420 



PALEONTOLOGY OF OHIO. 



gin, where they slightly curve upwards, the leaf being to a slight 

 degree revolute. Thirty-five nervules are counted on the border in the 

 space of one centimeter. The frond is 37 centimeters in length, with about 

 15 pinnae on each side. The pinnse are from 9 to 11 centimeters long, and 

 nearly 2 centimeters wide. The lower portions of many of the pinna3 are 

 obscured in the specimen, but several show the basal structure, but too 

 obscurely to be well represented in the figure. 



In fig. 1 the nervules are not sufficiently fine and close. Fig. la shows 

 the nervation magnified. 



Location same as the last. 



Orthogoniopteeis GriLBERTi (sj). nov.). 



Plate 50, fig. 2. 



This species differs from the preceding by a relatively stronger rachis; 

 pinnas of thicker substance, shorter, lanceolate, more distant, more evi- 

 dently and broadly decurrent below, the upper basilar border curving to 

 and reaching the medial nerve at a greater distance above its base. The 

 medial nerve is prominent and well marked, but not so thick as in the 

 last species. The veins or nervules are finer and closer, and show less 

 tendency to curve upwards at the border, which is somewhat thickened. 



Forty-five nervules are counted' in one centimeter of the margin. 

 Having but a single fragment of this species, belonging, probably, to the 

 middle of the plant, or, perhaps, a little below it, it is impossible to judge 

 of its length, but it was evidently a large and beautiful fern. The pin- 

 nae are about 6 centimeters long and 15 millimeters broad. 



Locality same as the last. 



Alethopteris Holdeni (sp. nov.). 



Plate 51, figs. 1, 2, and 2a. 



Frond simply pinnate, large, with a very thick striate rachis one centi- 

 meter wide near its base, which is covered with a thick mass of scales. Pin- 

 nae long and narrow (4 to 7 centimeters long, and 7 millimeters broad), de- 

 current, greatly diminished in length toward the base ; sub-opposite 

 toward the top, sub-alternate toward the base ; oblique in the upper 

 part, open and nearly at right angles toward the base ; scythe-shaped, 

 lanceolate, taper-pointed, with a prominent midrib extending to apex. 

 Veins open, curving to the border, forking twice, once near the base, and 

 again about one-third of the distance from midrib to margin, thence 

 nearly parallel, reaching the margin at an angle somewhat acute. 



