8 



Mr. Salter described in 1H57 * fruj^nientH of tbsHil wood from 

 the Scottish Dovonian, hiivini; the structure of Ihitloxi/lon, though 

 very imperfectly preserved; and Prof. McNub has proposed f 

 the j^eneric name Pahtopiti/s for another speciuien of coniferous 

 wood collected by IIu'j:h .Miller, and referred to by him in the 

 '' TcHtimony of the Rocks." From Prof McNab's description, 

 I should infer that this wood may after all be frenerically iden- 

 tical with the woods usually referred to Dadoxyloii of linger 

 (^Ar<fi«'iirio:ci/l<ni ol' Krans). The description, however, does not 

 mention the number and disposition of the rows of pores, nor 

 the structure of the medullary rays, and I have not been able to 

 obtain access to the specimens themselves. I have described 

 thvcii n\Mic\c)i oi' D(nl()xi/I(»i from the Middle and Upper Erian 

 of America, all quite distinct from the Lower Carboniferous 

 species. There is also one species of an allied genus Ormnxt/lon, 

 besides the somewhat exceptional Prototoxites, which occurs in 

 the Lower Erian, not far above the top of the Upper Silurian. 

 All these have been carefully figured, and it is much to be de- 

 sired that the Scottish specimens should be re-examined and 

 compared with them. 



Prof. Alleyne Nicholson has kindly placed in my hands some 

 ancient plants which though not Scottish nor Devonian are of 

 interest in this connection. One of these is a specimen from the 

 Lower Ludlow of Bow Bridge. From its regular ramification, 

 its apparently woody structure, and its traces of rudimentary 

 leaflets, it may not improbably belong to the genus Psilophytoh. 

 If so, this genus occurs at about as low a horizon in Europe 

 as in Canada. 



The remarkable plants from the Skiddaw slates described by 

 Nicholson as Buthotrcphls Ilarknessi and B. radiata \ have 

 also been examined by me, as well as some additional specimens 

 from the same formation collected by Dr. G. M. Dawson. 

 Nicholson says of the latter species : — '' If its vegetable nature 

 be conceded, it can hardly be referred to the Algae." It seems 

 not unlikely, as Nicholson indeed suggests, that both plants may 

 belong to the same species, and that this had the habit of growth 

 of Annularia and resembled A. laxa of the American Devonian. 



i^ 



* Journal London Geological Society. 



t Transactions Edinburgh Botanical Society, 1870. 



X Geological Magazine, Vol. VI. 



