334 HALL AND SARDESON PALEOZOIC FORMATIONS OF MINNESOTA. 



tion of all the lands in the Mineral Point and Galena districts. ' :: * * 

 together with all the surveyed lands in the Dubuque district." ' He was 

 farther directed, as he says, "to select specimens of all the minerals of 

 much value and to forward these to Washington city, as such a collection 

 was deemed important to illustrate my official report, - ;: :;: :;: and 

 also interesting as forming the nucleus for a national cabinet."* 



This line observer and enthusiastic geologist, who labored so untiringly 

 to extend our knowledge of the geology of the northwestern states, en- 

 tered upon his labors in the upper Mississippi river valley. He lived 

 long enough to see his work develop into at least three state surveys, 

 several surveys under the United States government, and a magnificent 

 national museum at Washington. 



In the report cited,f Dr. Owen distinguished for the Northwest— 



5. The recent deposits : 



4. The Tertiary strata : 



3. The Secondary strata; 



2. The Primary fossiliferous strata : 



1. Granite and other crystalline rocks. 



Owen's more systematic work, however, was done on his return to this 

 region in 1848 for more detailed geologic explorations. In his report 

 of this work he distinguished the Paleozoic series — "The Primary fossil- 

 iferous strata '' — in ascending order! as : 



5. The Carboniferous limestones and coal fields of Iowa and Missouri ; 



4. The Cedar limestones (contemporary with the Devonian formation 

 of the English geologists) ; 



3. The Upper Magnesian limestones ; 



2. The Lower Magnesian limestones ; 



1. The Lower sandstones (the lowest protozoic strata I. 



The opinion was expressed that the Lower sandstones extend beneath 

 the drift of the lake Superior. country. Another opinion expressed by 

 Dr. Owen must not here be omitted, since it was so ac< urate a prophecy : 

 "There can now be little doubt that the whole mining region of the 

 Mineral Point and Dubuque districts of Wisconsin and Iowa is based 

 upon a syenitic and granitic platform, which would in all probability be 

 reached by penetrating to the depth of from 2,000 to 4,000 feet "^ The 

 artesian and other deep wells at La Crosse. Prairie du Chien, Mason ( ity. 

 Lansing and other points show the granitic floor to that distance south- 

 ward to be less than 1,500 feet.jj 



* Senate Document 407, 28th Cong., 1st session, 1814, pp. 12, 13. 



t [bid., p. 15. 



JReportol > Geological Survey of Wisconsin, Iowa ami Minnesota. Philadelphia, Lippineott, 



a ( ... 1852: Introduction, p. xix. 



glbid., p. 62. 



|] Bull. Minn. Acad. Nat. Sci., vol. iii, no. 1, 1889, p. 135. 



