FROM THE SECONDARY ROCKS OF BRITAIN. 701 



The specimen is 10 inches long, but it is imperfect at both ends. The Ions? diameter <■ 

 17 inches, and the short 7 inches ; of this 4J inches are medulla, U inch wood and 1 



bases of leaves, which, however, are a good deal abraded. Scattered seconda 



4 iuvu nuuu, aim 1 



~ 



W 



the petioles. The only specimen of this magnificent Cycad hitherto found i io| 



v 



;ry perfectly preserved ; but there is more than sufficient to show that it belon to 

 genus, and is very different from the other species. 



From the Oolite strata of Helmsdale, Sutherlandshire, C. W. Peach. Esa. [""British 



Museum 



VII. Mantellia, Brongniart. 



1828. Mantettia, Brongn. Prodrome, p. 96. 



1828. Cycadeoidea, Buckl. Proc. Geol. Soc. p. 80; (1829) Trans. Geol. Soc. ser. 2. vol. ii. p. 395 



1836. Cycadites, Buckl. Geol. & Miner, p. 496. 



1849. EchinostipeSy Pomel, Amtlicher Bericht Aachen, 1847, p. 346. 



Trunk cylindrical, covered with the long permanent bases of the petioles. Medulla entirely cello) 



w 



gum-canals. Wood 



bases 



dullaiy rays. Fruits borne on secondary axes, generally protruding beyond the 



The names Mantellia and Cycadeoidea were published almost simultaneously and 

 independently. The earliest date I can discover for Cycadeoidea is the abstract of Buck- 

 land's paper, published in the Philosophical Magazine for September 1828. The authori- 

 tative abstract of the Geological Society has no date upon it. The name was adopted bj 



Buckland on the suggestion of R. Brown, who proposed it as an ordinal and not as a 

 generic name. The paper was published in full, with four plates, in the Transactions of 

 the Society, in 1829. On the first opportunity thereafter, in his Bridgewater Treati , 

 Buckland, at R. Brown's suggestion, withdrew his "provisional name," and adopted thai 

 of Cycadites, setting aside Brongniart's Mantellia, because it had already been employed 

 by Parkinson for a genus of sponges. This genus, however, has been rejected by subse- 

 quent writers, as it joins together species which have no affinity, by characters that arc 

 merely accidental (Toulmin Smith). Mantellia was proposed in the early, svstemat ic por- 

 tion of the ■ Prodrome.' In the passage of his work through the press, Bronun, art heard 

 of Buckland's Memoir, and referred to it in a note to the later, stratigraphy! poitoon 

 (p. 199). • He objects to the name Cycadeoidea, and retains in the text ^^^' 

 posed in the earlier part of the volume. Were Buckland's name ****£* 

 ought to be retained, because of its priority by a month or two; ^*°^^ 

 an error, was withdrawn by its author, and is in itself, as Brongmar and others 



stated, objectionable, it seems necessary to reject it in ^^^ £ ^ impor1:mt 

 The nmi..,lr»M. .fem. of this eenus have been fully nrvesti D ateu m ' 



. - -_ wn.cn UW » much of its value to the assistance g.ven t. , , u 



work by It. B own. The fossils differ from ***** - then f > - « 



t^ more distinctly rhomboids! petioles and the **£££* ^lie Z °~ 

 * the nature of the tissues and the method m •***££ numorouS ax illnry branch* 

 Proles are clothed with a dense amentum, and tne. -^^ , hen ^i^wn, nre 

 which bore small, simple, linear-lanceolate leaves, i Sometimes they ew 



hwken off at the point where they leave the bases of the pet.oles. ^ 



The remarkable stems of this 

 memoir of Buckland. which owes 



1 



