1862.] BrNNET SIGILLARIA AND LEPIDODENDRON. 107 



hexagonal vessels (b) of much less size, arranged in radiating series 

 of a wedge-shape, and divided by medullary rays of finely barred 

 vessels, as Stigmaria and Sigillaria. Outside this series are some 

 circular bundles of small vascular tissue, similar to those described 

 by Brongniart in Sigillaria elegans. Next comes a mass of delicate 

 cellular tissue {d), which has generally been destroyed, and replaced 

 by mineral matter. This is succeeded by a zone of coarse cellular 

 tissue (/), which gradually passes into the outer circle, composed of 

 small hexagonal utricles {g), arranged in radiating series ; and then 

 comes some coarse cellular tissue, which appears to have been the 

 outer bark (A). 



The fossils were found by me in the lower part of the Lanca- 

 shire coal-measures, as were also the specimens of Trigonocarpon 

 described by Dr. Hooker and myself in the ' Philosophical Transac- 

 tions '* for 1855, but in a different seam of coal. They occur in cal- 

 careous nodules of various shapes, dispersed throughout the seam, and 

 evidently afford a fair sample of the vegetable matter of which such 

 coal was formed ; they having been calcified, and thus preserved, 

 before the bituminizing process commenced, which ultimately con- 

 verted the rest of the vegetable matter surrounding them into coal. 

 The seam varies from 2 to 5 feet in thickness. It has a good floor, 

 full o{ Stigmaria ; and its roof, a black shale containing rounded and 

 depressed nodules of calcareous and ferruginous matters, abounds with 

 remains of Aviculopecten papyraceus, Ooniatites Listeri, Nautilus, 

 Bellerophon, and other marine shells, the destruction of which has 

 most probably afforded materials for the calcification of the nodules 

 found in the seam of coal. Although fossil shells occur abundantly in 

 the nodules found in the roof of the coal, they have not as yet been 

 met with near the locality where the specimens were met with in 

 the nodules containing the fossil wood amidst the coal itself t- 



The Lepidodendron is the most common plant in the coal found 

 preserved in the nodules, although specimens of LejDidostrobus, Halo- 

 nia, Sigillaria, Stigmaria, Anahathra, Calamites, Lycopodites, and 

 other plants, all more or less showing structure, are frequently met 

 with. 



In the present paper it is my intention to confine myself to the 

 description of three specimens of fossil plants which would generally 

 have been designated Lepidodendron in England, and Sagenaria on 

 the Continent. 



No. 1. The specimen illustrated in PI. lY. consists of a cylindrical 

 stem ^ths of an inch in diameter, nearly enveloped in its stony 

 matrix, and only showing its external characters on one side. These 

 consist of rhomboidai scars, of an elongated and somewhat irregular 

 form, arranged in quincuncial order, but not so perfectly as seen in 

 most species of Lepidodendron. In the middle of each scar there is 

 an oval depression, from which rises a rounded prominence where 

 the leaf was attached. These scars resemble those of Lepidodendron 



* Vol. cxlv. p. 149, &c. 



t I have in some few instances found nodules in the coal it.3elf containing 

 shells, but these are rare. 



