392 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 22, 



roots, B and C, having similar external characters to the main ones. 

 Each of the latter measures fifteen inches across. Each of these 

 again, after running sixteen inches, dichotomizes into four roots, D, 

 E, and FG, which respectively measure ten and a half inches across 



at their commencement. The outsides of these latter roots present 

 a rougher appearance than the secondary ones for about two feet, 

 after which they gradually assume all the true characters of Stig- 

 maria, with depressed areolae, &c., never again exhibiting traces of 

 dichotomization. The roots marked D and E run upwards more 

 than those marked F and G, the latter extending more in a hori- 

 zontal direction. Some of the Stigmaria roots are slightly com- 

 pressed, while others are nearly cylindrical in different parts ; but 

 for fifteen feet, the distance they have been traced, they average 

 about five inches across, without any signs of terminating. Their 

 outsides are composed of ironstone, but internally they consist of a 

 ver}'^ fine-grained silty sandstone, and show distinct evidence of an 

 internal pith or cylinder. The latter however does not show struc- 

 ture. It is a singular fact that the stem of the plant should be filled 

 with dark-coloured fire-clay and the roots (especially the Stigmaria 

 portion of them) with a different material *. 



The St. Helens' trees appeared to me to exhibit in situ all the facts 

 necessary to prove Stigmaria to be the root of Sigillaria, and thus 

 firmly fix the origin of all seams of coal having such roots in their 

 floors without having to resort to the drift hypothesis. It is satis- 

 factory to have my views confirmed by a specimen which everybody 

 who will go into the museum where the fossil is deposited can see 

 and judge for himself. The extraordinary regularity which prevails 

 in the roots of Sigillaria was noticed in the paper published by myself 

 and my friend Mr. Harknessin the ' Philosophical Magazine' of Oc- 

 tober last. The Dukinfield tree confirms our opinions on this point. 



At St. Helens the trees had eight feet of silty clay to run into, 

 and the roots there struck down at angles varying from 50° to 60° 

 before they took a horizontal direction, and exhibited all the cha- 

 racters of Stigmaria. In the present instance, the roots having to 



* The late Mr. Bowman, in his description of the fossil trees at Dixon Fold 

 (Trans, of the Manchester Soc, voL i. p. 129), attempts to explain the removal of 

 the inner portion of the tree by decomposition after entombment, and its subse- 

 quent filling with sand and clay from above. So the dark-coloured fire-clay may 

 possibly have come from the floor of the Stone mine after the roots had been pre- 

 viously filled with silty sand from some prior deposit. 



