and Affinities o/Sigillaria, Calamites, *mdCalamodendron. 385 



axis of a plant of this genus, from the Coal-field of Nova Scotia, was 

 described as having a transversely laminated pith of the Sternbergia 

 type, a cylinder of woody tissue, scalariform internally and reticu- 

 lated or discigerous externally, the tissues much resembling those 

 of Cycads. Medullary rays were apparent in this cylinder ; and it 

 was traversed by obliquely radiating bundles of scalariform vessels 

 or fibres proceeding to the leaves. Other specimens were adduced 

 to show that the species having this kind of axis had a thick outer 

 bark of elongated or prosenchymatous cells. The author stated 

 that Prof. Williamson had enabled him to examine stems found in 

 the Lancashire Coal-field, of the type of Binney's Sigillaria vascu- 

 laris, which differed in some important points of structure from his 

 specimens, and that another specimen, externally marked like 

 Sigillaria, had been shown by Mr. Carruthers to be more akin to 

 Lepidodenclron in structure. These specimens, as well as the Sigil- 

 laria elegans illustrated by Brongniart, probably represented other 

 types of Sigillarioid trees ; and it is not improbable that the genus 8i- 

 gillaria, as usually understood, really includes several distinct generic 

 forms. The author had recognized six generic forms in a previous 

 paper and in his "Acadian Geology ;" but the type described in the 

 present paper was that which appeared to predominate in the fossil 

 Sigillarian forests of Nova Scotia, and also in the mineral charcoal of 

 the coal-beds. This was illustrated by descriptions of structures oc- 

 curring in erect and prostrate Sigillarice, on the surface of Sternbergia- 

 casts, and in the coal itself. 



The erect Calamites of the coal formation of Nova Scotia illus- 

 trate in a remarkable manner the exterior surface of the stems of 

 these plants, their foliage, their rhizomata, their roots, and their 

 habit of growth. Their affinities were evidently with Equisetaceae, 

 as Brongniart and others had maintained, and as Carruthers and 

 Schimper had recently illustrated. The internal structure of these 

 plants, as shown by some specimens collected by Mr. Butterworth, of 

 Manchester, and soon to be published by Prof. Williamson, showed 

 that the stems were more advanced in structure than those of mo- 

 dern Equiseta, and enabled the author to explain the various ap- 

 pearances presented by these plants when the external surface is 

 preserved, wholly or in part, and when a cast of the internal cavity 

 alone remains. It was further shown that the leaves of the ordinary 

 Calamites are linear, angular, and transversely wrinkled, and differ- 

 ent from those of the Asterophyllites properly so caired, though some 

 species, as A. comosus, Lindley, are leaves of Calamines. 



The Calamodendra, as described by Cotta, Bijtney, and others, 

 and further illustrated by specimens from Nova Scotia and by 

 several interesting and undescribed forms in the collection of Prof. 

 Williamson, are similar in general plan of structure to the Cala- 

 mites, but j, much more woody plants — and if allied to Equisetacese, 

 are greatly more advanced in the structure of the stem than the mo- 

 dern representatives of that order. Specimens in the collection of 

 Prof. Williamson show forms intermediate between Calamites and 



