300 



SUPPLEMENTAUY NOTES. 



been removed. Part of the coaly bark remains at c. The decorticated part of the trunk is covered 

 with minute scales as far as the point h, a few inches below the first ramification of the roots. 



Fig. 3. 



SIEM OF SIGILLAEIA ALTERNAHS, ^ natural sizC. 



The carbonaceous crust investing the roots was thick at the upper part, but gradually became 

 thin, and at a, and b, was a mere friable pellicle, that fell off iipon the slightest touch. 



Shale with coal-plants— 



Fig. 4. 



The exact position of the tree in relation to the underlying coal is shown in the above section. 

 Fig. 4. Immediately over the coal there is a bed of hard shale, six inches in depth, in which no 

 fossils ai-e found; this is overlaid by a softer shale abounding in coal-plants; all the upright 

 stems were rooted in the six-inch shale. Upon clearing the base of this tree, a complete set of 

 conical tap-roots was discovered, arranged as in the annexed sketch. Fig. 5. There are four large 

 tap-roots in each quarter of the stump, and five inches below these another set of smaller tap- 

 roots ; the total number amounting to eighteen. The horizontal roots are seen to branch off in 

 a regular manner, the base being divided into four nearly equal parts by deep channels, extending 

 fi-oni the centre to the points i, k, I, m. 



