338 ON LEPIDODENDRON AND CALAMITES. 
establishment of which was absolutely necessary in the earlier days of 
paleontological botany. Thus, to give an example :—the trees be- | 
longing to the same set as those which were found imbedded in the 
sal dede at Craigleith quarries have been constituted into the genus 
Dadoxyion ; the pith forms the genus Sternéergia, and some fluted and 
constricted specimens have been referred to Calamites. The leaves 
were considered to be ferns, and named Cyclopteris ; and the fruit was 
thought to belong to a Palm, and received the name of Trigonocarpon. 
We have not seen evidence sufficient to convince us that all these are 
correetly referred to the same plant; but this is the opinion of some 
distinguished paleontologists, and it serves as a good illustration of 
the present satisfactory tendency of paleontological botany. 
A similar multiplication of generic names encumbers the synonymy 
of the two genera Lepidodendron and Calamites. 
Lepidodendron was a branching tree of considerable size. It is 
separated from the other genera of coal plants by the form and 
arrangement of the leaf-scars upon its stem. More than forty species 
have been recorded; but as the scars present different appearances on 
different portions of the same plant, no doubt more species have been 
established than the materials fairly warrant. But that they were 
numerous in species, and very numerous in individuals, any one who 
has even cursorily examined a coal-pit, or the fossils in any public 
museum, must be convinced. They certainly contributed largely to 
the formation of coal. 
The researches of Witham,* Lindley and Hutton, Brongniart and 
Binney,§ have made us acquainted with the stem. These published 
* ©The Internal Structure of Fossil bps mega 1833. 
+ ‘The Foss Flora of Great Be itain,’ 1831— 
t ‘Observations sur la Structure serene P Sigillaria elegans, ete.’— 
Archives du Muséum, 
§ ‘ Geologic Society’ s, J ournal,’ dis and ‘ Philosophical Transactions,’ 
careful 
1865. Mr these rs, gives most careful and elab drawin 
ons of some fossils in his pond collecti: He refers them to 
the genus Sigil use of their agreement in internal structure 
ro 's S. elegans ; but he cannot separate them by their external mark- 
ings from L n selaginoides, Lindl. a tt.; and as the only c 
racters by which the two genera are distinguished are derived from the mark- 
ings on the stem, we must c er Sigillaria v as a true Lepidoden- 
more satisfied as to this, because I believe no essential differ- 
ence exists, as E aintained, between the stems of Sigillaria 
it m n 
or any of the other lepidodendroid plants of the coal peri " 
I cannot enter into -= question here, but I shall take an early opportunity © 
publishing m; reasons intaining them. 
