76 



FOSSIL PLANTS. 



from the structure of its rootlet, might be supposed to be a stem (as originally entertained) 

 rather than a root, as it has undoubtedly been proved to be by actual connection of the 

 one with the other. 



When we come to examine more carefully the specimens of plants found in coal-floors, 

 it is probable that we shall find the remains of the roots of many different plants besides 

 those of Sigillaria. The greatest difficulty we have to encounter in our investigation is 

 the wretched condition in which the fossils are found, being usually very much compressed 

 and distorted ; and seldom in my own experience, except in the case of " Gannister" 

 floors, has it been possible to obtain any trace of the internal structure of the plants. 



It must always be borne in mind that the specimens of fossil woods showing structure 

 in a perfect condition are generally of a very small size ; those of Calamodendron commune, 

 and the small Stipnaria-Wke plant from the Upper Foot Coal, often being only from one 

 twentieth to one thirtieth of an inch in diameter. In such small spaces every cell of the 

 medulla, as well as those in the radiating woody cylinder, is preserved in as perfect a 

 condition as it existed in the living plant. But Sicjillaria vascularis, Lepidodendron, and 

 Halonia are seldom, in my own experience, found of less size than one third of an inch in 

 diameter, which, is a large size when compared with the minute specimens of Calamo- 

 ^dendron and 8tigmaria-Y^t plants above alluded to. 



It may be asserted with confidence that up to the present time we do not know of any 

 specimen of Lepidodendron exceeding three inches in diameter, or any specimen of Sigil- 

 laria one foot in diameter, that affords evidence of its internal structure in anything like a 

 perfect condition. 



Assuming Stigmaria and Halonia to be roots, they have this marked difference, 

 namely, the former, having attained its usual characters, is not found to bifurcate, 

 whilst the latter appears to continue to bifurcate as far as it has been possible to 

 trace it. 



Great caution is required in attempting to connect the different, though allied, fossil 

 plants by a series of gradations from one to another, taking a little from each, and then 

 joining those parts together, more especially if the describer be an accomplished draughts- 

 man ; for his pencil is often too apt to be directed by his preconceived ideas rather than by 

 the simple and true delineation of the specimen itself, I have endeavoured, as much 

 as possible, to represent truly the appearance of the structures as seen in the specimens ; 

 and in order to do that I have had the advantage of securing the services of so correct 

 an artist as Mr. J. N. Fitch, who gives exact delineations of the specimens as they appear 

 to his unbiassed eyes, and not according to any preconceived opinions of my own. The 

 endeavour has been to describe correctly the specimens without attempting to generalize, 

 or to bind up into a whole scattered and fragmentary specimens, which may or may not 

 have been formerly connected with different plants. 



The opinions of various authors on the subject, up to the present time, are given in 



