424 THE CARBONIFEROUS SYSTEM. 



Calamodendron. From the abundance of coniferous trees in sandstones 

 above and below the coal, and their comparative absence in the coal 

 and coal-shales, it may be inferred that these trees belonged rather to 

 the uplands than to the coal-swamps ; and the great durability and 

 small specific gravity of coniferous wood would allow it to be drifted, 

 either by rivers or ocean-currents, to very great distances. I am not 

 aware that the fruits of pine-trees occur, unless some of those called 

 Trigonocarpa are of this character. Nor has any foliage of these trees 

 been found, except at Tatamagouche, in the continuation of the Upper 

 Coal formation, where I have found leafy branchlets which I have 

 named Araucarites gracilis, and which may possibly have belonged 

 to Dadoxylon mater iarium. 



The casts or pith-cylinders known as Sternhergice are abundant in 

 some of the sandstones, especially in the Upper Coal formation. I 

 have shown that in Nova Scotia, as in England, some of these singular 

 casts belong to Dadoxylon ;* but as the pith-cylinder of Sigillaria and of 

 Lepidophloios was of a similar character, those which are destitute of 

 woody investment cannot be determined with certainty, though in 

 general the transverse markings are more distant in the Sternhergice 

 of Sigillaria and LejndopJdoios than in those of Dadoxylon. 



In a paper communicated to the Geological Society of London in 

 1846, to which Professor Williamson, in his able Memoir in the Man- 

 chester Transactions (vol. ix., 1851), assigns the credit of first sug- 

 gesting that connexion between these curious fossils and the conifers 

 which he has so successfully worked out, I stated my belief that those 

 specimens of Sternbei'gias which occur with only thin smooth coatings 

 of coal might have belonged to rush-like endogens ; while those to 

 which fragments of fossil wood were attached presented structures 

 resembling those of conifers. These last were not, however, so well 

 preserved as to justify me in speaking very positively as to their 

 coniferous affinities. They were also comparatively rare ; and I was 

 unable to understand how casts of the pith of conifers could assume 

 the appearance of the naked or thinly coated Sternbergite. Additional 

 specimens, affording well-preserved coniferous tissue, have removed 

 these doubts, and, in connexion with others in a less perfect state of 

 preservation, have enabled me more fully to comprehend tlie homologies 

 of this curious structure, and the manner in which specimens of it have 

 been preserved independently of the wood. 



My most perfect specimen is one from the coal-field of Pictou-f- 



* Proceedings of the American Association, 1837, Canadian Naturalist, vol. ii. Paper 

 on Structures of Coal, Quart. Journ. Geol. Soc. 1860. 

 f Presented to me by ]Mr Hogg of Pictou Island. 



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