HICK AND CASH: FOSSIL FLORA OF HALIFAX. 375 
As reg-ards the description of the fossil, it is a source of some 
satisfaction to us, that in no respect have we found it necessary to 
correct or modify what was first written. The additional specimens, 
so far as they are undoubtedly the same plant as the original one, 
simply reproduce, illustr-ate, and give point to the statements we 
originally made. As to the identity of the plant with Astromyelon^ 
our present judgment is, that such an identity is not yet established 
with the certainty that an adherence to scientific logic should demand. 
In the account of Myriophylloides already referred to, we wrote 
as follows : — 
" It consists of a central pith, surrounded by a number of 
sHghtly wedge-shaped masses of tissue, which are either of a fibro- 
vascular or of a wholly vascular character. Outside these masses of 
tissue or bundles, as we may term them, is a cambium ring, followed 
by a comparatively thick cortex. This is composed, in a great 
measure, of radiating plates composed of cells, with large interven- 
ing air cavities, similar to those met with in recent aquatic plants. 
The cellular plates do not anastomose, so that the air cavities are 
continuous from the central axis to the peripheral portion of the 
stem, which is composed of a few layers of somewhat rounded cells." 
The peculiarity of the cortical structures we regarded as one of 
the distinctive features of the plant, and one that had not been 
previously met with. At the same time, we noted the fact that the 
vessels of the vascular tissue were of the barred and dotted types, 
and that they appeared to be intermixed with elongated cells of a 
more fibrous character, whose walls were plain. 
In Prof. Williamson's Memoir already referred to, the identity 
of Myriophylloides and Astromyelon appears to be chiefly based upon 
a transverse section of a specimen of the latter plant, in which, what 
is very unusual, a part of the cortex is preserved. In this 
fragment of the cortex, there are a few cellular filaments, which 
certainly resemble those met with iu similar sections of Myriophylloides, 
and which may be transverse sections of radiating cellular plates. 
Speaking" of this section, Prof. Williamson says : — " The identity of 
the plant with the Myriophylloides of Cash and Hick, is shown by 
the retention of a small portion of the cortex. The innermost layer 
