40 C. S. PROSSER — PERMO-CARBONIFEROUS AND PERMIAN ROCKS. 



ing to the same formation as could be expected when we take into con- 

 sideration the distance between them. 



Meek and Hay den reported some of the fossils of this shale from the 

 "bluish, light gray and brown clays, with occasional layers Of magne- 

 sian limestone," which they described as 35 feet thick on top of the Man- 

 hattan stone and exposed at the same locality 10 miles below Fort Riley. 

 They mentioned Chonetes mucronata, Orthisina umbracidum (?) [probably 

 specimens of Derby a^, Monotis, Fasulina, etcetera.* 



Swallow gives 38 feet of " blue, brown and purple marls, some very 

 much cancellated, and a few beds of thin limestone " exposed on Cotton- 

 wood and Clarke's creek, in which are ^^ Chonetes, Productus costatoides, 

 Orthisina missouriensis \_Mee'kella striato-costata] and umbraculum (?), Syno- 

 cladia, Archseocidaris and Euomiphahisy '\ 



Correlation of the Manhattan with the Cottonwood Stone. — Neither Meek 

 and Hayden nor Swallow called attention to the marked stratigraphic 

 and paleontologic characteristics of the Manhattan stone and shale, 

 which are the same for the Cottonwood limestone and shale in the Cot- 

 tonwood valley. I have described the importance of this horizon in the 

 Cottonwood valley and proposed the name Cottonivood formation for the 

 limestone and overlying fossiliferous shales. There seems no question 

 but that the same formation (Cottonwood) is represented by the Man- 

 hattan stone and shales, to which, therefore, the same name should be 

 applied. J 



As far as observed, this is the most distinctly marked formation in the 

 upper Paleozoic rocks of Kansas, and probably defines a horizon which 

 may be readily traced across the state, and will be of great assistance in 

 dividing this series of rocks for the purpose of mapping. 



Near the summit of hills or where there is a gentle slope the shale is 

 often eroded and the massive limestone simply remains, but usually a 

 little careful search will reveal the yellowish, fossiliferous shale in some 

 run or cut with specimens of Chonetes granidifera, Owen ; Athyris subtilita 

 (Hall), NcAvb. ; Productus semireticulatus (Martin), cle Koninck, etcetera. 

 Locally this limestone has been known for a long time as the Manhattan 

 limestone,§ and if we bear in mind the fact that it belongs in the Cotton- 

 wood formation, this name may be used for that region. 



*Proc. Acad. Nat. Sci., Phila., vol. xi, p. 17. 



t Prelim. Kept. Geol. Surv. Kansas, pp. 15, 16. 



J Since the preceding part of this paper was written I have traced the Cottonwood formation (the 

 limestone and shale) across the country from Cottonwood Falls to Manhattan. The formation 

 reaches the Neosho valley near Dunlap, follows the river toward Council Grove, from there extends 

 northeasterly across the high ground near Bushong and Eskridge to the Mill creek valley above 

 Alma, and then northwesterly to Manhattan. 



g Since the above was written Mr Charles D. Walcott has informed me that Manhattan could 

 not be used as a name of a formation, since it is preoccupied by the " Manhattan gneiss " near New 

 York city. 



