60 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 
compared the spores with those from the coal. When gently crushed, 
the identity of the appearance presented by these forms from the 
coal was very striking. The triradiate markings of the latter were 
almost exactly like the flattened three radiating lines which mark 
the upper hemisphere of the macrospores of Isoétes lacustris. The 
writer therefore concluded that the forms in the coal were from a 
group of plants having affinities with the modern genus Jsoéées, and 
from this Isoétoid character he suggested the generic title of Isoétoides 
pending further investigation. 
Discussion. 
Mr. Carruruers thanked the author for the trouble he had taken 
in these investigations, the results of which were of value, although | 
he could not accept the conclusions arrived at. He remarked that 
there was no doubt as to the nature of the vegetation which formed 
the coal. The triradiate structure of the macrospores referred to 
was merely a superficial marking which threw very little light on 
the affinities of the spores. These spores had been found connected 
with leaves of Sigillaria and Lepidodendron. The coal itself had 
been a soil which supported the vegetation ; it is penetrated by the 
Stigmarie, roots of Sigidlarza and Lepidodendron, and by roots of 
other plants. In the museum, either at Huddersfield or Leeds, 
there is a stem of a Szgillarza filled with white sandstone and pene- 
trating far into the coal-bed, showing that the trees grew in the coal 
itself. Coal-seams are the remains of forests which grew upon 
swampy ground and were subsequently covered by clay. He had 
never found true wood-tissue in coal. Spores were first noticed in 
coal by Professor Morris. They abound in some places, but there is 
no reason to attribute. them to Jsoétes or to any other form of sub- 
merged vegetation. 
Prof. W. Boyp Dawxins agreed with Mr. Carruthers in differing 
from the author. He had never seen sporangia in coal, although 
macro- and microspores abounded. Coal is composed of two princi- 
pal elements, carbon proper and a fossil resin, to which the blazing 
property of coal is due. He agreed with Prof. Huxley in the view 
that the latter is mainly due to the spores; but the blazing element 
cannot be wholly attributed to them. According to the highest 
chemical authority woody tissue cannot by ordinary process of decay 
be converted into resinous matter. The carbon is derived from the 
decomposition of vegetable tissue, the resin from the secretions of 
the cell in the living plant. The Carboniferous forests grew upon 
horizontal tracts of alluvium not far above the water-line. 
Mr. EK. T. Nzwron considered this paper to be the first systematic 
attempt that had been made to ascertain the microscopic structure 
of a consecutive series of coal-beds. Certain coals were undoubtedly 
made up of macro- and microspores. He remarked that there are 
three principal kinds of layers in coal—bright, dull, and interme- 
diate. The dull layer contains dotted tissue, the intermediate 
macro- and microspores, and the bright a brown substance, usually 
without structure, but in one case within his knowledge entirely 
