IN THE STRATA OF THE CARBONIFEROUS SERIES. 37 



or subhexagonal markings, similar to those of Figs. 1, 4, 5, and 7 of the 

 same plate ; but separated from each other to a considerable distance. In 

 the same figure (9.) are dark spots resembling the single pores of the recent 

 Coniferse ; but, in general, the walls of the cellules are confusedly marked, 

 as if the reticulations had been obliterated by decomposition or crystalliza- 

 tion. 



Fig. 10. Is a longitudinal section parallel to the bark, in which is re- 

 presented a medullary ray of four or five series of cellules, and several of the 

 cellules of the woody fibre. 



Excepting in the circumstances of having the medullary rays usually 

 somewhat broader, and the areolae of the cellules separated, this plant is si- 

 milar to those of Craigleith. These circumstances, however, indicate a 

 generic difference, but as they exist in greater perfection in other fossils, 

 the remarks which I have to offer respecting it, may be deferred until we 

 have examined the tissue of another tree from a different locality, of the 

 same deposit, which appears to me to belong to the same species. I shall 

 merely state here that I propose giving to the Lennel Braes' plants the 

 name of Pitus antiqua. 



FOSSIL PLANTS FOUND AT TWEED MILL, ON THE BANKS OF THE RIVER TWEED, 

 IN BERWICKSHIRE. 



The remains of ancient vegetation which are found at Tweed Mill, 

 about a mile below Lennel Braes, resemble those of the latter locality in 

 their external appearance ; and it is probable that they belong to the same 

 deposit, or even the same stratum. I have obtained several very beautiful 

 sections of portions of these plants, which are represented in Plate VIII. 



Fig, 1. Represents part of a transverse section of a fossil stem found at 

 Tweed Mill. It is remarkable among the plants of the lower deposits for 

 the beautiful regularity of its tissue, which resembles that of the Coniferae, 

 presenting the usual hexagonal apertures of the elongated cellules, and very 



