70 8 CHARLES S. PROSSER 



Americus limestone. — This name was given by Kirk in 1896 

 to two thin layers of limestone, separated by shale, which are 

 quarried near Americus. 1 It was also noted by Haworth and 

 Kirk in their " Neosho river section " and called "limestone sys- 

 tem No. 11." 2 The lower stratum is buff in color, very solid 

 and compact, making a good building stone with a thickness of 

 twenty-one inches, according to Smith. Then comes six feet of 

 shale with a six-inch flag limestone on top, 3 making a total 

 thickness of over eight feet, and its distribution has been 

 mapped entirely across Lyon county by Smith.' 1 On the Cot- 

 tonwood Falls quadrangle it is probable that this limestone is 

 only a few feet below water in the Cottonwood River east of 

 Elmdale. 



Elmdale formation. — This formation, the succeeding ten and 

 the lower and middle parts of the Marion, are represented on 

 the Cottonwood Falls quadrangle, which has also furnished the 

 majority of the names, and consequently these have been more 

 thoroughly studied by the writer than the preceding formations. 

 It is about 130 feet in thickness, and composed of yellowish to 

 bluish shales, with thin beds of grayish alternating limestone, 

 including two or three thicker ones. About thirty feet above 

 the base of the formation is a friable limestone with a thickness 

 in some localities of four feet, which is composed to a large 

 extent of the tests of Fiisnlina secalica Say. This stratum 

 weathers readily and leaves great numbers of Fusulina in the 

 soil. About thirty-five feet higher is another conspicuous yel- 

 lowish limestone, the center of which weathers to a rough face, 

 and from ten to fifteen feet below the top is a limestone stratum 

 from three to five feet in thickness. The formation is limited at 

 the base by the top of the Americus limestone, and at its top by 

 the base of the massive Neva limestone. It is well exposed on 

 the bluff east of Elmdale, from which town it is named. 



1 Univ. Geol. Surv. Kan., Vol. I, pp. 80, 81. 



2 Kan. Univ. Quart., Vol. II, January, 1894, p. III. 



3 Bull. Lyon Couttty Geol., pp. 3, 10. 



* Trans. Kan. Acad. Sci., Vol. XVII, 1891, p. 191 ; and Bull. Lyon County Geol., 

 p. 8. 



