NORTHERN AND SOUTHERN KINDERHOOK FAUNAS 619 



typical form of 0. inaequalis, and approach more closely to the 

 0. chemungensis of the middle and upper Devonian faunas. 

 Chonetes geniculates White. Several specimens of a small, 

 finely marked Chonetes, although imperfectly preserved, seem 

 to represent this species, which is typically a member of the 

 Louisiana Limestone fauna. 



Chonetes cf. C. ornatus Shum. In the original description of 

 C. ornatus the typical specimens were said to be from the Chou- 

 teau Limestone of central Missouri, and from what is now known 

 as the Louisiana Limestone of northeastern Missouri. The 

 figures of the species, published with the original description, 

 do not adequately illustrate the specimens from either of these 

 localities. Extensive collections of more recent date have 

 shown that the Chouteau Limestone and Louisiana Limestone 

 specimens belong to distinct species, although both are char- 

 acterized by the peculiar concentric markings upon which the 

 species, as originally described, was mainly established. The 

 Chouteau Limestone specimens prove to be identical with the 

 species from the Kinderhook Oolite of Burlington, Iowa, which 

 was described by Norwood and Pratton as C. logani. The 

 Louisiana Limestone shell attains a larger size at maturity, is 

 marked with coarser and more angular plications, and is usually 

 proportionately broader than C. logani; and the name C. 

 ornatus may be restricted to this species. The specimens 

 from Kinderhook are all internal casts and do not well preserve 

 the specific characters, but they seem to agree more closely 

 with the specimens of C. ornatus from the Louisiana Limestone 

 than with any other species. The specimens somewhat resemble 

 those from the Chonopectus fauna from Burlington, Iowa, 

 identified as Chonetes sp. undet., 1 and they may be identical. 

 Chonetes cf. C. illinoisensis Wor. A third species of Chonetes 

 occurs rarely in the Kinderhook fauna. It is larger than either 

 of the others and is marked by finer radiating costae, there 

 being about 10c around the margin of a shell i5.5 mm broad. 

 This shell has been identified provisionally with C. illinoisensis, 

 as it has the general form and proportions of that species, and 

 agrees more closely with it in all respects than with any other. 



I Weller, loc. cit.. p. 69, Plate 1, Fig. 15. 



