NO. 1141. FOSSIL CYC ADS FROM TIUC BLACK HILLS— WARD. 223 



but tending to an arrangement in vertical rows one above another with 

 a trend different from that of either of the rows of leaf scars, i)rqject- 

 ing beyond tlic leaf bases to which they bear no resemblance, ronndcd or 

 elliptical, 3 to cm. in diameter, never cavitous, usually exhibiting 

 concentrically arranged scars, the circular central jwrtion inclosed in a 

 tube surrounded by involucral bract scars occupied by the bases of the 

 bracts which i)rojeet in miniature imitation of the leaf bases, the cen- 

 tral portion sometimes occupied by small cylindrical bodies or rods 1 

 mm. in diameter and 1 to 5 mm. long, (consisting of nearly i)ur(; quartz; 

 armor 5 cm. tliicU, definitely separated from the axis by a porous liber 

 zone of appreciable thickness; cortical parenchyma 15 mm. thick; sec- 

 ondary wood 4 cm. thick consisting of two distinct rings of about erpial 

 thi(rkness sci)arated by a peculiar scolloped line, apparently caused 

 by the convex edges of woody wedges 5 mm. thick separated l)y thin 

 medullary rays; medulla cm. in diameter, somewhat lieterogeneous 

 or chambered in structure. 



This si)ecies is represented by tlie single si>e<;imen No. 80 of the Yale 

 collection. It has close allinities ou the one hand with 6'. iiigcun and 

 on the other with C. stilhcdli, while all tliese are related to G. vicbridci^ 

 but it is impossible to refer it to any of these 8i)0(ies. 



CYCADEOIDEA STILLWELLI, new species. 



Trunks small, cylindrical, or more or less laterally <;ompressed, 30 to 

 40 cm. high, 15 to 25 cm. in diameter, 40 to 70 cm. in girth, reddish or 

 light colored externally, cherfcy, ilinty, or more or less agatized within, 

 simi)le, or bearing a few small branches in the form of i)roJections or 

 protuberances, short conical at the summit, with a luitural depression 

 at the apex, studded with small polygoiuil scars and a gentle swelling 

 at the center; organs of the armor nearly horizontal ; leaf scars arranged 

 in two series of spiral rows, those from left to right making an angle 

 of 40° to 50°, those from right to left of 30^ to 50^ with the axis of the 

 trunk; leaf scars normally almost exactly rhombic or diamond-shaped, 

 but with a tendency on the one hand to the rounding of tlie vertical 

 angles and on the other to the incurving of the sides so as to exaggerate 

 the acuteness of the lateral ones, this sometimes very marked; s<;ars 

 snuiU, 20 to 25 mm. wide, 15 to 20 mm. high, occasionally almost as 

 high as wide, the lateral diagonals about horizontal and the vertical 

 ones perpendicular to them, or vertical; leaf bases always present, till- 

 ing the scars, often projecting, sometimes considerably, the petioles 

 disarticulating at several diiferent points by means of a diaphragm 

 which forms a thin layer over the exposed summits, the occasional 

 absence of which leaves a rough spongy or porous structure; vascular 

 bundles arranged in two rows, one near the margin and parallel to it, 

 the other forming an elliptical ring at tlie center 3 by 4 mm. in diam- 

 eter, both rows usually appearing in the form of denticulate ridges: 

 rameutaceous walls very thin, 1 to 2 mm., often sharp at the surface, 



