72 'Die American Geologist. February, i8W 
revealed plant tissues in them, there is close agreement; and 
the yellowish resin-like "body'' of the plants is present in 
each, and carries with it sufficient evidence to make it plain 
that this particular vegetation was hydrocarbon-producing. 
It is well known that leaves of certain plants yield a great 
deal of oil. Pines and conifers produce vast quantities of 
resins and gelose material. The coal-plant macrospores, mi- 
crospores and (?) pollen are said to be convertible into min- 
eral resin. Sea weeds and other aquatic plants yield residual 
products of tarry and oily nature capable, under favorable 
conditions, of becoming chemically coal-like solids.* We 
may be quite safe in assuming that the breaking-down or de- 
composition of much of the more woody parts of the coal- 
period vegetation was productive of a vast quantity of fluid 
resinous materials that found their way into the areas of coal 
accumulation, and there materially helped to make coal. 
Where are the remains of the aquatic or algous vegetations 
of the coal-period if not in the beds of coal? Perhaps — prob- 
ably even — there were then more water plants than land plants. 
That there was a terrestrial flora is certain; that there was 
then more water than land is highly probable. That land 
plants were evolved from aquatic forms is not unlikely. There- 
fore we cannot ignore the supposed existence of a goodly 
number of w^ater-plants as well as marsh- or swamp-loving 
.species, in the coal-age. Thus there were probably several 
sources of this resin-like, cementing material operating* as de- 
position proceeded. 
3. Quite an appreciable quantity of the material of many 
beds of coal in North America consists of rod-like bodies 
(whole or in fragmentary state) about 1-50 of an inch in di- 
ameter. For the most part these rods consist of compact, 
shiny black, brittle, solidified hydrocarbon. Some are com- 
posed of fibres, some of plates; but most of them seem to be 
structureless. Occasionally the black substance gives place 
to semi-transparent materials of various shades of yellow, 
while rods of a milk-white substance are still rarer. These 
yellow and white substances are sometimes present in rods 
o{ coaly composition, in the form of spindle-shaped masses, 
disposed in single rows of disconnected beads running through 
*See works of Sterrv Hunt and Bischof, 
