THE FOSSIL FLORA OF THE YORKSHIRE COAL FIELD. 213 



summit, and finally by the primary pinnae being closer and narrower in regard to their 

 length, and by the rachis being always smooth." 



Without examining the original specimens, one is not warranted to propose the 

 union of Dactylotheca Gruneri with Dactyloiheca plumosa ; but in this last mentioned 

 species the pinnules are entire, dentate, or lobed, according to the position they hold 

 on the frond, and the rachis, though typically rough with small points, is, on the 

 specimen figured on my pi. ii. fig. 7, quite smooth on one part, whereas another portion 

 bears the characteristic little points. On the smooth portions of this rachis the little 

 points have probably been obliterated by pressure, but the same cause might have 

 equally well removed all evidence of them from the whole of the rachis. 



The Pecopteris Bioti, Brongt., as described and figured by Zeiller in the same work, 

 also seems to be very closely related to Dactylotheca plumosa.'* 



Sphenopteris crenata, L. and H., and Aspiclites silesiacus, Gopp. 



Stub, has expressed his opinion that Splien. crenata, L. and H., is identical with 

 Aspiclites silesiacus, Gopp., in his paper entitled " Momentaner Standpunkt meiner 

 Kenntniss uber die Steinkohlenformation, Englands." t 



That Pecopteris dentata belonged to Pecopteris plumosa was suspected by Eoemer 

 when he wrote his Beitr. z. geol. Kennt. des nordw. Harzgebirges in 1860.J 



Description of Specimens of Dactylotheca plumosa, Artis, sp., figured in the 



ACCOMPANYING PLATES I.-III.§ 



PI. I. figs. 1 and la. 



Specimen from Monckton Main Colliery, near Barnsley, Yorkshire. Horizon. — 

 Barnsley Thick Coal. Middle Coal Measures. || 



This may be regarded as the typical form of Filicites plumosus, Artis. The ultimate 

 pinnae are linear or linear-lanceolate, with alternate pinnules. The inferior basal pinnule 

 is placed in the angle formed by the union of the rachis of the ultimate pinna with 

 the stem from which it springs, and is always smaller than the immediately succeeding 

 pinnules. On the lower pinnae, it is generally composed of two lobes, the foremost of 

 which is usually sub-triangular, blunt, large, and the other — that next the stem which 

 bears the pinna — is rounded and slightly smaller. The corresponding pinnule on the 

 upper pinnae is sub -triangular and simple, and fills up the angle formed by the union of 

 the rachis of the pinna to its parent rachis, being united by its base in part to both. 

 The basal superior pinnule is large and usually slightly larger than any of the succeeding 

 pinnules. It is oblong-lanceolate, with an acute or slightly rounded point. The 



* hoc. cit., p. 99, pL ix. figs. 2-4. 



t Jahrb. d. k h. geol., Reichsanst, 1889, vol. xxxix. Heft i. p. 5. 



I Palceont, vol. ix. p. 34, 1860. 



§ I have figured small specimens, to enable me to give a greater number of forms. 



|| The same horizon as that from which the type of Filicites plumosus was derived. 



