THE CARBONIFEROUS PERIOD. 169 
upright in the old Carboniferous swamps, were completely 
hollowed out by internal decay, till nothing but an exterior 
shell of bark was left. Often these hollow stumps became 
ultimately filled up with sediment, sometimes enclosing the 
remains of galley-worms, land-snails, or Amphibians, which 
formerly found in the cavity of the trunk a congenial home; 
and from the sandstone or shale now filling such trunks some 
of the most interesting fossils of the Coal-period have been 
obtained. ‘There is little certainty as to either the leaves or 
fruits of Svg¢//aria, and there is equally little certainty as to the 
true botanical position of these plants. By Principal Dawson 
they are regarded as being probably flowering plants allied to 
the existing “false palms” or ‘‘ Cycads ;” but the high author- 
ity of Mr Carruthers is to be quoted in support of the belief 
that they are Cryptogamic, and most nearly allied to the Club- 
mosses. 
Leaving the botanical position of S7gz//arza thus undecided, 
we find that it is now almost universally conceded that the 
fossils originally described under the name of S#gmarvia are 
the roots of Szgzl/aria, the actual connection between the two 
having been in numerous instances demonstrated in an unmis- 
takable manner. The Stgmarz@ (fig. 112) ordinarily present 
themselves in the form of long, compressed or rounded frag- 
a 
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Oe 
Mi “il — 
esl i 
} i I) belly ,, 
Ni paral : 
Ul) LU aa 
Ny Del yy Wel 
aT rere 
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Abel ey! \\\iN 
(1 
THN 
Fig. 112.—Stigmaria ficoides. Quarter natural size. Carboniferous. 
ments, the external surface ef which is covered with rounded 
pits or shallow tubercles, each of which has a little pit or de- 
pression in its centre. From each of these pits there proceeds, 
in perfect examples, a long cylindrical rootlet ; but in many 
cases these have altogether disappeared. In their internal 
structure, Stzgmarza exhibits a central pith surrounded bya 
sheath of scalariform vessels, the whole enclosed in a cellular 
envelope. The Stgmari@ are generally found ramifying in 
