the Fossil Trees found at St. Helenas. 251 



The interior of the large specimen did not afford any traces 

 of the small internal cylinder eccentrically situated, so common 

 to uncompressed Sigillaria; nor by fracture did it show any- 

 thing which would lead to a knowledge of its internal struc" 

 ture. Fortunately for fossil botany, a specimen of Sigillaria 

 elegans from Autun, with internal structure, fell into the hands 

 of the illustrious French botanist, Adolphe Brongniart. From 

 an examination of this individual, he was induced to refer Si- 

 gillaria to the Cycadeons gymnosperms, and the internal cy-- 

 linder which had hitherto been considered as pith, he found to 

 consist of both pith and woody fibre, separated from each other 

 by reticulated vascular tissue. Between this cylinder and the 

 cuticle there was an immense development of cellular tissue, 

 through which the bundles of vessels ran which communicated 

 with the scars on the exterior of the plant. In his observa- 

 tions on the internal structure of this fossil, this botanist enters 

 into an examination of the characters of Stigmaria, and sug- 

 gests, that in all probability it is merely the root of Sigillaria, 

 and that in its internal arrangement it bears great resemblance 

 to the roots of the Zamia pungens. With regard to the re^- 

 gular order of the areolae, which induced the authors of the 

 Fossil Flora to suppose that Stigmaria could not have been 

 roots, Brongniart states that a similar arrangement is met with 

 in the roots of some aquatic plants. 



In the year 1839, Mr. Binney, in company with several gen- 

 tlemen, found some upright specimens of Sigillaria reniformis 

 resting upon a small seam of coal exposed in cutting the tun- 

 nel at Clay Cross, on the North Midland Railway near Ches- 

 terfield. These were followed downwards until they becanie 

 Stigmaria, but there was some difficulty of proving the abso- 

 lute insertion of one plant into the other, so that in this case 

 some doubt existed. 



From the present tinie, by the discovery of the fossil tree at 

 St. Helen's, the question as to the relation which existed be^ 

 tween Sigillaria and Stigmaria must be considered as settled in 

 favour of the opinion of the one being the stem and the other 

 the root of the same plant, justifying the conclusion formed by 

 one of the authors of this account in 1839, and the inferences 

 afterwards drawn from an examination of their internal struc- 

 ture by Brongniart. 



What may have been the foliage of Sigillaria, the authors, 

 from actual observation, are not prepared to say; but they 

 consider it not improbable that Pecopteris nervosa^ from its 

 great abundance and its peculiar character, may have been in- 

 timately connected with this plant. This peculiar character 

 consists in the absence of any midrib in the leaflets, and in 



