STATK GEOLOGIST. 15 



(b) Blue clay with iron pyrites, (Douglas, 1841, 



pp LOO.) 

 (a) Light blue Limestone. 

 B. Black bituminous Limestone. (Douglas, 1841, pp. 



LOS, K>3.) 

 A. Blue limestone. (lb.) 

 XI. Mackinac Limestone, (Douglas, 1841, p. 102, 103,)— 

 •• ftfanitoulin Portion of Upper Limerock. 11 (Hough- 

 ; tO, pp. L9, II. 

 X. ypiferoua Portioi er Limerock. (Houghton, 



1840, pp. L9j M. 



IX. Pentamerus Portion of Upper Limerock. (Ih.) 



¥111. I. »w r Limerock and Shales. (Houghton, 1840, p. 1G.) 



VII. (Houghton, L841j p. 20.) 



VI. Upper] tdstone. (Houghton, 1841, p. 19;) Not 



conformable with next stratum. 

 V. wtr, or Red me and Shales. (Houghton, 



1841, p. 110.) 



IV. Mixed l irate and Sandstone. (Ib.)A 



III. e. (II). 17. )n 



II. Ifetamorphic Rocks. (lb. 16. )c 



I. Primary Rocks. (lb. 15 )d 



' : than a year after the suspension of the survey 



under Dr. Houghton, Congri ed an act, approved March 



rovisions for the d < xploration 



of th. t rior Land District, organized by the same act. 



P. Jackson was appointed by the Secretary 



of the Treasur cute the required Bun 



r having spent ; >na in the prosecution of this 



ated a rep' >rt of 801 and resigned his 



commission. In the meantime, the surve; continued, and 



itly completed by v rand Whitney, United 



Their Report, of 22 I | ' »pper 



Miss, and Doc. lMJ-^0, Part III. Alio, Scnato Doc. 1st 



vm m 



