80 T"&E OLDER MESOZOIC FLORA OF VIRGINIA. 



This is Saporta's diagnosis of the genus, and I follow it with only the 

 change of the words " on the sides," to " on, or near the sides of the mid- 

 rib." He says of these plants, very justly, that they are rare everywhere, 

 and, as yet, imperfectly known; that the leaflets were articulated to the com- 

 mon stem, and hence they appear more commonly isolated, and not attached, 

 and, further, that they mark the age of the highest development of the 

 Cycadaceous plants, and are themselves the most finished type of these 

 plants. All these statements would seem to apply to the splendid plant 

 presently to be described, and which is the only one of the genus as yet 

 found in Virginia. The oldest Sphenozamites, according to Saporta, appear 

 in the lower Oolite, they are abundant in the middle Oolite of the Venetian 

 Alps, and range as high as the upper Oolite. They are, then, plants especially 

 charactistic of the Oolite, and the discovery of so fine a specimen of the 

 genus in the Richmond Coal Field is of great importance. As there are 

 many species of the Rhaetic, either identical with those of the lower Oolite 

 or closely allied to them, it need not surprise us to find a Sphenozamites 

 among Rhaetic plants. The species now in question is, then, the oldest 

 Sphenozamites, as yet, found. 



Sphenozamites Rogersiauus, spec. nov. 



Plate XLIII, Fig. 1; Plate XUV, Figs. 1, 2; Plate XLV Figs. 1,2. 



Leaf very large, in the largest forms 1 meter at least in length ; -width, 40 to 50 

 centimeters. Midrib very strong, rigid, and woody, 1 to 1£ centimeters wide, rounded 

 in form on the lower surface, and flattened on the upper surface, strongly and irreg- 

 ularly striate and ridged. Leaflets rather remotely inserted, opposite or subopposite; 

 in the middle and lower parts of the leaf, standing at right angles to the midrib, in the 

 upper portions, becoming more and more oblique in insertion, until the terminal leaflet 

 stands on the summit of the midrib, forming the prolongation of its direction. The 

 leaflets are very large and narrowed towards the base so as to have an elliptical out- 

 line, and at the lowest part of the base are abruptly rounded off, and narrowed into a 

 very short pedicel which is obliquely inserted somewhat within the margin of the 

 midrib. They widen in a flabellate manner towards their ends so that in the mid- 

 dle and upper parts they overlap one another. They are widest at and near the 

 extremities, which are cut away obliquely from the upper part of the termination to 

 the lower part and rounded off so that the lower margin of the leaf is longer than the 

 upper one. All are bordered by a very narrow cartilaginous rim which is formed by 

 the thickening of the edge of the leaflets. While the lateral leaflets are wedge-shaped 

 with obliquely sloping terminations the terminal leaflet is exactly and symmetrically 

 wedge-shaped. The nerve-bundles, by their close approximation at the base of the 



