GYMNOSPERM^. 11 



formerly supposed to possess near affinities with Araucaria and Cunninghamia, has been 

 thought by Saporta to belong to the Taxodieae, the very distinct types of foliage 

 included in the genus perhaps accounting for the divergent views. The widely-spread 

 Walchia and Ullmannia have been generally supposed to be Araucarian, although the 

 latter has also been placed in the Cupressinege. The Cycadacese were largely developed 

 throughout the Permian and until the close of the Jurassic period. 



In the Trias, besides some doubtful Cupressineae, two prevailing types occur — a form 

 of Voltzia, thought by Schiraper to be related to the existing Cryptomeria, and Albertia, 

 related to Dammara. Coniferous structure is abundant in the Lias, both the Araucarian 

 and Pine structures having been partially recognised, and we meet with the names Wid- 

 dringtonites and Thuyites. Four species of the latter are known from the Stonesfield slate 

 besides Araucaria ; and Solenhofen has been stated to have yielded Pinus, Araucaria, and 

 Arthrotaxites. The Secondary Period has in fact been described as the age of Gymno- 

 sperms ; and during the Jurassic especially they formed almost the entire forest vegeta- 

 tion. Schimper enumerates more than sixty species of Cycadaceae ; the Cupressineae and 

 Taxodineae are undoubtedly represented ; and what appear to be cones of true Araucaria 

 and Pinus have been met with in several localities at home and abroad. Ginkgo digitata 

 is indistinguishable from the existing Ginkgo, and the Pachjphyllum from the middle 

 estuarine series of Yorkshire bears a striking resemblance in its foliage to Araucariq 

 Cunninghami^ but possesses very much smaller and persistent cones. 



The Wealden Flora scarcely differs from that of the Jurassic. The scanty British 

 Cretaceous Flora, described by Carruthers, is almost entirely Coniferous ; Cedrus 

 having been met with in the Lower Greensand at Maidstone, Shanklin, and Folkestone ; 

 Pinus and Amber in the Gault, and Sequoia in the Gault and the Blackdown Beds. 

 The Cretaceous Flora of Hainault is also entirely Coniferous, and is described by 

 Coemans as containing links between the existing groups of Abies and Cedrus, Strobus 

 and Pinaster, Cembra and Strobus. Germany is said to have yielded cones of Dammara 

 and Araucaria from the Cretaceous. Cedar cones have also been found in the Wealden 

 of the Ardennes ; and Cedar and Pine cones occur in the Lower Cretaceous of Havre. 

 Most of these cones have, however, been described from unique or almost unique 

 specimens, and from external characters only. The Cretaceous Flora of Aix-la-Chapelle, 

 in which both coniferous fruit and foliage are abundant, warns us that very unexpected 

 internal characters may be combined, even in the later Cretaceous rocks, in a cone which 

 appears outwardly to be of an existing genus. Thus a cone bearing every outward resem- 

 blance to Sequoia possesses under each scale a number of Cupressineous-like seeds, while the 

 foliage approaches that of Libocedrus. The Columbea, or broad-leaved, and the Eutassa, 

 or needle-leaved, types of Araucarian foliage, are both met with in great abundance at Aix- 

 la-Chapelle and also in French localities ; their constant association together suggesting 

 that they may belong to a single dimorphic species. Several very anomalous Coniferae, 

 such as Inolepis and Cyparissideum, are met with in the Lower- Cretaceous Komeschichten 



