260 Proceedings of the Royal Physical Society. 
Remarks.—The general aspect of Sphenopteris Dunsit 
reminds one much of certain Cheilanthes in its small 
pinnules and graceful form. 
At Plate IV., Fig. 2, is shown the most perfect specimen 
I have yet met with as far as exhibiting the details of the 
pinnule cutting. Plate IV., Fig. 1, gives a better idea of the 
growth of the fern, and is probably from near the centre of 
the frond, while Fig. 2 evidently represents a portion from 
near the base. 
The very small oval pinnules are closely placed together 
and generally overlap each other. They seem to have:been 
of delicate texture, and little able to resist decomposition. 
When decayed, their remains unite to form a dense black 
stain on the matrix, which only shows the general outline of 
the pinne. This is the condition in which the plant mostly 
occurs, and is shown at Fig. 1. If we were to judge from this 
figure, it would probably be concluded that the pinnules were 
much larger than they are, and bore several lobes. Fig. 2, 
however, shows that the pinnules are oval and very small, 
about 1 mm. long, simple on the upper portions of the 
ultimate pinnz as seen at Fig. 3, which is magnified eight 
times. At the base of the ultimate pinne they are lobed or 
dentate, as seen at Fig. 4, which is also enlarged eight times. 
The nervation is not distinctly shown, but what has been 
preserved is represented in the enlargements. 
Sphenopteris Dunst is not common, and even the few 
specimens I have met with are seldom well preserved. 
Those figured here are the two best I have yet seen. 
It gives me pleasure to name this fossil after Professor 
Duns, of the New College, Edinburgh. 
The specimen figured on Plate IV., Fig. 2, I received some 
years ago from the late Mr D. Grieve. 
Horizon.—Cement Stone Group of the Calciferous Sand- 
stone Series. 
Localities.—Colinton (the late Mr D. Grieve}, West Her- 
mand (the late Mr C. W. Peach), and Burdiehouse, near 
Edinburgh, Midlothian. 
