KUKM nil; COAl.-HiKMATION (>F NmVA SIOTIA. 



841 



nnd Ktill in«»re fully in (hat on Sliflllariit iiiul its iiIUi-h in 1>7<**, 

 BC'voriil (liHtinct typi'8 ot' Sif>;illiiri<)i(l trees ; thoujrh whether wc ean, an 

 Hiifff^ested in those papers, weparate those with the Chil/irttrin aiitl 

 I'avuUtria styles of inarkiii;j:s from the other Si(jiH<iriif, is st ill douht- 

 ftil. The FreJieh authors iihove cited rej^ard their S, ilfijitns and 

 S. HitinuloHd, whieh are of the Faviiltirln type, us true .S'/'/////fn(P, and 

 hohl that their woody eyliiuler, with its Hltres in radial s«'ries and 

 with medullary rays and radiatiufjhundles proceediii;; t'roui (he inn»'r 

 eylinder, allies these trees with the f^yiunospenuous e.\o;;eus. Wil- 

 liaujHon rof^ards his Si<iilhiri.<f of the iJi/ila.viflon type of structure as 

 prohahly eryi)to};an)()us and allied to Lipiifodi inlron, thou{?lj nuiin- 

 tuiiiing tliat the structure of tlu^se stems is truly exo<;eiious. There 

 can scarcely be any doultt that the hijjher type of SiijiUtifia, which 

 I dcscrilted in 1^7<', and which, I thiuk. rei)resents the ordinary 

 coarsely-ribbed s])ecies of the type of my >S'. linm'nii, are allied to 

 {yymnosperms. Prof. Newberry and (he writer have adduced stroTij; 

 circumstantial evidence to show that i^i;illl<irl<f produced the fruits 

 known as Tri'/onocdr/Ki, found so constatitly witli their renuiins. 

 (ioldenberg, on the other !iand, has tiffined a sort of strobile as at- 

 tached to iSitfiU'iria. Williamson luis ti<j;ured fruit-scars, which he 

 repiards as attachments of cones. I have tif^uredt wcU-pn served 

 fruit-scars of two species which cannot have borne strobiles, but may 

 very probably have l)orne l^-ii/imocai'jm or racemes of such fruits. 

 These facts, 1 think, taken alonj? with those of structure, tend to show 

 that there may l)e included in the {^enus Sli/illarin, as orifiinally 

 founded on the markings of the surface, species widely dilfering in 

 organization, and of both gymos])cnnous and acrogenous rank. This 

 conclusion is further confirmed by the fact, which 1 have long ago 

 amply demonstrated in my papers on the structures and nxale of 

 accumulation of coal, that in the great coal-beds tissues of gymno- 

 spermous character, but distinct from those of Conifers, exist to nii 

 enormous amount, while no other trees are found in connexion with 

 these beds to which such tissues can 1)e referred excejjt iho S I fjH /arid' . 



Should this view be finally established, these trees will present an 

 interesting link of connexion between the gynuiospenns and the 

 higher cryptogams. They connect the Lcj>khulnuh-d with the Cycads 

 and Conifers in the gradations of exogenous structure seen in their 

 wood and bark, and also in the remarkable transitions which they 

 exhibit between woody tissues of the discigerous type and those sca- 

 lari form tissues which, tliongh resembling scalariform vessels ])ro- 

 perly so called, yet in these plants are evidently arranged in the 

 manner of woody fibres, and take the place of these in the construc- 

 tion of the stem. 



The tendency of investigation of late has been to convey (he im- 

 pression that the Sigillarioid and he]»idodendr()id trees of the coal- 

 formation were of one somewhat uniform aiul monotonous tyjte. On 

 the other hand, the great number of species of these trees indicated 



* Qanrt. .Touni. Oenl. Soc. toI. xx\ii. (1S71) p. 147. 



t Quart. Joiirii. Oeol. ^oc vol. xxii, Kvport 'm I'\)f»^il Plants nf tlio Lower 

 Carboniferous: 1873. 



