Manchester Memoirs, Vol. xliv. (iQOo), No. S. 7 



abundantly represented in the Inferior Oolite Flora, and 

 exhibit considerable variations as regards both the sterile 

 and fertile segments. The wide range of variation suggests 

 the presence of several species of closely allied ferns, but, 

 on the otherhand,the more extreme forms are connected by 

 numerous intermediate exam[iles, and it seems practically 

 hopeless to separate the various types into species dis- 

 tinguished by well-defined characteristics. 



The type-specimen of Sp/ieiiopteris argiita L. & H., 

 was found at Gristhorpe and sent to the authors of the 

 Fossil Flora " by Mr. Williamson, junior," who added a 

 description of the specimen, and expressed his opinion 

 that the fern was distinct from Sphcnoptcris hynicnopJiylloides 

 Brongn. and ^\ stipata Phill. As shown in fig. i, the 

 specimen, which is on the whole accurately represented in 

 Williamson's drawing {Fossil Flora, pi. clxviii.), consists 

 of a portion of a pinna 5 '5 cm. long ; the axis is slightly 

 winged, and bears cuneate pinnules, with a deeply dis- 

 sected lamina ; the ultimate segments are acuminate and 

 entire or more or less deeply lobed. The venation, which 

 is indistinctly shown, is of the St)hcnopteris type. 



I have adopted the name Coniopteris in place of 

 Sphenopteris, on the ground that the fertile specimens of 

 this Jurassic species, in which vS. arguta L. and H. is 

 included, enable us to assign the plant to a definite family 

 of ferns — the Cyatheacea;. Brongniart^ proposed the 

 generic term Coniopteris for ferns possessing characters 

 intermediate between Pecopteris and Sphenopteris, and 

 which agree in the form of the sori with the recent 

 Dicksonia^. The specimen figured by Lindley and Hutton 

 is of the Sphenopteris type, but the sori point to a close 

 affinity with Cyatheaceous ferns. Solms-Laubach'^ has 

 also advocated the application of Brongniart's genus 



^ Brongniart (49), p. 26. ^ Solms-Laubach (91), p. 157. 



