374 HICK AND CASH: FOSSIL FLORA OF HALIFAX. 
Additional well-preserved specimens will be required to confirm 
the homologies here sugg-ested, before they can be accepted without 
reservation ; but it may be pointed out that the undoubted affinities 
of Calamites with Equisetum are all in their favour. Should they be 
eventually fully established, what we have described as the inner 
cortical layer, will have to be regarded as phloem belonging to the 
vascular bundles. The cortex will then consist of the tissues des- 
cribed as making up the middle and outer cortical layers, and will be 
brought into a closer agreement with the cortex of Equisetum. 
We append the following particulars respecting the dimensions 
of the specimen : 
Total diameter =0*2 inch, nearly. 
Longer diameter of pith = 0'091 inch. 
Breadth of vascular zone = 0 0175 inch. 
Breadth of cortex = 0*0315 inch. 
Large elements of inner cortical layer = 0-00425 x "0003. 
Myriophy lloid es Williamsoni. 
In the vol. YII., p. 400 of the Transactions of this Society, we 
published a detailed description of a remarkable fossil stem or branch, 
for which we proposed the name of Myriophylloides Williamsoni. 
Our description created no little interest amongst the few investi- 
gators who are working at palseophytology, and additional examples 
of the fossil were soon brought to light by the praiseworthy efforts 
of Messrs. Binns and Spencer. Mr. Spencer's specimens led him 
to the conclusion that our Myriophylloides was the early corticated 
condition of a plant previously described as Astromyelon ; and Prof. 
Williamson having gone over the whole series of specimens, both 
new and old, has adopted Mr. Spencer's view. The grounds on 
which he has done so, are fully set forth in part XII. of his memoirs : 
" On the organization of the Fossil Plants of the Coal Measures," 
which contains also descriptions and figures of the more demonstra- 
tive specimens. This most interesting and valuable contribution to 
our knowledg'e of fossil plants, we have studied with great care, and 
by the light of the new facts it contains, have gone over again our 
original description of Myriophylloides. It is due both to ourselves 
and to the members of this Society, that we should state, as briefly 
as possible, the position in which we find ourselves. 
