St. Peter's Sandstone. 125 



It is also discussed by Professor Swezy, who mentions* the 

 occurrence of the St. Peter's sandstone at Beloit, immediately 

 beneath the Trenton. The author says: "Between the St. 

 Peter's sandstone and the Trenton limestone are eight feet, or 

 perhaps more, of transitional layers ; they include, at the 

 bottom, a foot or so of sandstone, more coarse and impure 

 than is usual with the St. Peter's ; above this five feet of 

 impure limestone and shale, and at the top two feet more of 

 coarse sandstone." Above this series comes the typical Tren- 

 ton limestone. In a diagram, presented on page 199, these 

 transitional layers are not referred to either the St. Peter's or 

 the Trenton. 



Another excellent exposure, showing transition beds be- 

 tween the Trenton and St. Peter's, occurs at Fountain, Minn. 

 This was first described by Prof. N. H. Winchell, in 1876.T 

 His section is as follows : 



SECTION NEAR FOUNTAIN ; QUARRY OF JOSEPH TAYLOR. 



FT. 



No. r. Green shale mixed with fragments of limestone 

 that are eminently fossiliferous, seen, 3 



No. 2. Limestone, of a bluish-gray color, in beds from 

 four to six inches thick, free from shale, though the layers 

 are sometimes thinly separated by shaly partings, 10 



No. 3. Arenaceous and ferruginous shale, alternating 

 horizontally with firmly cemented patches of sandstone, 2 



No. 4. Massive coarse sand ; white, excejpt where iron- 

 stained, containing irony quartzite pebbles, and fragile re- 

 mains of bivalves, 6 



No. 5. Green shale, with some arenaceous and calcare- 

 ous laminations, 3 



No. 6. Cemented sandstone, the cement being shale and 

 lime, forming, where the bluff is weathered, the floor of a 

 bench, 1 



No. 7. White sand, in beds that are about one foot thick 

 and horizontal, 6 



No. 8. A course in the sandstone more firmly cemented, 

 forming another table, but less persistent than No. 6, . . . 1 



No. 8 [9]. Massive sandstone, in some places showing an 

 oblique lamination, seen, 6 



4f Total, ' f\**i: 38 



* On some points in the geology of the region about Beloit. Wisconsin Acad. 

 Sci. Trans., Vol. V, p. 194. 



t Fourth Rept. Geol. and Nat. Hist. Sur. Minn., for 1875, 1876, pp. 40-42. 



