72 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 20, 



2. On some Remains of Terrestrial Plants in the Old Red 

 Sandstone of Caithness. By J. W. Salter, Esq., F.G.S., 

 of the Geol. Survey of Great Britain, &c. 



[Plate V.] 



Numerous fragments of plants have for several years past been 

 discovered in the Old Red Sandstone of the North of Scotland ; but 

 as yet a few only have been figured. The specimens have now been 

 gathered together by the Director of the Geological Survey for the 

 purpose of illustration. 



As no experienced botanist has yet been willing to take up such 

 obscure relics, I have thought that some general notes on this old 

 flora might be useful, if only to lead the way to a more critical exa- 

 mination of the specimens. Some of them will be figured also in the 

 second edition of " Siluria." 



The best that I have seen are in the collection of Mr. John Miller, 

 of Thurso, who has for some time directed his attention to these Devo- 

 nian plants, and at the request of Sir Roderick Murchison, who long 

 ago observed them, has most kindly entrusted to us the whole of his 

 collection. Mr. R. Dick, of the same place, has also aided largely in 

 these discoveries. Mr. C. W. Peach has more lately found similar 

 plants at Wick, and Dr. Hamilton in Orkney. I have examined all 

 these collections, and many of the specimens are now placed in the 

 Museum of Practical Geology. 



The fossils are preserved in hard, grey, sandy flagstones, which 

 are in many cases abundantly marked with impressions of Annelide- 

 burrows in pairs (PI. V. fig. 6) ; and these probably indicate that 

 there was no great depth of water where these beds were deposited. 

 The late Hugh Miller has even suggested that these strata may have 

 been accumulated on an extremely level muddy shore*. 



The most striking of the fossils are large stem-like fragments, of 

 every size up to 3 feet in length, either straight and finely fluted, 

 stems (PI. V. fig. 1) ; or curved and occasionally branched, roots 1 

 (PI. V. fig. 2). These are all highly bituminized, and divided by 

 oblique lines, which are evidently only due to mineral structure. 

 Indeed the most striking feature about all these specimens is the 

 mode in which they are mineralized. The carbonaceous substance is 

 cleaved throughout in a series of oblique planes, which in the long 

 root-like specimens (fig. 2) are set quite close (2 or 3 in the space 

 of t^h °^ an inch), and cleave the substance in lines perfectly 

 parallel, whatever may be the position or curvature of the specimen. 

 In the stems (fig. 1), these cleavage-lines are generally far wider 

 apart, often \ of an inch ; and they form fissures, often filled up by 

 siliceous matter. Owing to the further compression of the wood, 

 the silex stands out in relief, and forms impressed lines upon the 

 matrix, which may readily be mistaken for the marks of structure. 

 Similar diagonal lines have been noticed by Dr. Hookerf, and attri- 



* Testimony of the Rocks, p. 437. 



f Quart. Journ. Geol. Soc. vol. ix. p. 50. 





