]8G9.] ^ ^^ fWiiichcll. 



Gritstone series, consisting of flaggy sliales, ferruginous, somewhat thick- 

 bedded sandstones with iron-stone partings, often witli interstratified 

 blackisli or bluish sliales. Followed downward by shales of a bluish, 

 brownish or reddish color, 100 to 150 feet. 



Waverly series : — Bluish or greenish gray, fine-grained and evenly bed- 

 ded, often fossiliferous sandstones and flags, with intersti-atified brown- 

 ish shales. 200 feet. [In Knox county the Gritstone and Waverly 

 series are together 517 feet.] 



Chocolate shales, argillaceous, chocolate colored, bluish and blackish. 

 250 to 300 feet. [In Knox county this series is 450 feet.] 



Black Shale, 100 to 150 feet. [This is an abnoi'nial thickness of the Black 

 Shale in the West, and it is probable the upper portion belongs with the 

 Chocolate series.] 



In the State of Indiana the series seems to be constituted as follows -.^^ 

 Carbonifei'ous Conglomerate. 

 St. Louis Limestone, freely represented. 

 Warsaw Limestone. 

 Keokuk Group, consisting of : — 



Gray limestone and calcareous shales (Floyd county) 50 feet. Wanting 

 in Northern Indiana. 



Brown shales with geodes and nodules of hornstone. 



Knob formation or gritstones, micaceous, ferruginous, friable, with in- 

 tercalated limestones in the upper part. 150 feet or more. 

 Rockford Limestone, with Goniatites, &c. ; represented by a thin bedded 



sandstone in Northern Indiana. Wanting in Western Indiana. 

 Black Shale. 



In the State of Illinois we have the following succession of strata. ^^ 



Burlington Limestone. 



Kinderhook Group, consisting of "gritstones, sandy and argillaceous 

 shales, with thin beds of fine-grained and oolitic limestone." 100 to 200 ft. 



Black shale. "Dark blue, green, or chocolate colored shales, passing 

 locally into a black bituminous shale." [Presents in Southern and 

 Western Illinois, rather the characters of the Huron shales of Michigan. 

 May it not constitute, with the lower portion of the Kinderhook group, 

 a representation of the Portage and Chemung of New York?] 



In Iowa (at Burlington) the series of strata is the following i^s 

 No. 8. Upper Burlington Limestone. 20 feet. 

 No. 7. Lower Burlington Limestone. 30 to 50 feet. 

 No. 6. Oolitic Limestone, with fossils. 2 feet. 

 No. 5. Yellowish Sandstone with abundant casts of Brachiopods. 4 



to 6 feet. 

 No. 4. Limestone, with Brachiopods. 9 feet. 

 No. 3. Oolitic Limestone. 3 in. 



91 Hall— Trans. Assoc Amer.Geol. p. 280; Meek and Wortheti—Amer. Jour. Sci. [2] xxxii., 167; 

 Wortben— Ill.Geol. Report, vol. i., p. 116; Christy— Proc. Amer. Assoc, v., p. 76. 

 «' Worthen- Geol. Surv. 111., I., p. loS; III., p. \u>. 

 0" Hall— Iowa Geol. Rep., I., 9(1; White— lb., Append. 



