248 Messrs. E. W. Binney and R. Harkness's Account of 



theroots proceeded downwards, they increased in width, and 

 the spaces became narrower in consequence, until the roots 

 again rapidly narrowed and finally terminated. The secon- 

 dary roots also gave rise to secondary spaces; these com- 

 menced about one foot three inches below the upper part of 

 the principal spaces; they were likewise rounded at their 

 upper extremities, but continued to increase in width as they 

 descended. These spaces were separated from each other by 

 the thickness of the secondary roots, which measured two feet 

 four inches. At the distance of about seven inches below the 

 higher extremities of these secondary spaces, originated the 

 spaces caused by the bifurcation of the tertiary roots; these 

 were separated from each other at their origin by one foot four 

 inches, the breadth of the tertiary roots. In form these spaces 

 resembled those produced by the secondary roots, except in- 

 creasing more rapidly in width as they descended. This uni- 

 formity and regularity in the roots of this plant will be more 

 manifest by referring to Plate VI., which would represent the 

 roots if compressed ; where A shows the main roots. A' the 

 principal areas, B the secondary roots, and B' the secondary 

 areas, C the tertiary roots, and C' the tertiary areas. This pe- 

 culiar regular mode of rooting is most probably characteristic 

 of this genus of plants, and the various degrees of dichotomi- 

 zation appear to result from a difference of age in the different 

 individuals. Thus, in the small specimen found about five 

 feet east of the large one, there is seen only the four main 

 roots, which had not commenced bifurcating at their base. 



In the trees found at Dixon Fold, the same regular appear- 

 ances are presented as in the large individual; and a Stigma- 

 ria in the museum of the Leeds JPhilosophical Society affords 

 evidence of a similar regularity. 



Such is the description of a tree having for its base and 

 roots a fossil the most common in the coal formation, and 

 concerning which various incorrect opinions have been pro- 

 pagated, resulting in part from an examination of imperfect 

 specimens, and also from authors refusing to receive correct 

 descriptions, which did not altogether coincide with their pre- 

 conceived itieas of the natural affinities of this fossil. Stig- 

 maria has, since the commencement of geology as a science, 

 never ceased to exercise the ingenuity of fossil botanists; but 

 of all the accounts we possess concerning this fossil, the one 

 published in the year 1818 in the Transactions of the Ame- 

 rican Philosophical Society stands pre-eminent, both for its 

 fullness and its remarkable accuracy ; and although some of 

 the deductions are incorrect, still the great care and correct- 

 ness of Mr. Steinhauer, as manifest in this account, cannot be 



