PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 61 
composed of spores, and Mr. Wethered had found this same brown 
substance formed by vegetable tissue. 
Prof. T. Rupert Jones inquired of Prof. Boyd Dawkins how 
Conifers were to be traced in coal if not by structure. He thought 
that the spores would themselves supply the resinous or hydro- 
carbonaceous matter. ; 
Mr. Baveruan commented on the value of the author’s diagrams 
as showing very clearly the freedom of coal substance from mineral 
matter when the partings were separated. As regarded the latter, 
was there any distinction, asin the proportion of alkalies &c., between 
them and the under-clays? While agreeing with the author as to 
the unfitness of the term bituminous (as coals contained no consti- 
tuent removable by the reagents in which natural bitumens were 
soluble), he thought the term hydrocarbon was no improvement. 
To him both the tissues and the structureless parts of the author’s 
sections seemed te be of the same nature, namely, pseudomorphs in 
coal-substance. Crystalline hydrocarbons (paraffines) had been ob- 
tained by Mr. Thomas from the gases of some coals under conditions 
which seemed to indicate their existence as such in the coal; and if 
such substances were present they should be recognizable. As plants 
are made up of materials varying very considerably in their resis- 
tance to decomposition, and as only the more stable ones were likely 
to retain their structure, the fact of such structures as those of 
spores being recognized in microscopic sections seems to be no proof 
that whole seams were made up of them. 
Mr. Krpsron considered that there was no doubt that coal was 
a product of terrestrial vegetation, but said that it was doubtful if 
Conifers really occur in coal. Sporangia are abundant in parts ; 
but he had found that they were rare in Scotch coal. 
Mr. CarrutHERs, in explanation, said, that the macrospores were 
not originally composed of brown substance, but merely filled 
with it. 
The Aurnor, in reply, said, Stigmarie might be roots of plants 
allied to Isoétes. Lepidodendron and Sigillaria were regarded as 
allied to the existing Lycopodia, as also was Jsoétes, so that there was 
no reason why an Isoétoid plant should not have Stgmaria-roots, 
and Isoétes is the only existing plant of the group in which the 
macrospores show triradiate structure. His conclusions were entirely 
based on the evidence of the microscope. He remarked that Prof. 
Boyd Dawkins had formerly adhered to the views of Prof. Huxley, 
so that he must now have materially changed his opinion. In reply 
to Mr. Bauerman he said that some partings were very similar 
to under-clay, and that decomposed vegetable tissue could not well 
be crystalline. To Mr. Kidston he said that if sections were made 
thin enough, spores would probably be found even in some Scotch 
coals. 
2. “On Strain in connexion with Crystallization and the Deve- 
lopment of Perlitic Structure.” By Frank Rutley, Esq., F.G.S. 
