12 REPORT OF THE 



inaugurated within a little more than a year after her admis- 

 sion into the Union, and prosecuted, consequently, in the midst 

 of the greatest embarrassments. But though the work was 

 unavoidably arduous for the geologist, and expensive for the 

 State, it served to acquaint the world, at an early day, with 

 many of the sources of our mineral wealth, and to awaken and 

 maintain a lively desire for more full and definite information 

 relative to the Coal, Salt, Gypsum, Copper and Iron, of which 

 the published Reports of Progress had afforded hasty glimpses. 

 Dr. Houghton's Report, published in 1841, furnished the world 

 with the first definite information relative to the occurrence of 

 native copper in place, on Lake Superior ;* and the promise of 

 wealth now so rapidly growing up in that region, has been to 

 a great extent created by the attention drawn in that direction 

 by this Report of my lamented predecessor. 



The subjoined table, setting forth the order of arrangement 

 of the rocks of the State, as compiled from Dr. Houghton's 

 Annual Reports, and those of his assistants, will perhaps suffi- 

 ciently extend, for the present occasion, this historical reference 

 to the former State Geological Survey. 



Succession of Strata in Michigan, as published in 1838—41, 

 Arranged in Descending order. 



XXXI. Recent Alluvions, (Hubbard, Rep't 1841, p. 122.) 

 XXX. Ancient Alluvions, (lb. 120.) 

 XXIX. Erratic Block Group or Diluviums, (lb. 115.) 

 XXVIII. Tertiary Clays. (Houghton, 1839, p. IT ; 1841, p. 43 ; 



Hubbard, 1841, p. 123.) 

 XXVII. Brown or Gray Sandstone. (Douglass, 1840, p. 69; 



Hubbard, 1841, p. 130.) 

 XXVI. Argillaceous Iron Ore in thin included beds, (lb.) 

 XXV. Coal Strata, alternating with friable, slaty sandstone, 



and thick beds of black shale and slate, (lb.) 

 XXIV. Red or variegated sandstone. (Douglass, 1840, p. 10; 



Hubbard, 1841, p. 129.) 



♦Whitney 'g lletalic Wealth of the United States, p. 248. 



