1908] FenhuU<)H\ Fossil Plants from Milicaukee, Wisconsin. 9 
These dimensions, however, probablv do not represent the real 
base of the plant, since there is no evidence of a root svstem or of 
holdfasts. There is no evidence of branching at any part of the 
stem, although on the central fragment, on the side opposite that 
shov^n in the photograph, there is an apparent knot suggestive of a 
projecting organ of some sort. On closer examination, however, 
it is seen, that this feature is completely covered by a prominent 
layer of coal derived from the carbonization of the superficial 
parts of the stem. Whatever its character may be, it is, therefore, 
clearlv related to the interior structure and not to the surface 
parts. 
The specimen shows several transverse joints. These are in 
no sense structural, but have been caused by displacement in the 
matrix and were subsequently filled with silica. Such joints are 
well known features of N ematophycus. Apart from them, there 
is no evidence of nodes, from which it may be concluded that the 
stem was of a very simple character such as may be met with in 
the stipes of the Laminariae. 
The interior of the specimen has been entirely occupied by 
silica which has so completely replaced all structure that no evi- 
dence of the nature of the plant from that source could be ob- 
tained. The only basis from which information could be secured, 
was found in the general form of the specimen and the occurrence 
of a very prominent layer of coal which originally extended over 
the entire surface, but which, owing to its very friable character, 
has been very largely removed. The side of the specimen shown in 
the photograph, indicates the almost complete removal of this 
layer, but on the opposite side it covers nearly half the specimen. 
The coaly layer has a maximum thickness of 2 mm., and gives 
abundant evidence of the former presence of plant structure. 
In endeavoring to determine the possible nature of the plant 
represented, it may be recalled that there are only two genera of 
