MEDULLA. 



II 



tute the primary medullary rays (fig. 7, V b'). Vegetable fragments which do not 

 belong to the individual Stigmarian root, especially the ubiquitous rootlets of other 

 individual Stigmaria?, frequently found their way into the fistular cavity. Several 

 writers have seen the vascular bundles of these rootlets within the medullary cavities 

 and have mistaken them for elements belonging to the root within which they 

 observed them. In other words, they supposed that Stigmaria had not only a solid 

 medulla, but that vascular bundles ran longitudinally through the centre of that 



again indebted to my experienced and accurate friend Mr. Wild for a good example represented in 

 the accompanying diagram. (Xylograph 3.) 



Xylograph 3. 



Coal. 



Fireclay. 



This example is from the Dandy bed of coal, nearly fifty yards above the Arley Mine, at 

 Tulledge, near Burnley. The specimen was a good Stigmarian root which was traced from near the 

 roof of the coal (the latter being about two feet in thickness), through which it gradually descended, 

 and entered the fireclay seat below. About four feet of the root was in the coal and nearly nine feet 

 in the seat. The root in this case had been preserved from destruction by the agencies referred 

 to by Mr. Bowman, quoted on a previous page, viz. by the fact that its cast had been filled at an 

 early period with sandstone derived from patches of similar sandy material found in the roof of the coal. 



The next diagram represents a state of things met with in November last in Mr. Wild's colliery 

 at Bardsley known as the Pomfret Mine. 



Xylograph 4. 



In this instance a is a Stigmarian " stool " embedded in the fireclay. Immediately above it, in the 

 roof of the mine, was a " pot-hole," b, i.e. a hole from which part of an aerial stem was extracted and 

 which there can be no doubt was the stem of the roots a. 



Xylograph 5 represents another instance just discovered at the Bardsley Colliery, where there are 

 two seams of coal separated by a thin parting of clay. Mr. Wild found a large stem ascending 



