21 



(6) SIGILLARTA (Favularia ?) 



This example was furnished by another erect tree, about 

 a foot in diameter, and which I took down with care and 

 examined its contents. It was described and figured in the 

 journal of the Geological Society of London. 1 Jt presented 

 the following parts: 



(a.) A coaly outer bark, no doubt originally composed 

 of dense sclerenchyma. 



(6.) A cylinder of sandstone, representing the inner bark 

 entirely removed by decay. 



(c.) A ligneous axis composed of wood cells, the inner 

 with two rows of contiguous bordered pores on their radial 

 surfaces, the outer with only one. The medullary rays 

 short, frequent, and of one row of cells or sometimes partly 

 with two rows. Diagonal bundles of pseudo-scalariform 

 tissue traversed this cylinder, no doubt leading to the 

 leaves. 



(<?.) An inner cylinder of pseudo-scalariform tissue 

 similar to that in the inner cylinder of the axis in Cordaites 

 and in Cycads. 



(0.) A medulla or pith, consisting of a hollow cylinder of 

 cellular tissue sending off at intervals thin diaphragms 

 toward the interior, giving it a Sternbergia structure. 



This type of Sigillarian stem is obviously of far higher 

 grade than the former, and would justify the inference that 

 it belonged to a gymnospermous plant. The structures of the 

 stem correspond with that of others in which the axis exists 

 only as fragments in the base of the once hollow stump. 

 Some of these, however, conform to the type of multiporous 

 wood-cell seen in Poroxylon. If the foliage was like that 

 of Sigillaria elegans, and the spikes of fructification of the 

 nature of Antholithes, these parts might be referred to Oor- 

 daitece, though the stem was ribbed in the manner of 

 Sigillaria. I may add here that I have shown 2 that some 

 Sigillarm of the Favularia type, divided at top into small 



1 Vols. xxvi. and xxvii., 1870 and 1871. 



2 Journal Geological Society, Vol. xxii., also Acadian Geology. 



