108 



CARBONIFEROUS LIMESTONES 



below the same, warrant the opinion that this coal, though at a lower level, corre- 

 sponds to coal-beds Nos. 7 and 9, near Farmington. 



Discoveries of coal are reported to have been made on Indian Creek, and at a 

 point about three-quarters of a mile below Farmington, and one mile west of the 

 Des Moines. 



At a mill-site on Indian Creek, about three-quarters of a mile above its mouth, 

 no coal is visible ; the section presenting the following members only of the upper 

 carboniferous limestone series, all below the coal-beds : 



Feet. 



1. Overhanging ledges of sandstone, cellular and rugged at base (c') ; . 15 



2. Concretionary masses of impure magnesian limestone and blocks of sand- 

 stone ; crystals of selenite disseminated; marly earth in the interstices (!>'), 15 



3. Band of same, more regularly bedded, ..... 5 



4. Soft, marly, and argillaceous beds, ..... 5 



5. Top of the geodiferous beds exposed (r/'J. 



The member b' is here much more irregular, both in composition and structure, 

 than is usual ; and, at this locality, it is useless for the purposes of construction. 

 Two miles above Farmington it is much more uniform and solid ; though a portion 

 of the rock has that peculiar tubular and cellular structure, by which it is charac- 

 terized at several localities higher up the Des Moines. 



On the waters of Indian Creek, near a Mr. Wilson's, there is said to be coal ; but 

 I had no opportunity personally to examine it. 



About half a mile from the Des Moines, near the line between Sections 25 and 

 26, Township 68 north, and Range 8 west, of the 5th Principal Meridian, on the 

 farm of a Mr. Slaughter, a seam of coal is worked, about two feet in thickness, 

 and occurring on elevated ground, within a few feet of the surface, it is covered by 

 bituminous shale and soil. The quality is equal to that of any of the seams 

 heretofore noticed. 



The beds which immediately underlie it are not exposed ; but, a few rods from 

 the coal-pit, fifteen or twenty feet down the descent of a steep hill, limestone shows 

 itself; and at a quarry a few hundred yards further, Section No. 10, D, is exposed. 



The various members, however, will be more distinctly recognised in the follow- 

 ing table : 



THICKNESS OF STRATA. 



l'ect. Inches. 



1. 



Eveu-bodded limestone (/'), 



. 2| to 3 



•) 



White gritstone (e') ..... 



. 2 to 3 



3. 



Marly, schistose layers, with silicate of iron, 



6 



4. 



Compact and obscurely oolitic white and light-gray limestone, 



. 12 to 13 



5. 



Concretionary magnesian limestone, 



7 to 8 



6. 



Cellular, close-textured, concretionary limestone (V'), 



5 



7. 



Bufl 7 and flesh-coloured, close-textured, magnesian limestone, 



20 



8. 



Concretionary magnesian rock, mixed with marl, 



7 



9. 



Pebbly sandstones (c'), ..... 



4 6 



10. 



Limestone containing Aulopoira forms the bed of the creel;, 



(?) 



