No. 3.] NOTES ON PROTOTAXITES. 173 



NOTES ON PROTOTAXITES. 



Mr. Carruthers, of the British Museum, having published iu 

 the " Monthly Microscopical Journal," some criticisms on Pro- 

 totaxites Logani from the Devonian of Gaspe, which he argues 

 may have been a gigantic sea-weed, Principal Dawson replies 

 m the same Journal. The following abstract of the reasons for 

 regarding Prototaxites as a conifer is deserving of publication 

 liere, as the species was first noticed in this Journal. . 



1. 3Iode of Occurrence. — This alone should suffice to convince 

 any practical palaeontologist that the plant cannot be a sea-weed. 

 Its large dimensions, one specimen found at Gasp^ Bay being 

 three feet in -diameter; its sendins; forth strong lateral branches, 

 and gnarled roots; its occurence with land plants in beds where 

 there are no marine organisms, and which must have been de- 

 posited in water too shallow to render possible the existence of 

 the large oceanic Algae to which Mr. Carruthers likens the plant. 

 These are all conditions requiring us to suppose that the plant 

 grew on the land. Further, the trunks are preserved in sand- 

 stone, retaining their rotundity of form even when prostrate; and 

 are thoroughly penetrated with silica except the thin coaly bark. 

 Not only are Algse incapable of occurring in this way, but even 

 the less dense and durable land plants, as Sigillaria? and Lepi- 

 dodendra are never found thus preserved. Only the extremely 

 durable trunks of coniferous trees are capable of preservation 

 under such circumstances. In the very beds in which these oc- 

 =cur, Lej)idod€ndra, tree ferns and FsUophyton^ are flattened into 

 mere coaly films. Tiiis absolutely proves, to any one having ex- 

 perience in the mode of occurrence of fossil plants, that here we 

 ^liave to deal with a strong and durable woody plant. 



2, Microscopic Structnre. — It would be tedious to go into the 

 numerous scarcely relevant points which Mr. Carruthers raises on 

 4his subject. I may say in general that his errors arise from 

 iieglect to observe that he has to deal not with a recent but a fos- 

 sil wood, that this wood belongs to a time when very generalized 

 and humble types of gymnosperms existed, and that the affinities 

 •of the plant are to be sought with Taxineoe, and especially with 

 -fossil Taxineae, rather than with ordinary pines. 



