498 PALAEONTOLOGY OF ILLINOIS. 



branches, true roots which still lower bear a few thread-like filaments, without 

 trace of leaves or utricles. I have compared this kind of vegetation to that 

 of Sigillaria of the Coal Measures, merely, of course, for the mode of develop- 

 ment.* Remains of Stigmaria fill whole banks of fire clay of our Coal Mea- 

 sures, to a thickness of from six to fifty feet, and no remains of Sigillaria have 

 ever been found in this clay in connection with them. Prof. Schimper men- 

 tions an analogous circumstance from his observation on the Vosges sandstone 

 (Grauwacke Vosgienne), whose entire strata are also filled with remains of Stig- 

 maria, and where no Sigillaria is ever found.t Roots cannot live by themselves, 

 independent of any other kind of organs, and it is certainly impossible to ex- 

 plain the mode of vegetation, the form, the nature of the Stigmaria and its 

 action, in considering it as a root. But admitting these plants to be the float- 

 ing stems of species of Sigillaria to which they have been sometimes seen at- 

 tached, their peculiar nature and mode of vegetation becomes explainable, 

 and in circumstances where they are found in the Coal Measures, they are in 

 perfect harmony with the general vegetation of that epoch, as well as with the 

 end which they were called to achieve. As is the case especially with our float- 

 ing mosses, these floating stems of the Carboniferous epoch have the characters 

 blended in a kind of uniformity which renders them scarcely recognizable. 

 All the Stigmaria bear the same kind of cylindrical, bladdery leaves, and there- 

 fore have all, though belonging to different species, the same kind of cicatrices 

 upon their stems, viz. , a circular, double ring, with a single vascular scar in the 

 center. This peculiarity has been heretofore a problem to palaeontologists. 

 Binney has seen Stigmaria ficoides as the roots of Sigillaria reniformis, 

 Rich. Brown has seen the same Stigmaria as the roots of Sigillaria alternans. 

 Prof. Goeppert has obtained a splendid specimen of Sigillaria elongata, with 

 Stigmaria as its roots, and Prof. Schimper has the same Stigmaria at the base of 

 a fourth species of Sigillaria, and the fossil trees procured by Dr. D. D. Owen, 

 should be quoted still as a fifth species, S. Owenii, Lesqx., bearing Stigmaria 

 as its basilar appendages. This Sigillaria to which I have already alluded, has 

 its mould preserved in perfect integrity with the scars of the stems, those of its 

 base and those of the divisions called roots, fully discernible. The cicatrices 

 of the stem have no affinity with those of any other species of Sigillaria hith- 

 erto known. They are double, horizontally distant from each other one and 

 one-fourth inches, vertically three-fourths of an inch, formed of two transversly 

 oval scars, close to each other, joined at the corners by a deep line, thus resem- 

 bling in miniature a pair of spectacles. The small oval scars are about one- 

 eighth of an inch across in their broadest diameter, deeply marked into the 



*W. P. Schimper, Terrain de transition des Vosges, p. 324. 



fProf. Goppert, in his Permain, compares it to that of the Prothalliun of the mosses. 

 There is a mere analogy of division of the branches ; nothing more. 



