Maryland Geological Survey 327 



distinct, the whole punctured with minute rhombic, triangular, or ellip- 

 tical bract scars deeply penetrating the structures; leaf bases usually 

 wanting, but sometimes nearly filling the cavities; vascular bundles few, 

 arranged in a row near the upper side of the petiole, and others scattered 

 over other parts ; petioles all reflexed or pointing downward at a strong 

 angle; reproductive organs numerous, situated directly over the leaf 

 scars, i. e., axillary, elliptical in outline, 15 mm. wide, 10 mm. high, 

 the centre occupied by the remains of the essential organs or by a circular 

 cavity where these have disappeared; bract scars small and num.erous', 

 somewhat curved and arranged concentrically, also passing out into the 

 ramentum walls; armor 3cm. to 5cm. thick; woody zone 15mm. to 

 35mm. thick, divided into two or three rings; medulla about 5 cm. in 

 dianieter, cylindrical or elliptical, according to the shape of the trunk; 

 heterogeneous in composition, being traversed by dike-like plates of a 

 hard substance dividing it into chambers, often wanting, lea\ing a hollow 

 centre to the trunk, 



Cycadeoidea Bibbinsi Ward 

 Plate XLVIII 



Cycadeoidea Bih'binsi "Ward, 1897, Proc. Biol. Soc, Washington, vol. xi, 



p. 15. 

 Cycadeoidea BidMnsi Ward, 1906, Mon. U. S. Gaol. Surv., vol. xlviii, 1905, 



p. 456, pi, Ixxxiii, fig. 3; pi. Ixxxiv, fig. 3; pi. Ixxxv; pi. Ixxxvii, figs. 



i, 2, 4, 6, 7; ii, 1, 2, 4, 8, 9, 10, 11; iii, 5, 7; iv, 2, 3, 6, 8, 11; v, 12, 15; 



pi. ixxxix, figs, i, 5; ii, 2, 5, 6; pi. ci-civ. 



Description. — Trunks large, 40 cm. to 60 cm. high, laterally com- 

 pressed, girth of largest specimen 1 m., of next in size 88 cm., shorter 

 axis of cross-section one-half to two-thirds of longer axis, contracted 

 toward the summit, terminating in a conical bud 30 cm. high, or, where 

 this is wanting, in a concave depression, thoroughly silicified throughout. 

 heavy and solid, of a dark color; all the organs of the armor nearly at 

 right angles to the axis of the trunk; leaf scars arranged spirally around 

 the trunk in imperfect quincunical order, subrhombic, the lower angle 

 much sharper than the upper, the latter sometimes reduced to a curve, 

 14 mm. high, 26 mm. wide; ramentum walls moderately thick, usually 



