RADSTOCK SERIES OF THE SOMERSET AND BRISTOL COAL FIELD. 891 



oval line, within which is a variously bent transverse scar. Stems usually bearing 

 numerous aerial rootlet cicatrices, placed on the stem between the frond scars. 



Scars on stems deprived of their outer envelope, oval or elongate-elliptical, 

 upper and lower extremities rounded or pointed, and generally confluent, occa - 

 sionally showing within the scar traces of an inner oval cicatrice ; whole stem 

 striate. 



Remarks. — Several explanations have been given of the structure of the 

 scars of Caulopteris, some maintaining that the large inner circle of the frond 

 is closed ; others, that its superior margin is open, and that the two free ends 

 bend inwards, and thus form the characteristic "horse-shoe scar." Both of 

 these descriptions of the structure of the scars appear to be correct. 



Zeiller was the first to demonstrate the closed nature of 

 the inner circle of the scar of Caulopteris ,* inside of which 

 he detected a bent transverse band, which latter he regarded 

 as the true vascular cicatrice (text fig. 6). Grand' Eury, 

 however, states in his Flore carbonifere du Departement de la 

 Loire et du Centre de la France J that, though in the Upper 

 Coal Measures of the centre of France the Caulopteris with 

 " horse-shoe "-shaped inner scars are very rare, they do exist, Figi 6 . 



and on such a specimen he founds his Caulopteris protopter- Caulopteris peiugera, 



x j. j. j. Brongt., sp., showing inner 



oides, remarking, at the same time, that this form of Caul- closed vascular tract, with- 

 in which is contained the 



opteris was not so plentiful in France as he had seen it in transverse vascular cica- 



_. , _ , trice (copied from Zeiller, 



England. Grand Eury j was further able to show, from the half nat. size). 

 examination of a siliceous specimen of Caulopteris, that the inner closed circle, 

 as well as the transverse central scar, is a vascular tract. 



The genus has in England, as far as I am aware, only been found in the 

 Upper Coal Measures, and on the majority of the specimens the scar is of the 

 " horse-shoe " form. 



Another very interesting point has been brought out by Zeiller in his 

 paper to which reference has already been made, that those fossils, for which 

 Corda proposed the genus Ptychopteris § (of which Caulopteris macrodiscus is 

 the type), only represent the inner portion of Caulopteris, corresponding pro- 

 bably to the sheath of sclerenchyma that surrounds the central ligneous 

 cylinder. || The figure Zeiller gives of Caulopteris patria shows both these 

 conditions on the same specimen.! 



* " Note sur quelques troncs de Fougeres fossiles," Bull. soc. geol. d. France, 3 e s<Sr., vol. iii. p. 574, 

 1874-75. 



t p. 84. % Loc. cit., p. 84. § Flora protogcea, p. 76. 



|| Bull. soc. geol d. France, 3 6 s<5r., vol. xii. p. 203, 1883. 



IT Bull. soc. geol. d. France, 3 e s6r., vol. iii. pi. xvii. fig. 4. This is named on the plate Caulopteris 

 peltigera, Brongt., sp. (?), but has since been described as a new species by Grand' Eury under the 

 name of Caulopteris patria. See also Zeiller, Veget. foss. d. terr. houil., p. 100; and Grand' Eury, 

 Flore carbon, du Depart, de la Loire, p. 87. 



VOL. XXXIII. PART II. 3 M 



