36 
all students have recognized its Pteridophytic affinities and many have 
suggested a relationship with the so-called water ferns (Hydropetraceae). 
The late Professor Nathorst was the most emphatic advocate of such a 
relationship, which is based on habit and venation of the vegetative parts, 
and of sporoearps like those described above which he described from the 
Rhaetic of Sweden where they were associated with Sagenopteris undulata 
Nathorst. The writer considered the evidence sufficiently good to warrant 
referring the Potomac species to the Hydropteridae in 1911. 
The discovery of bodies that have all the megascopic features of sporo- 
carps, that cannot be referred to any other known elements in the associated 
flora, in association with foliage, which in habit, form, and venation, 
independently suggests comparisons with the existing genus Marsilea, at 
two such remote localities as Sweden and Alberta, is strong presumptive 
proof of relationship. Moreover, these two occurrences are very different 
in age, thus showing no obvious change in the sporoearps during the time 
that elapsed between the Rhaetic and near the close of the Lower Cre- 
taceous, a time interval comparable in magnitude with the time that has 
elapsed between the mid-Cretaceous and the present. If the sporoearps 
preserved their appearance unchanged during the older interval this con- 
servative feature becomes an argument of validity in comparing their latest 
occurrence with the Marsilea sporoearps of the present. The evidence 
then that Sagenopteris is related to the recent Hydropteraceae is about as 
conclusive as can be secured in the absence of structural material. The 
present species is confined to the Lower Rlairmore locality DR1. 
Since these paragraphs were written Thomas 1 has brought forward 
circumstantial evidence for associating Sagenopteris with a Jurassic order 
which he calls the Caytoniales, and considers to be an extinct order of 
primitive angiosperms. 
Sagenopteris mclearni Berry n.sp. 
Plate IV, figure 3; Plate V, figures 8, 9 
Peduncle stout, terminated by five reticulate veined, digitately 
arranged leaflets. Leaflets lanceolate or obovate in outline, sessile, from 
6 to 9 cms. in length and from 1 *5 to 3 cms. in maximum width. Divided 
into numerous rounded pinnately arranged divisions separated by acute 
sinuses. Texture sub-coriaceous. Venation prominent. A conspicuously 
double midrib persists three-fourths of the distance or all the way to the 
tip, becoming thin distad. The tip may be broadly rounded or narrowly 
extended. The laterals diverge from the midrib at acute angles, curving 
outward, abundantly anastomosing, and terminating in the entire margins. 
The base is narrowly cuneate, the lobing being most pronounced medianly 
and diminishing toward both the base and the tip. 
This new species, named in honour of the collector, is distinguished 
from all other known species of Sagenopteris by its invariably pinnatifid 
character. Some of the previously described species have irregular mar- 
gins, and if I had but a single specimen it might seem proper to refer it to 
Sagenopteris elliptica as an abnormal variety since the latter species is 
abundant in the Lower Blairmore. As it is I have one specimen of the 
new species from locality DF1, another from CH6, twelve from CS2, and 
40 from CH7. Moreover, the venation is coarser than in S. elliptica. 
1 Thomas, H. H.: Phil. Trans. Roy. Soe. London, ser. B., vol. 213, pp. 299-363 (1925) , 
