SIGILLARIA. 46^ 
Sigillaria. 
Besides the above plants of the Coal formation 
which 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 Calami tes 
take their place in the existing family of Equi- 
setacese ; that many fossil Ferns are referrible 
to living genera of this extensive family ; and 
that Lepidodendra approximate to living Lyco- 
podiaceae and Coniferse. Together with these, 
there occur other groups of Plants unknown in 
modern 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. 
Brongniart 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 
itself, to the substance of which they have 
largely contributed by their remains. They 
are sometimes seen in an erect position, where 
views of the strata are afforded by cliffs on the 
* PL 5Q, Figs. 1. 2. 
