280 C. 11. KEYES DEVONIAN INTERVAL IN MISSOURI 



same geological age as the Chemung, of the New York section, consist 

 chiefly of greenish and bluish shales and yellowish sandstones. They 

 are now called the Lime Creek shales in northern Iowa, the Sweetland 

 shales in Muscatine county, in eastern Iowa, and the Kinderhook shales 

 or Hannibal shales at Burlington and in northeastern Missouri. All 

 available information now indicates, without much room for doubt, that 

 the beds of the several localities are stratigraphically one and the same 

 formation, but that at Burlington it is only the upper part of a great 

 shale terrane that is exposed to view, while on Lime and Sweetland creeks 

 it is the lower part that has been open to inspection. 



Assuming that this be true, some of the causes for the protracted con- 

 troversy which has arisen regarding the age of the beds in question may 

 be inquired into. First to present itself is the fact that the Chemung, or 

 Kinderhook of Meek and Worthen, or Chouteau group of Broadhead (not 

 of Swallow), has been invariably considered as a homogeneous geological 

 unit. When the term Kinderhook was first proposed and stated to be 

 Carboniferous in age it was, as just stated, made to cover everything in 

 the region which had been previously called Chemung. No attempt was 

 made to inquire into the matter of whether or not some part of the newly 

 named formation might not actually possess a different geological age. 

 It is known now that in the case of the original locality the lower four- 

 fifths of the Kinderhook was not critically considered, but dumped bod- 

 ily into the supposed new receptacle. The Spirifer capax beds of Mus- 

 catine, which were called Chemung by Hall, were likewise, without 

 examination, placed by Miller * in the Carboniferous. When Calvin f 

 came to inquire into the Muscatine problems he found a strange state of 

 confusion. 



When I first personally visited the Muscatine localities, it was as a 

 college student, before I even knew that there was such a thing as a 

 Kinderhook controversy. I was quite familiar with the Devonian fossils 

 of districts farther north, but I was perfectly unbiased in approaching 

 the problems relating to the geological age of the various horizons in 

 the locality under consideration. The Spirifer capax beds were deter- 

 mined not to be Carboniferous yellow sandstones at all, but yellow, 

 finely crystalline dolomites carrying the same fossils as some of the 

 Cedar Valley limestones near by and farther to the northward. 



Hall certainly did make the mistake of placing the Spirifer capax 

 beds above the green " Chemung " (Sweetland) shales, for it is now 

 demonstrated that their position is below the latter ; but it is readily 

 understood after visiting the localities how such a transposition of hori- 



*American Paleo. Foss., 1887, p. 129. 



f American Geologist, vol. iii, 1889, p. 25. 



