SIGILLARIA. 
46.') 
Sigillaria* 
Besides the above plants of the Coal formation 
tvhich are connected with existing Families or 
Genera, there occur many others which can be 
referred to no known type in the vegetable 
kingdom. We have seen that the Calamites 
take their place in the existing family of Equi- 
setaceae ; that many fossil Ferns are referrible 
to living genera of this extensive family ; and 
that Lepidodendra approximate to living Lyco- 
podiaceae and Coniferae. Together with these, 
there occur other groups of Plants unknown in 
ttiodern vegetation, and of which the duration 
Seems to have been limited to the Epochs of the 
Transition Period. Among the largest and tall- 
est of these unknown forms of Plants, we find 
'Colossal Trunks of many species, which M. Ad. 
I^rongniart has designated by the name of 
Sigillaria. These are dispersed throughout the 
Sand-stones and shales that accompany the Coal, 
and can occasionally be detected in the Coal 
dself, to the substance of which they have 
largely contributed by their remains. They 
are sometimes seen in an erect position, where 
’'^iews of the strata are aftbrded by cliffs on the 
* PI. .56, Figs. 1. 2. 
