180 HALL AND SARDESON — THE MAGNESIAN SERIES. 



tion of this bed was given, and not even a locality where its typical 

 development could be seen was named. Merely the existence of such an 

 interpolated sandstone between the upper layers, " the Willow river bed," 

 and the more massive portion of the Magnesian limestone was announced. 



PHYSICAL CHARACTERS. 



In 1883 Warren Upham, in discussing the " Shakopee epoch," observed 

 that the — 



' ' formation incloses a more or less persistent layer of sandstone 20 feet thick in the 

 deep well at Elevator B, in Saint Paul, which is probably the Jordan sandstone of 

 Houston and Fillmore counties, except perhaps at Lanesboro, and of Olmsted 

 county, except perhaps at Quincy." * 



This is usually a pure white quartz-sand. It is loosely cemented, in- 

 distinctly stratified and indistinctly separated from the underlying 

 Oneota, a fact which points strongly to the lack of any line of separation 

 from that formation save the lithologic one. No fossils whatever have 

 been found to aid in its closer identification and reference. At Saint 

 Paul, Upham found this sandstone 20 feet in thickness ; at Lewiston it is 

 12 feet ; at Mankato, 6 feet, and is interlaminated with a green unctuous 

 shale. 



So far as the observations of the writers go, the New Richmond sand- 

 stone is entirely devoid of fossils. Its delimitation from the Oneota is 

 therefore wholly lithologic. Inasmuch as in other cases — for instance, 

 between the Jordan and Oneota— the transition is through successively 

 alternating strata, the New Richmond may prove to be an arenaceous 

 cap to the Oneota beds when further localities have been explored or 

 fossils have been discovered. 



The Shakopee Dolomite. 

 localities. 



In Minnesota : Shakopee, Cannon Falls, Northfield, Clay Bank, and 

 Utica. 



In Wisconsin : River Falls ; on the Willow river, especially at Burk- 

 harts Mills ; Prairie du Chien, Argyle, and Pickett station. 



In Iowa : McGregor and Giard. 



PHYSICAL CHARACTERS. 



The Shakopee formation is mainly a dolomite of various texture — fine, 

 soft, compact, crystalline, subcrystalline, rough, porous, etcetera. In 



*See also Paleozoic Formations of Southeastern Minnesota, Hall and Sardeson : Bull. Geol. Soc 

 Am., vol. 3, 1892, p. 341. 



