Manchester Memoirs, Vol. xliv. (1900), iV^?. 8. 9 



1849. Clodopldebis dcntala, Bronij^niart, Tableait, p. 105. 



C. IVilh'aiiisouis, Hud., p. 105. 



C. rccentior, Udd., p. 105. 



C. tenuis, ibid., p. 105. 



C- Whitbiensis, ibid., p. 105. 

 1854. Pecoptens Hiittojiiana, Morris, Cat. Brit. Foss., p. i 5. 

 1856. } DicJioptcris iiiicrophyila, VJxgno, Flora Foss. Oolit., 



vol. i., p. 122, pi. XV., fig. 5. 

 1869. Pecopteris {Aerostichites) Williamsoni, Schimper, 



Traitc Pal. Vcx., vol. i., p. 528. 

 1884. t'odea Williainsonis, Schenk, Palccontographica, vol. 



xxxi., ]:>. 168, pi. iii., fig. 3. 

 1889. CladopJdebis Virginiciisis, Fontaine, Potouiac Flora, 

 p. 70, pi. iii., figs. 3-8 ; pi. iv., figs. I and 4. 



C. parva, ibid., p. y^, pi. vi., figs. I -3. 



C. distans, ibid., p. yj, pi. xiii., fig. 4. 

 1889. Aspleuunii Whitbiciise, Yokoyama, Journ. Coll. Sci. 

 JapaJi, vol. iii., p. 32, pi. iii., fig. 3. 

 The identification of the numerous examples of 

 bipinnatc fern fronds of the Cladophlcbis type afforded by 

 the Yorkshire coast plant-beds is a difficult task, owing to 

 the considerable variation in the size and form of the 

 pinnules and the confused state of the nomenclature. It 

 is evident that the earlier authors multiplied unnecessarily 

 the number of specific names, and the confusion is ren- 

 dered worse by the fact that the same specific name has 

 occasionally been employed by different writers for species 

 which are no doubt distinct. As an example of the appli- 

 cation of the same name to distinct species, it may be 

 noted that the fern which Brongniart named Pecoptcris 

 Whitbiensis is in all probability distinct from that which 

 Lindley and Hutton referred to that species. Pccopteris 

 Whitbiensis^, as figured in the " Fossil Flora" is, I believe, 



^ The type-specimen of LincUcy and Hutton has not been found in the 

 Manchester collection. 



