CONCLUSION. 309 



Osmundacem. — Todites Williamsoni must have been one of the 

 Tuost conspicuous and abundant ferns which flourished during the 

 Jurassic period. It is possible that Sphenopteris princepa should 

 ■also be included in this family, but we lack such convincing 

 -evidence of afB.nity as is afforded by the fertile specimens of 

 Todites Williamsoni. The Ehsetic species described by Schenk as 

 Aorostiehites Qoeppertianus appears to be barely distinguishable 

 irom the Inferior Oolite species of Todites : from the "Wealden 

 plant-beds no satisfactory representative of the Osmundacese has so 

 far been recorded. 



The Cyatlisacem are represented by such species as Coniopteris 

 Jiymenophylloides, one of the most characteristic of the Yorkshire 

 Coast ferns, C. qmnquelola, and C. argida. There is a striking 

 resemblance between some of these fossil Cyatheaceae and the isolated 

 Tecent fern Tliyrsopteris elegans. The Inferior Oolite flora was 

 ■characterized by an abundance of ferns of the Thyrsopteris type. 



Among Wealden ferns we have the genus Protopteris, which 

 may probably be included as a member of the Cyatheaceae, a type 

 which extends into stUl more recent geological periods. 



Schizaacece. — In addition to the somewhat doubtful Ruffordia 

 Goepperti of Wealden and Inferior Oolite age, we have an excellent 

 example of this family in the widely distributed KluMa exilis, 

 a species which may also be closely matched among Wealden ferns. 

 Neither the Cyatheaceae nor the Schizaeacese are represented by 

 any well-authenticated Ehaetio species, but in the Palaeozoic genus 

 ■Senftenbergia we have a stiE. older type which exhibits well-marked 

 Schizaeaceous characters. Klukia exilis agrees precisely as regards 

 the structure of the sporangia with the living members of the 

 family, but in the form of the frond it difiers from the modern 

 representatives of the Schizseaceae. 



The Yorkshire Coast Flora has not so far yielded any recognizable 

 •examples of the Gleioheniaceae or the Marattiaoeae ; species of the 

 former family are known to have existed daring the Wealden 

 period, and we have a representative of the latter family in the 

 Ehsetic fern Taniopteris Muensteri. Prom the Jurassic plant-beds 

 •of Poland, Raciborski has described a member of the Marattiacese 

 under the name Bancea. Neither the Hymenophyllaceae nor the 

 •Ophioglossaceae appear to have any representatives among the 

 Inferior Oolite plants. The statement that certain families of ferns 

 are not represented, simply means that we have not discovered any 



