124 Remarks on the Ancient Flora of the Earth. 



from one another, as, on the other hand, the characters of the 

 transition rocks are distinguished from that of the old red sand- 

 stone. 



It is unsatisfactory, in investigations of this description, to 

 appeal to examples which do not rest on sufficiently accurate 

 determinations. Of this description, according to the testimony 

 of Brongniart, are the occurrence of Calamites arenaceus in 

 the Tceuper and in the variegated sandstone, and the Calamites 

 remotus or distans in the variegated sandstone and coal forma- 

 tion. Such examples, however, prove the very great similarity 

 of the forms which appear destined mutually to occupy one an- 

 other's place in the different periods of the vegetation of a for- 

 mer time. M. Brongniart has himself shewn us a remarkable 

 example of one and the same species in the strata of two per- 

 fectly different formations. It is, his Fucoides Brardii, (Hist, de 

 Veget, Fossiles, livr. i. p. 77, tab. ii. f. 8-19. Ann. d. Sc. n. xv. 

 p. 452,) found both in the Lignites under the chalk at Pialpin- 

 son, and also in the copper-slate {kupferschiefer) of Frankenberg. 

 But how shall we account for so striking a contradiction in the 

 principles and facts that should form their foundation ? 



In the comparisons hitherto adduced, we have intentionally 

 avoided returning to the remarkable discoveries of H.H. Elie 

 de Beaumont, and Ad. Brongniart, in the phenomena of vege- 

 table remains in the anthracite sandstone of the Southern Alps. 

 M. Brongniart, as is known, has here recognised in the strata be- 

 longing to the most decided lias formation, at least 15 species of 

 well preserved ferns, which were hitherto found together, only 

 in the old coal formation. In the same locality, he has detected 

 the appearance of Lepidodendrons, Sigillaria, Stigviaria and 

 Calamites, which were hitherto supposed to belong exclusively 

 to the coal formation. But the ingenious hypothesis which M. 

 Bi'ongniart has herewitli brought forward, (Ann. Sc. d. n. t. xiv. 

 p. 127.) and more recently expressly maintained, (1. c. tom. xv. 

 p. 375 note,) to explain these remarkable anomalies, is as little 

 satisfactory to us, as it is at variance with the general views en- 

 tertained by its author. 



If, however, the hypothesis of M. Brongniart, which we oppose, 

 is really established by further investigations, there still remains 



