



Orthooeras planoconvexum. Illsenus ovatus. 



Orthoceras Beloitense. Asaphus Barxaudi. 



Orthoceras 2 ep. undes. Asaphus lowensis. 



Orthoceras vertebrale. Cerauras pleurexanthemus. 



Endoceras annulatum. Encrinuruo sp. undes. 



Endoceras proteiforme. Leperditia fabulites. 

 Gonioceras anoeps. 



In the vicinity of Janesville are a number of extensive quarries and natural expo- 

 sures that display the three lower members of the formation quite extensively. At the 

 quarry, a mile and a half west of the city we find, at the base, heavy buff layers, con- 

 taining but few fossils, and representing the Lower Buff beds. The complete thickness 

 is not shown. On these repose thinner bedded, eminently fossiliferous, blue and gray 

 beds attended with shaly layers and seams. These are the Lower Blue beds, in thick- 

 ness, 22 feet 9 inches. These support about 13 feet of hght buff colored Hmestone, of 

 uneven structure — owing to earthy or soft granular spots and occasional cavities — rather 

 irregular fracture, giving an earthy sm-face with crystalline spangles, and containing 

 but few fossils. Beds one foot or less in thickness. These constitute the lower portion 

 of the Upper Buff beds. The following species were observed at this point, nearly all 

 belonging to the Blue beds: Buthotrephis, CJueietes lycoperdon, Crinoid stems, Stic- 

 topora (two new species), Ptilodictya, Trematopora, Lingula atteniiata, Orthis perveto, 

 0. trkenaria. 0. sp. new (like 0. testudinaria), Streptorhynchus defleetum, Strophomena 

 camerata, S. incrassata, Ehynchon-aella, n. sp., Ambonychia lamellosa, Tellinomya n 

 suta, Cypricardites rotimdatus, C. ventricosus , Modiolopsis plana, Helicotoma planulata, 

 Baphistoma Untieularis, Trochonema umbilicatum, MarcMsonia helicteres, M. trkari- 

 nata, Pleurotomaria suhconica, Bucanki, n. sp., Pterotheca attenuata, HyoUthes Baconi, 

 n. sp., Orthoceras junceum, 0. vertehrale, 0.,n. sp., Endoceras, Proteiforme, Cyrtoceras 

 Pamlum ? Gomphoceras ? Asaphus Barrandi, Illieniis ovatus, Ceraurus pleurexanthe- 

 mus, Leperditia fabulites and Beyrichia. 



At the lower railroad bridge at Janesville, the whole of the Lower Buff limestone is 

 shown resting upon the St. Peters sandstone, and overlaid by about 30 feet of the higher 

 beds, which are here less fossiliferous than usual. A section of this exposm'e is given in 

 the report of 1862. About two miles above the city, Rock river cuts through the lower 

 part of the formation and into the St. Peters sandstone, and a ravine coming in on the 

 east, through which the road ascends from the river, exposes a large part of the higher 

 strata, so that by combining the sections, nearly the whole of the series may be studied. 

 Fossils are abundant in the usual layers. 



Farther up the river, above Fulton Center, the lower strata crown the bluffs with 

 weather-worn outliers, while nearer the water's edge the St. Peters sandstone discovers 

 itself. They become somewhat cavernous at one point, a rare feature in this region. 

 The following fossils were collected along the ledges on the west side of the river: 

 Chcetetes, Streptelasma corniculum, Stictopora, n. sp., Orthis pen-eta, 0. trkenaria, 

 Streptorhynchus defleetum, Strophomena camerata 9 S. incrassata, Rhynchonella, Telli- 

 nomya nasuta, Cypricardites Canadensis, C. reciirostris, C. rotundatus, C. ventricosus, 

 Modiolopsis superba, Baphistoma lenticularis, Trochonema ambiguum, Pleurotomaria 

 suhconica, Murchisonia tricarinata, Bucania bidorsata, Pterotheca attenuata, Orthoceras 

 junceum, 0. vertebrate, Ormoceras, Illcenus taurus, Leperditia fabulites. 



The lower beds are also exposed at the outlet of Lake Koshkonong. In the west- 

 em part of Rock county there are numerous outcroppings of this formation, most fre- 

 quently of the lower beds; but occasionally also of the higher ones. The railway cut 

 near Magnolia station exposes the Lower Buff beds, and furnishes an excellent oppor- 



