YKRTEBKARIA. 95 



Glossopteris, a discovery which was confirmed almost simultaneously 

 by Oldham. 1 In both cases fronds of Glossopteris were found in 

 continuity with Vertebraria. 2 



Previously to Zeiller's discovery, several observers had described 

 fronds of Glossopteris attached to an axis, usually extremely 

 fragmentary, or at any rate not possessing the well-known features 

 of Vertebraria. McCoy, 3 in 1847, stated that he believed he had 

 "ascertained the rhizoma of this species" (G. Browniana); but 

 he did not give any particulars of his discovery. In 1849 Dana 4 

 figured a number of petiolate fronds of Glossopteris attached to 

 a rhizome, and, in his great memoir on the Flora of the Lower 

 (londwana Series, Feistmantel ° figured several others. But the 

 figures published by Etheridge 6 in 1894 are more important. 

 The specimen described was obtained from Mudgee, New South 

 Wales, and showed several leaves of Glossopteris Browniana in 

 continuity with a stem structure, described as a caudex by that 

 author, which presented none of the features characteristic of 

 Vertebraria. This specimen will be further discussed here. 



The explanations offered of the peculiar features exhibited by 

 this fossil have been varied. That suggested by Solms-Laubach 7 

 was that these rhizomes were cylindrical organs with a solid axis 

 surrounded by lacunae, which were bridged here and there by 

 transverse diaphragms of tissue, connecting the cortical tissues 

 with the central axis. That offered by Zeiller 8 in 1896 is much 

 more elaborate. He concludes that the features of Vertebraria are 

 derived as casts of the external surface of a winged rhizome. He 

 compares it with the rhizome of such a fern as Struthiapteris 

 germanica, Willd., in which a variable number of prominent, 

 projecting, longitudinal wings occur, which anastomose with 

 one another at different levels. The areas which form such a 

 characteristic feature of the fossil as seen in surface view, are 

 the interpolations of the matrix of the rock between the wings 



1 Oldham (97), pi. iii. 



2 A specimen showing continuity between these two organs has since been 

 found in the Clarke Collection in the Sedgwick Museum, Cambridge. 



3 McCoy (47), p. 151. ~ i Dana (49), p. 716, pi. xii, fig. 13c. 



5 Feistmantel (80), pi. xl a, fig. 1 ; pi. xli a, fig. 3. 



6 Etheridge & David (94). 7 Solms-Laubach (91), p. 366. 

 8 Zeiller (9G 1 ), p. 3J1 ; (96'). 



