STRUCTURE AND AFFINITIES OF LEPIDOSTROBI. 443 



tions of stems, it is evident that cones would have lain horizontally in 

 them, and that no washing or drifting could have induced the fragments 

 of these cones to lie with their axis parallel to them, or could have 

 introduced so many into one trunk ; and the latter would certainly have 

 been materially compressed had they received on one side the pressure 

 of the superincumbent shales. 



2. The stumps must have been submerged, and the fragments quietly 

 deposited from the water. Had the cones fallen into the stumps from 

 an overhanging forest, they would have alighted in all manner of irre- 

 gular positions, and in some cases overlain one another, which I have 

 never seen to be the case. 



3. The deposit appears to have been effected by the gradual subsi- 

 dence of the water, and not by a sudden rush or current. This again 

 is proved by the non-interference of the cones, and their uniformly 

 vertical position with respect to the Lepidodendron, a fact to which I 

 cannot too strongly call attention. It might be expected, that how- 

 ever tranquilly they were deposited, some irregularity should occur in 

 their arrangement, and such may yet be observed, though in the various 

 sections I have had the advantage of seeing made under my own direc- 

 tion none has been noticed. 



It is hard to account for the accession of so large a volume of 

 water as should submerge these stumps and deposit the fragments, 

 and yet exhibit no evidence of drifting in its course. The sudden fall 

 of a tropical torrent of rain, on a Lepidodendron forest, in which 

 were hollow stumps of these trees, must at once suggest itself. This 

 would both carry down the Lepidostrobi from the trees and float up 

 the fragments on the ground, depositing them together in the stumps. 

 Another effect of such a fall would be to break down some of the 

 older trees, whose decaying stumps would be prepared to enclose other 

 Lepidostrobi on the precipitation of the next similar torrent. 



It may be asked, why the same agent that produced all the deposits 

 over the coal, should not both have filled the trees and enveloped the 

 whole in silt. To this I would answer, that the action does not appear 

 to have been sufficiently violent, that the beds of iron-stone nodules, or 

 continuous seams of clay iron-stone in which this kind of fossil occurs, 

 bear no evidence of having contained the remains of a luxuriant forest 

 vegetation, similar to what the coal-shales present ; and that the repe- 

 tition of such phenomena as I have assumed to have filled the stumps 

 with fragments, is very likely to have impregnated the iron-charged 

 mud with carbonized matter in a state of the most subtle comminution, 

 which is the character of the carboniferous iron-stone wherein these 

 specimens are imbedded. 



The extreme fragility of the Lepidostrobi, displayed by these speci- 



