MOSSES. 89 
also abounded ; while they occupied a consider- 
able space in the Oolitic vegetation. But it is in 
the Coal-measures that they seem to have attained 
their utmost size and luxuriance, sigillaria, lepido- 
dendron, etc., being now considered by competent 
botanists to be highly-developed lycopodia. Along 
with ferns, they covered the whole earth from 
Melville Island in the Arctic regions to the Ultima 
Thule of the Southern Ocean, with rank majestic 
forests of a uniform dull green hue. The 
numerous coal-seams and inflammable shale 
found in almost every part of the world, form 
but a small portion of their remains. ‘“ Between 
the time of the ancient lycopodite found in the 
flagstone of Orkney,’ says Hugh Miller, “and 
those of the existing club-moss that now scatters 
its light spores by millions over the dead and 
blackened remains of its remote predecessor, 
many creations must have intervened, and many 
a prodigy of the vegetable world appeared, 
especially in the earlier and middle periods 
Sigillaria, Favularia, Knorria, and Ulodendron, 
that have had no representatives in the floras of 
later times; and yet here, flanking the immense 
scale at both its ends, do we find plants of so 
nearly the same form and type that it demands 
a careful survey to distinguish their points of 
difference.” 
