=36.= Owing to lack of detailed study of the rocks from the last described to the Cottonwood limestone, it will be necessary to combine the less important strata into groups and mention only the more important. It is a matter of regret that the rocks of this part of the Kansas river section cannot be referred with certainty to the corresponding rocks of the Neosho river and Cottonwood river sections, which have been studied by various geologists. As near as I am able to judge, No. 13 of Bennett’s Buffalo Mound section[11] corresponds to the Americus limestone near Emporia.[12] All the rocks between No. 35 and No. 13 of Bennett’s Buffalo Mound section are put under No. 36. They consist of an alternation of thin limestones and shales. These shales form a part, at least, of the “Olpe” shales of Dr. Geo. I. Adams (by permission, from his MSS.) =37.= No. 13 of Bennett’s Buffalo Mound section. Probably is the equivalent of the Americus limestone before mentioned. =38.= ELMDALE FORMATION. Prosser and Beede, MSS. Shales with occasional thin limestones, quite fossiliferous in the lower portion. This is probably the same horizon as No. 2 and No. 3, except the limestone at the top, of Prosser’s Manhattan section.[13] It is also, in all probability, the same horizon as No. 8 of my section on the South Fork of the Black Vermillion river.[14] However, the fossils from the latter place are given in a separate list. The thickness of these shales on the Kansas river and Mill creek are from 111 to 118 feet. Grouping the Mill creek and the Manhattan equivalents, we have the fossils of this horizon as follows: _Fusulina secalica_ (Say). _Lophophyllum profundum_ (Milne-Edwards and Haime) Foerste. _Chætetes?_ sp. _Crinoid_ stems and plates. _Archæocidaris_ sp. _Archæocidaris_ sp. _Dichotrypa subramosa_ Rogers, MSS. _Fistulipora nodulifera_ Meek. _Rhombopora lepidodendroides_ Meek. _Septopora biserialis_ (Swallow) Foerste. _Ambocœlia planoconvexa_ (Shumard) Hall and Clarke. _Chonetes glaber_ Geinitz. _Chonetes granulifer_ Owen. _Crania modesta_ White? _Derbya crassa_ (Meek and Hayden) Waagen. _Dielasma bovidens_ (Morton) White. _Enteletes hemiplicata_ (Hall) Hall and Clarke. _Hustedia mormoni_ (Marcou) Hall and Clarke. _Lingula umbonata_ Cox. _Meekella striaticostata_ (Cox) White and St. John. _Orbiculoidea manhattanensis_ (Meek and Hayden) Hall and Clarke. _Productus cora_ d’Orbigny. _Productus longispinus_ Sowerby. _Productus nebraskensis_ Owen. _Productus semireticulatus_ (Martin) d’Orbigny. _Productus symmetricus_ McChesney. _Pugnax utah_ (Marcou) Hall and Clarke. _Rhipidomella pecosi_ (Marcou) Hall and Clarke. _Seminula argentia_ (Shepard) Hall and Clarke. _Spirifer cameratus_ Morton. _Spiriferina cristata_ (Schlotheim) Dawson. _Allorisma subcuneatum_ Meek and Hayden. _Aviculopecten occidentalis_ (Swallow) Meek and Hayden. _Nuculana bellistriata attenuata_ Meek var. _Dawsonella meeki_ Brady? (Prosser’s identification.)