CONCLirSIOH-. 311 



species A. minor. The species of Oiozamites, which played a very- 

 prominent part in the composition of the Inferior Oolite flora, 

 afford points of contact with both Ehaetic and "Wealden types, 

 but this genus is primarily characteristic of Jurassic floras. I have 

 already pointed out that some of the Jurassic Cycadean fronds 

 exhibit a closer approach to the fronds of ferns than is the case 

 with modern Cj^cads, with the exception of Stangeria pwraioxa} 



Nihsonia compta is one of the commonest species in the Yorkshire 

 Coast flora, but its close resemblance to N. polymorpha and other 

 Ehaetic types detracts from its value as an index of geological 

 age. In the Wealden flora the genus Nilssonia is represented by 

 a smaller-leaved form, N. Scliawmbwrgemis. No example of the 

 genus Cycadites has so far been recognized among the East 

 Yorkshire plants. 



Ctenis faloata is a characteristic species in the Inferior Oolite 

 flora; the larger form, described as Ctenis sp., recalls some of the 

 species described by Eaciborski from Poland as well as certain 

 EhsBtic examples from Scania and elsewhere. 



Podozamites lanceolatus is a Mesozoic type of wide geographical! 

 range occurring chiefly in Ehsetic and Jurassic strata, and less 

 abundant in more recent beds ; it is not improbable that this species 

 may be best compared with the conifer AgatMs uustralis rather 

 than with Cycads. 



CoNiPEHiE. — The Conifers are much less abundant than either 

 the Ferns or Cycads ; it is impossible to determine how far this 

 may be taken as an indication that they played but an insignificant 

 part in the vegetation, or as resulting from the less favourable 

 position of the Conifers — which probably occupied higher ground 

 farther from the area of sedimentation — as regards the chances 

 of fossilization. In all probability the Coniferae were less 

 numerous and represented by fewer types than either the Cycads 

 or Ferns. So far as we are able to form an opinion as to the 

 systematic position of the Inferior Oolite Conifers, it would 

 seem that their aflS.nities are chiefly with the Araucarinae. 

 Nageiopsis anglica represents a tjrpe which is much more abundant 

 in North American beds of "Wealden or Upper Jurassic age than in 

 European regions ; it may be compared with Araucaria Bidwilli 

 or with certain species of Podocarpus. Arancarites Phillipsi is 



1 Ante, pp. 170, 203, 208, 212, etc. 



