SIGILLARIA. 



99 



those irregularly ribbed and furrowed stems described by me under the name Sigillaria 

 vascularis, sometimes attaining seven feet in diameter. In the fossil forests of trees 

 standing erect in the Coal-measures, which have come under my observation, nearly all 

 belong to the last-named genus. In thePeraberton Hill Cutting, on the railway between 

 Wigan and Liverpool, six out of thirty stems, from one to two feet in diameter, exhibited 

 the scars of Sigillaria reniformis, 8. alternans, and S. organum ; the remaining twenty- 

 four belonging to 8. vascularis. On the numerous fossil trees found in cutting the 

 Clay-Cross tunnel, on the Midland Railway, near Chesterfield ; in the specimens found 

 in the deep pit at Pendleton, some of which were more than fifty feet in height ; in that 

 from the Victoria pit, Dukinfield, now in the Manchester Museum ; in those on the 

 Manchester and Bolton Railway, at Dixon Pold, described by Messrs. Hawkshaw and 

 Eowman ; and in the large steins from the Trap-Ash, of Laggan Bay, discovered by 

 Mr. Wiinsch ; there was no evidence of distinct leaf-scars, but only irregular ribs 

 and farrows. All the specimens except the last named were seen and examined by 

 me in situ. The only example of a very large Sigillaria showing distinct leaf-scars, 

 which has come under my observation, is specimen " No. 49 of Sigillaria reniformis, 

 now in the Museum of the School of Mines in Jermyn Street. Unfortunately, all the 

 above-mentioned specimens, except those from Laggan Bay, afibrd no traces of internal 

 structure. These last, however, some of which are about two feet in diameter, afford 

 evidence of the structure of the thick inner bark, termed by me the outer radiating 

 cylinder, and the woody or inner radiating cylinder of barred tubes, containing vascular 

 bundles and medullary rays, enclosing a medulla, composed of barred tubes, in all respects 

 exactly similar in structure to the large Sigillaria vascularis, with irregular ribs and 

 furrows, described by me in the ' Philosophical Transactions -'^ and the smaller specimens, 

 exhibiting on their outsides scars of Lepidodendron, described in the ' Quarterly Journal 

 of the Geological Society.'" These large and small specimens gradually pass one into 

 the other, as numerous specimens in my cabinet, in addition to those figured, amply 

 testify. Many persons have become accustomed to class my small specimens, the first 

 ever described showing a medulla of vascular tubes, as Lejjidodendra, from their 

 external characters, without regarding their inner radiating cylinder and its singular 

 medulla, so totally different in arrangement to the vascular cylinder and medulla of 

 orthosenchymatous tissue of LejAdodendrou Ilarcourtii before described in this 

 Monograph. 



When M. Brongniart described the structure of Sigillaria elegans he had before him, 

 and described in the same Memoir as perfect specimens of Lejndodendron and Stigmaria, 

 with the exception of the medulla and outer radiating cylinder, as have been met with 

 up to this time ; and he alludes to the probability of Stigmaria being the root of 

 Sigillaria ; but he notices the remarkable diffierence in structure between Sigillaria and 

 Lepidoden dron . 



' For 18G5, p. 579 et seq. ■ Vol. xviii, 1862, p. 111. 



