536 ROBERT KIDSTON ON FOSSIL PLANTS 
was the most perfect, but on another the pinne were rather larger; all the 
other examples were much less. 
Though the pinnules of this fern in their tripartite segmentation show some 
points of resemblance to Scutmper’s genus 77iphyllopteris, I have placed it in 
Sphenopteris, to which it appears to be more closely related. 
It gives me much pleasure to name this species after Dr. A. GEIKIE. 
Position and Locality—From the Cement-stone group of the Calciferous 
Sandstone series, Glencartholm, Eskdale. 
Sphenopteris bifida, L. & H. 
Sphenopteris bifida, L, & H., Fossil Flora, pl. liu. 
as a Hibbert, “ Limest. of Burdiehouse,” Roy. Soc. Ed., vol. xiii. 
, Ke Miller, Test. of the Rocks, p. 423, fig. 129. 
Trichomanites bifidus, Geepp., Syst. Fil., tab. xv. fig. 11. 
Todea Lipoldi, Stur., Culm-Flovra, tab. xi. fig. 8.* 
Remarks.—This fern occurs very plentifully in Eskdale and Liddesdale. 
Among these specimens is one showing its mode of growth very beautifully. 
This specimen is nine and a half inches long, but the rachis does not appear 
to be complete at its lower extremity. 
Two inches above the apparent break the stem bifurcates. 
On the main axis, below the bifurcation, are a few very small, and what may 
be regarded as rudimentary pinne, which gradually increase in size from below 
upwards, but the largest is only two-fifths of an inch long. 
One of the main forks has been broken off about three inches above the 
bifurcation, but the other is entire. 
The portion of the broken fork is of the same size as the corresponding 
part in the perfect one, so we may reasonably presume they were originally 
equal. It would appear that this bifurcating of the main axis, a short distance 
above its base was characteristic of the Sphenopteris linearis group (to which 
group I feel inclined to refer the present species), as in several of the other 
ferns of this class I have observed the same structure.t 
The ultimate segments of the pinne consist of little more than a nerve with 
a very narrow margin of delicate cellullar tissue. 
In Linpiey and Hurron’s figure this narrow cellular margin has been 
entirely destroyed;{ and in that of Stur its state of preservation has been 
little better.§ 
* C. W. Peacu on “ Fossil Plants from the Calciferous Sandstone around Edinburgh,” Bot. Sce. 
Ed., vol, xiii. 
1 
t Mr. C, W. Peacu has shown me young fronds of S. afinis in the circinate condition, exhibiting 
very beautifully the two forks rolled up in a crozier-like manner, 
{ os. Flora, vol. i. pl. liii. 
§ Srur., Culm-Flora, tab. xi. fig. 8. 
