locality (4,5). The present form is the sixth. The floral 
evidence substantiates the Lower Devonian age reference 
based on the primitive fishes. 
The plant fossils, as well as the best preserved fish re¬ 
mains, occur in a massive, mouse-gray, argillaceous lime¬ 
stone, weathering to grayish and pinkish buff. These 
beds are well exposed in the eastern scarp face of Bear- 
tooth Butte between thirty and ninety feet above the 
base of the deposit. 
Botanical considerations 
Sphondylophyton hyenioides apparently was a loose- 
i ly tufted plant growing in a frequently flooded habitat. 
It is probable that all of the disconnected axes preserved 
on specimen No. 24101 (Fig. I) belong to the same 
plant. Their appearance suggests that they might have 
arisen from a single basal portion and were more or less 
flattened out eentrifugally in several directions before or 
during preservation. They may have rotted off and fallen 
? into the wet mud at the exact place of growth. Since no 
fragments of the axes of Sphondylophyton hyenioides have 
| been found on any other specimens collected from the 
| fossiliferous horizon, it argues that the fragments asso¬ 
ciated so closely together on specimen No. 24101 did not 
float in from some other location, but were probably at¬ 
tached to the same base and were preserved essentially in 
place. 
The axes appear to be unbranched, and, although the 
length of the shoots may have been somewhat longer 
than in the fossil, it is probably true that sufficient 
lengths are preserved to warrant the statement that the 
plant did not branch above the base. It is certain from 
the specimen that branching was rare if it did occur. 
The axes appear also to have been capable of standing 
more or less erect and of supporting the relatively large 
[23] 
