84 IOWA ACADEMY OP SCIENCES. 



Cherokee Shales. — Little attempt has been made to designate, 

 by geographical names, the basal portion of the lower coal 

 measures. Recently Haworth and Kirk* have proposed the 

 name Cherokee. While it was not formally nor properly 

 defined at first as a formation name, subsequent descriptionf 

 leaves practically no doubt as to its extension. The name had 

 been previously used by Jenny J for the lead-bearing formations 

 of the Mississippian series of southwest Missouri, but only inci- 

 dentally. Before this author proposed formally to use the title 

 in this way, the term had been appropriated in another sense. 

 Moreover, Cherokee, as applied to the lead-bearing rocks, 

 covers an indefinite sequence of beds, for which specific titles 

 that are well defined had been already widely adopted; so 

 that even if the term in Jenny's sense had been formally sug- 

 gested it could scarcely be considered as having priority. In 

 this sense also, the term has nowhere been accepted as a geo- 

 logical name, while it has been practically refused recognition 

 by all who have had occasion to refer to it, either directly or 

 indirectly. 



Henrietta Limestones. — The name Henrietta was used by Mar- 

 but§ for a subdivision of the coal measures which gives rise, in 

 southwest Missouri, to a prominent relief feature called the 

 Henrietta escarpment. It consists of several limestone beds 

 of great persistency, separated by shales, but presenting a 

 sharp contrast to the immediately underlying and overlying 

 formations, which consist of shale and sandstones. 



In southeastern Kansas it embraces of Swallow's section || 

 essentially numbers 203 to 217, or from the top of the Pawnee 

 limestone down to the cement rock under the Fort Scott lime- 

 stone. In the more recent references! to the sebeds the same 

 limestones are recognized, but the lower bed is termed the 

 Oswego limestone. 



In southern Iowa the limestone in the lower part of Bain's 

 Appanoose formation which contains the great Mystic coal 

 seam, appears to be the real northern extension of the Hen- 

 rietta. 



Marais des Cygnes Shales. — There is considerable difficulty in 

 determining just what term should be applied to the shales 



* Kansas Univ. Quart., Vol. II, p. 103, 1894. 

 +Dnlv. Geol. Sur. Kansas, Vol. I, p. 150, 1896. 



* Trans. Am. Inst. Min. Eng., Vol. XXII, p. 171, 1894. 

 § Missouri Geol. Sur., Vol. X, p. 44, 1896. 



II Kansas Geol. Sur., Prelim. Rept., pp. 24-25, 1866. 

 1 University Geol. Sur. Kansas, Vol. I, p. 151, 1898, 



