48 University Geological Surrey of Kansas. 



any part of the shaft, together with the other characters de- 

 scribed, distinguish this species from all others." 



Range and distribution : Upper Coal Measures ; Topeka lime- 

 stone, Topeka. 



Our specimen is a single spine with the proximal end buried 

 in the matrix, the distal three-fourths being exposed. The ex- 

 posed part agrees more closely with this species than any other 

 yet described, and it is provisionally referred to it. 



Archseocidaris agassizi. Plate VIII, figs. 6-6e. 



Archceocidaris agassizi, Hall, Geol. Iowa, i, pt. n, p. 698, pi. xxvi, If. 

 la-d, (1858 ) : Keyes, Geol. Surv. Mo., iv, p. 127, pi. xv, f. 5, (1894); 

 Jackson, Bull. Geol. Soc. Amer., vn, p. 213, (1896); Keyes, Proc. Iowa 

 Acad. Sci., n, p. 185, pi. xvm, f. 5, (1895). 



Hall's description : " Body unknown ; plates small, hexago- 

 nal, except those adjacent to the ambulacral area, which are a 

 little rounded on that side, becoming pentagonal; central tu- 

 bercle slender, elongated, tubuliform, and projecting above the 

 surrounding annulation, the latter abruptly elevated, and leav- 

 ing, between its inner face and the central tubercle, a deep 

 cavity. Surface of the plate, immediately around the annula- 

 tion, elevated in a distinct low, annular ridge, beyond which it 

 is depressed and again elevated towards the margin, which is 

 ornamented by a series of low T elongated nodes. Spines elon- 

 gated, compressed, contracted below and swelling out above, 

 so that the greatest diameter is about one-third the length 

 above the base ; from this point very gradually tapering to the 

 summit. Surface of the lower contracted portion smooth, rau- 

 cronate above, with small spiniform tubercles, which, on the 

 lower part, are arranged in somewhat distant curving annulat- 

 ing rows, becoming more curved above, or in oblique ascending 

 rows, giving a quincunx order. Point of attachment somewhat 

 elongate, the thickened annulation strongly striate/' 



Range and distribution : Upper Coal Measures ; Topeka. 



This species was described from the Burlington by Hall. We 

 would hardly expect Coal Measures specimens to be conspecific 

 with the Burlington, but I am unable to detect any differences 

 that could be called specific in our specimens, which consist of 



