18o7«] SALTER DEVONIAN PLANT-REMAINS. 73 



buted to " pressure during silicifi cation," in specimens of very similar 

 plants (Catamites, without articulations). The plants he described, 

 from near Lerwick, Shetland, were in the upper division of the Old 

 Red Sandstone, according to Sir Roderick Murchison*. 



Coniferous Wood. PL V. figs. 1 & 2. 



The above-noticed stems are 4 inches wide, and the fragments 

 measure more than 3 feet in length, without any tendency to taper 

 away. See fig. 1 . 



The surface is fluted pretty regularly by delicate longitudinal 

 ridges ; the intervening hollows being gently concave, not abruptly 

 grooved ; these ridges are tolerably regular and equidistant, without 

 being absolutely continuous ; seldom as much as a line apart, but 

 occasionally more. They are not interrupted by any transverse joints 

 as in Calamites ; and, from this circumstance, as well as from the 

 more solid texture of the stem, they might have been judged to 

 belong to the Stereocalamece of Unger, some of the genera of which, 

 Calamopitys or Calymma, would, from Unger' s description, present 

 a very similar appearance. 



With these there are long, curved and flattened linear specimens 

 (fig. 2), sometimes more than 4 feet long, and from an inch to 1^ inch 

 broad, very slowly tapering, and forked near the end. 



Both the straight and the curved stems are even-edged, as if ori- 

 ginally cylindrical ; and there are evident traces, in some portions, 

 of a central pith (probably not a woody axis, as the space in the 

 centre is now filled by the matrix), while the enveloping thick sheath 

 is all carbonized. This structure, a thick woody envelope, surround- 

 ing a central pith, may be that of a Conifer allied to the Dadoxylonf 

 of the Coal-measures ; and this is confirmed by the microscopic 

 sections (fig. lc) which have been kindly examined for me by 

 Prof. Quekett, who finds the ordinary coniferous structure — wood- 

 fibres dotted with disks , and these appear to have been in alter- 

 nating double rows, as in the modern Araucarians, and as in the 

 fragments of Coniferous wood, described by Hugh Miller, from beds 

 of Devonian age near Cromarty J. This dotted structure will, of 

 course, effectually distinguish these large stems from the woody struc- 

 tures (Aporoxylon), without disks to the wood-cells, which Prof. 

 Unger has lately § described ; otherwise the external appearance, and 

 even the mode of fossilization, are so similar in both, that I should 

 have provisionally referred our specimens to the same genus, had 

 there been no means of ascertaining the minute structure. 



Besides these large stems and roots, there are tapering branches, 

 an inch broad and often more than a foot in length, less regularly 

 striated than the stems, but still distinctly fluted all the way up ; 



* Loe. cit. 



f In Dadoxylon the wood-fibre has more numerous rows of disks than in the 

 Caithness fossils. 



t Testimony of the Rocks, p. 435. 



§ Denkschrift. Kais. Akad. Wissensch., Math. -Nat. Classe, vol.xi. 1856: Beitrag 

 zur Palaontologie des Thuringer Waldes, von R. Richter und F. Unger: p. 181, 

 pi. 13. figs. 3-11. 



