348 M. Bi'ongniart on the different Floras which 



This is a vei'y distinct species. The description of S. nigra- 

 punctatus in Mr. Gray's ' Synopsis of the Reptiles in the British 

 Museum/ might be applied to this, but a comparison of the spe- 

 cimens shows that they are not at all alike; nigro-punctatus heing 

 much larger, of a deeper brown, with the specks scarcely dis- 

 cernible. 



The trivial name is formed from o^v^, sharp, and plv, the nose. 



XXXI. — Chronological Exposition of the Periods of Vegetation and 

 the different Floras which have successively occupied the surface 

 of the Earth. By M. Adolphe Buongniart. 



[Concluded from p. 203.] 



III. Kingdom of the Angiosperms. 



The predominant character of this last transformation of the 

 vegetation of the globe is the appearance of the angiospermous 

 'T>^'cotyledons, of those plants which at the present time consti- 

 , pite more than three-quarters of the vegetable creation of our 

 6poch, and which appear to date their predominance from the 

 origin of the tertiary formations. For a long time I imagined that 

 these plants had not begun to present themselves until posterior 

 to the chalk, with the first beds of the tertiary formations ; but 

 more recent researches have shown that the beds belonging to 

 the cretaceous formation already present certain very positive 

 examples. 



The plants even extend back to the commencement of the cre- 

 taceous epoch ; for it is certain that several well-determined spe- 

 cies exist in the Quadersandstein and the Planerkalk of Germany, 

 which appear to correspond to the gres vert of France or green- 

 sand of English geologists, although this formation has never 

 displayed any of them in France and England, and presents only 

 a few examples of Cycadese, Conifei'se and marine plants ; but in 

 the south of Sweden, at Kopingue in Scania, a few specimens of 

 dicotyledonous leaves present themselves also associated with a 

 species of Cycadea in beds which have been referred to the cre- 

 taceous glauconia or greensand ; so that the cretaceous formation, 

 taken as a whole, appears to constitute a first period of the reign 

 of the Angiosperms, forming, so to speak, the transition between 

 the vegetation of the secondary formations and that of the ter- 

 tiaries, presenting, like the former, still a few Cycadese, like the 

 latter, already a few angiospermous Dicotyledons, and thus pre- 

 luding the considerable development of the latter plants in the 

 following period. This period is, moreover, characterized by 

 several Coniferse peculiar to it, which appear very distinct from 



