10 STIGMARIA FIC01DES. 



to the delicate structure of its cells this tissue was frequently destroyed ; the area 

 which normally represents its position being often entirely empty. But I have 

 obtained numerous examples in which this medulla is preserved as a very thin layer, 

 Hning the vascular cylinder, as represented at Plate IV, fig. 7, a. The medullary 

 character of this layer is demonstrated by the way in which extensions of it consti- 



Another point respecting which some friends entertain douht refers to the possibility of the secondary 

 roots of large trees, whose trunks and primary roots stand upon the coal, ever being sent into and 

 through the coal so as to reach the subjacent fireclay. The fact that these large roots are so constantly 

 cut off by the coal is in itself significant. "We know that such roots attained to a length of as much as 

 fifteen and twenty feet, yet those referred to are abruptly truncated by the coal-seam at not more than 

 three or four proximal feet of their length. "What has become of the remainder of each such a root 

 if it has not entered the vegetable soil now converted into coal ? The original description of the Dixon 

 Fold trees (Plate I) was written by JohnEddowes Bowman, F.G.S. and F.L.S., whom I knew long and 

 well as an experienced and accomplished geologist, trustworthy in the highest degree. He says of these 

 trees, " The material on which they stand is a thin bed of pure bright coal eight or nine inches thick. 

 It has already been said that the roots do not penetrate the coal, but are abruptly cut off at its surface, 

 and that the immersed portions have probably been acted upon by the chemical changes going on in 

 the surrounding vegetable mass so as not to be distinguishable from it (" On the Fossil Trees lately 

 discovered on the line of the Bolton Railway near Manchester," 'Transactions of the Manchester 

 Geological Society,' vol i). Having been personally familiar with these trees at the time of their 

 discovery, I can vouch for the correctness of my old friend's description. The Duckinfield tree, also 

 referred to above, affords a still more striking example. The truncated stump of the aerial stem was 

 found with the bed of coal, two feet six inches thick, resting upon its broken, upper extremity. Not one 

 of the long roots, now in the Museum of the Owens College, went deeper into the fireclay than three 

 feet. Hence the stump, when a living tree, must have ascended high above the upper surface of the 

 vegetable soil now represented by the coal-seam. It would be easy to multiply examples of a similar 

 kind, found both here and in the North American coalfields. Not unfrequently such trees are met 

 with apart from coal-seams. The St. Helen's tree was in this position, and many of the trees in the 

 Oldbam Forest were similarly circumstanced. Some of these were very young ones, and may not 

 have lived long enough in the positions occupied by them to accumulate, over their roots, sufficient vege- 

 table soil to form a bed of coal ; or such as was accumulated may have been washed away again before 

 sedimentary sand and mud took its place. That such local denudations have occurred is well known. 

 In a Memoir read to the Manchester Geological Society, on the 2nd of February last, Mr. "Wild, 

 speaking of a coal to which he has recently sunk, says, " In the seat of this mine, which is a brown 

 stone, Stigmarise are both abundant and good, and both roots and rootlets pass through four 

 different layers of rock and shale to the depth of six feet below the coal. At about ten yards below 

 the coal (New Mine) is found a coally-looking floor or parting, overlain by dark shale containing very 

 well-formed septaria, whilst under the parting is a well-developed coal-seat or warrant (certainly a 

 misnomer in this case), four to five feet in thickness, the Stigmariae in which are exceedingly good. 

 Such cases of an under-clay crowded with once vigorous roots and rootlets capable of supporting 

 gigantic trunks with foliage and fruit, being almost entirely robbed of the vegetation it had succoured 

 by that relentless disturber, denudation, are by no means rare." Familiar with the pit to which Mr. 

 Wild refers, and having collected some of the magnificent Stigmariae of which he speaks, I can 

 confirm his statements respecting these seat-beds and their vegetable contents. 



But I am further asked by one of my doubting friends, has anyone ever found a Stigmarian root 

 or Sigillarian stem passing through the coal into the fireclay below ? To this I answer yes. I am 



