178 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



residuum of decomposed limestones, chiefly the so-called Oolite of 

 the Salem quarries, which form the surface rocks of the region. This 

 clay is very fossiliferous, and specimens from it are found in many 

 collections, in some labeled "Warsaw" and in others "St. Louis." 

 These names mean here the same thing — a bed of foraminiferal 

 limestone and the clay composed of its decomposed remams, char- 

 acterized by a great abundance of Pentremites conoideus, usually 

 called Warsaw by the Indiana geologists and often St. Louis by 

 others. It is immediately underlaid by the Keokuk, which is 

 exposed in some places, as in the railroad cut at Spergen Hill, and 

 from the erosion of which its fossils have also sometimes been mingled 

 in the same red clay and have taken on its color. A few have been 

 obtained directly from the rocks and are of its original bluish-gray 

 color. Therefore, wliile the great majority of the fossils labeled 

 "Spergen Hill" are doubtless derived from the Spergen beds, it is 

 always possible to find a true Keokuk species among them. 



Returning now after this digression to the Knobstone, the later 

 Indiana geologists did not adhere to its distinct separation from the 

 beds above it, as was done by those of 1874-85, but the Geological 

 Survey of that state ^ has extended it so as to definitely include, in 

 the north, the typical Keokuk crinoid beds of Crawfordsville and 

 Indian Creek in Montgomery County. 



There being thus included in this formation, in all three of the 

 states rnentioned, crinoidal beds yielding species of a true Keokuk 

 fauna correlating strictly with the occurrences at the typical locali- 

 ties in Iowa and Illinois, it came to pass that the entire so-called 

 j " Knobstone" of Indiana and Kentucky, and TuUahoma of Tennessee, 

 have been regarded by some geologists as belonging to the Keokuk 

 epoch, and collectors labeled their fossils derived from it indiscrimi- 

 nately as "Keokuk." AU the sp'ecies described by Miller and Gurley 

 from these beds have been referred to the Keokuk; and S. A. Miller 

 went so far as to claim that the Waverly beds at Richfield, Oliio, also 

 belong to the Keokuk; and in the second Appendix to his North 

 American Geology and Paleontology, 1897, he referred all the 

 species of crinoids described by Hall from that locality to that 

 horizon. (See also Bull. No. 12, 111. State Mus,, p. 11.) 



This prevalent conception of the stratigraphy of these beds has 

 completely ignored the possibility of the prolific Kinderhook and 

 Burlington series being represented in them, somewhere between the 

 Black Slate and the Upper Siliceous limestones of undoubted Keokuk 

 equivalency — and it illustrates how, even in science, people will often 

 go on following the leader without knowdng why. 



Now, to the systematic student of the crinoids, seeking to find out 

 sometliing of their actual geologic succession and phylogenetic 



» Twenty-sixth report, for 1901, pp. 263, 272. 



