136 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jan. 21, 



EXPLANATION OF PLATE VIIL 



Fig. 1. Coprolite from the carboniferous sandstone of Nova Scotia. 



2. Fossil trunk in situ having roots resembling Stigmaria (Malagash). 



1. Dark grey shale with fern leaves. 



2. Ditto coarse shale. 



3. Hardened dark-coloured clay. 



4. Limestone. 



a. Attached roots. 

 6. Roots not attached. 



c. Bark. 



d. Ligneous surface. 



e. Core and attached fibres. 



3. Stigmaria with rootlets penetrating sandstone and shale (Malagash). 



1. Shale. 



2. Sandstone. 



4. Sternbergia from the Pictou coal-field, and recent Juncus effusus with 



part of the pith uncovered. 



a. Stony cast of pith. 



b. Coat of lignite. 



4f. Notes on the Fossil Plants communicated by Mr. Dawson from 

 Nova Scotia. By C. J. F. Bunbury, Esq., F.G.S. 



The observations of Mr. Dawson on the fossil roots having the cha- 

 racters of Stigmaria are curious and important, as corroborating the 

 statement communicated by Mr. Binney to the British Association 

 in June 1845, respecting the tree with similarly marked roots which 

 was discovered at St. Helens in Lancashire. Mr. Binney 's state- 

 ment, clear and positive as it seemed, has nevertheless been doubted 

 by some of our most eminent geologists, who have believed the 

 connexion of the supposed stem and roots to be merely apparent or 

 accidental ; and it is possible that similar doubts may be thrown on 

 Mr. Dawson's observations. He appears however to have satisfied 

 himself, that one of the Stigmaria-like specimens now before us did 

 actually proceed in the manner of a root from the base of the stem. 

 These specimens differ in some degree from the best- characterized 

 forms of Stigmaria, their scars not having the distinctly circular and 

 umbilicated form that is usual in that fossil : the appearance is as 

 if the leaves or rootlets (whichever they may be) had not been dis- 

 articulated, but broken off abruptly ; yet the symmetrical quincun- 

 cial arrangement of these scars, the presence of the excentric axis, 

 and the general appearance of the fossils, leave no doubt that they 

 are referable to the supposed genus Stigmaria. It has been urged, 

 that the symmetrical arrangement of the scars is a fatal objection 

 to the idea that these bodies were roots, which never emit their 

 fibres with any degree of regularity ; but, unless we suppose that 

 Mr. Dawson has been deceived by appearances, this argument, 

 drawn from the analogy of existing plants, must yield to the positive 

 result of observation. It would not be the first instance in which 

 the progress of discovery has revealed striking exceptions to what 

 had been supposed general laws of structure. Exact and multiplied 

 observations are certainly necessary to establish the existence of 



