176 REMINISCENCES OF 



Ayrshire. Anyhow, they were killed, and as time 

 rolled on their upper stems and branches perished 

 and disappeared, nothing remaining but their dwarf 

 stumps, such as are common where what are called 

 submarine forests exist. 



Wherever we discover such trees preserved in a 

 fossil state we find that the inner layers of the 

 bark are the first to disappear, the outer cortex 

 being composed of a strong fibrous material, which 

 resists destructive agencies. But it was these inner 

 layers of the bark that held the central vascular 

 axis in its place. At the same period the trees must 

 have become submerged, when the water which over- 

 flowed them would float out all the loose decaying 

 vegetable matter which the protective bark on 

 each trunk would otherwise have retained within its 

 cylindrical walls. The state of all our stems ex- 

 cepting one shows, that not only the fragments of 

 the inner cortex were thus removed, but that each 

 central vascular axis floated out along with them. 

 Hence it is that we found the interiors of most of 

 these trees filled with pure volcanic ash, almost un- 

 mixed with any vegetable elements. But something 

 more had happened to one exceptional tree, a large 

 transverse section of which is now in the entrance 

 of my house, whilst the remainder I presented to 

 Owens College, and it is now one of the treasures 

 of the geological museum. 



This tree must have passed through the same 

 stages of decay, and the disappearance of its inner 



