594 MR ROBERT KIDSTON ON 



Locality. — Ysguborwen Colliery, Aberdare. 



Horizon. — 7 Foot Seam. 

 Locality. — Beaufort. 



Horizon. — 2 Feet 9 Inch Seam. 



Alethopteris, Sternb. 

 Alethopteris lonchitica, Schl., sp. 



Alethopteris lonchitica, Schimper, Traite d. paleont. veget., vol. i. p. 554 (Ref. in part). 

 * Alethopteris lonchitica, Kidston, Trans. Roy. Soc. Edin,, vol. xxxvii. p. 330. 

 Pecopteris lonchitica, Brongt., Hist. d. veget. foss. p. 275, pi. lxxxiv. 

 Filicites lonchiticus, Schloth., PetrefactenJc, p. 411. 



Pecopteris urophylla, Brongt., Hist. d. veget. foss., p. 290, pi. lxxxvi., 1833. 

 Schlotheim, Flora d. Vorwelt., p. 55, pL xi. fig. 22. 



Remarks. — The type of Brongniart's Pecopteris urophylla from Merthyr Tydvil, 

 which is preserved in the Collection of the Geological Society of London, has kindly been 

 lent me for examination, and I find that it differs in no point from Alethopteris (Pecop- 

 teris) lonchitica, — as Brongniart's own figures show, — except in its possessing a narrow 

 flattened border to all the pinnules ; even the long simple terminal ("heterophyllous") 

 pinnules show this same character. 



Brongniart supposed that this flattening of the margins of the pinnules indicated the 

 position of a marginal fructification, as in the recent Pteris. But even granting that 

 this flattened marginal band does arise from the presence of marginal fructification, the 

 most that can be said of the fossil is that it is a specimen of Alethopteris lonchitica in 

 fruit, — the presence of the fructification, all other characters being the same, cannot be 

 taken as a distinctive point by which to separate it from another species with which it 

 otherwise agrees in all respects. 



Proceeding further, it is open to doubt if this flattened band-like border is really 



produced by the presence of a marginal fructification. There is no evidence of any 



sporangia — only the upper surface of the frond being shown. On the other hand, it is 



difficult to explain how pressure could have produced this marginal flattened band, which 



is really on a lower level than the convex well preserved pinnules. What may be its 



morphological importance I do not know, but I may add that I have observed the same 



flattening of the margins of the pinnules on Alethopteris decurrens and Alethopteris 



aquilina. 



Upper Coal Measures (Upper Pennant Series). 



Locality. — Mynydd Newydd, near Swansea. 



Horizon. — Big Vein (next above Mynyddislwyn). 



Transition Series (Lower Pennant Series). 



Locality. — Bute Quarry, Pwllypant, near Caerphilly. 

 Horizon. — Under Mynyddislwyn Seam. 



