DESGEIPTION OF SPECIES. 65 



differs from that of all other species of Pterophyllum of this type, for they 

 are suddenly narrowed at the extremities and have an oblong form. The 

 branching of the nerves at their insertion is another peculiar feature. The 

 obliquity of the insertion of the outside nerves, and the perpendicular posi- 

 tion of the central ones of the lower leaflets, are features seen in the nerva- 

 tion of Ctetiophyllum Braunianum, and also in the Pterophyllum cequale of 

 Nathorst, as given by him in his "Floran vid Bjuf," plate xv, fig. 6 a; indeed, 

 the Virginia plant, notwithstanding the contradiction in the names, is strik- 

 ingly like this plant from the Rhaetic of Sweden. Fig. 1 1 of this plate gives 

 a representation of the plant which is very much like the Virginia fossil. 

 We find in the Swedish plant the same shape and size of the leaflets; they 

 terminate in the same blunt extremities, and the nervation is the same. The 

 midrib of the Swedish plant has also a raised line, or cord, in the middle. 

 The leaflets given by Nathorst are more uniform in width than those of the 

 Virginia plant, but some of the specimens have narrow leaflets, and others 

 wider ones, just like those of the Virginia fossil, however, they are on distinct 

 fragments in the Swedish Pterophyllum. Another fossil which is very near 

 the Virginia plant now in question is Pterophyllum longifolium, Andrae, from 

 the lower Lias of Steirdorf. It shows the same peculiarity of having narrow 

 and wide leaflets intermingled. Pterophyllum longifolium, which is Schimper's 

 P. Jageri of the Trias, Emmons's Pterozamites decussatus, Andrae's plant, and 

 the Virginia fossil, P. incequale, all seem to be closely allied, and perhaps 

 are the same species, modified only by differences of geological age and of 

 locality. 



Our plant is, as above intimated, a good deal like Pterophyllum longi- 

 folium, Brongt., as described by Heer in his "Pflanzen der Trias," and fig- 

 ured on plate xxxiii, fig. 1. Heer's plant, however, has a very different 

 termination for the leaf; the leaflets are regularly of the same width, the 

 nervation is all perpendicular to the midrib, and the nerves are not branched 

 at their insertion. 



The Virginia plant has some resemblance to Emmons's Pterozamites 

 decussatus, "Am. Greol.," plate 3, fig. 1. 



Formation and locality. — Found only in two specimens, both on the same 



slab, at Clover Hill, in strata associated with the upper series of small 



coal seams. 

 5f 



