J. Sfarkie Gardner — Development of Dicotyledons. 161 



world, may be illusory. The first appearance of Dicotyledons re- 

 mains, however, iu any case remarkably sudden, and we ai'e still 

 left with very little clue as to how and by what progressive steps 

 they originated. 



The flora of Aachen is, I believe, the most extensive European 

 Cretaceous flora known. Very little concerning it has been pub- 

 lished, and neither it nor any other Cretaceous flora with Dicotyle- 

 dons is adequately represented in any Museum in Great Britain. I 

 had fortiniately, however, an opportunity of going carefully through 

 Dr. Debey's collection, and of visiting the quarries whence it had 

 been obtained and even finding a few specimens. Its great antiquity 

 is obvious, despite the presence of dicotyledonous leaves, for the 

 Coniferge depart very widely from existing species, or even from 

 those of the Eocene, and among the Ferns there seem to be repre- 

 sentatives of two singularly archaic genera, Matonia and Thyrsopteris, 

 which do not occur in any Tertiary formation in Europe. I did 

 not see, and am not aware of any good grounds for the supposed 

 identifications of the Dicotyledons with living genel-a, such as Oak, 

 Beech, Fig, Willow, Poplar, Bog-myrtle, nor with any genera of the 

 Proteaceas and Myrtacese. The leaves are of considerable variety of 

 form and size, lobed, serrate and simple. There are many other 

 localities in Europe from which similar Cretaceous floras have been, 

 obtained, but I am not so well acquainted with them. 



A more ancient flora is that of Kome in Greenland, from which 

 a single though apparently perfectly developed dicotyledonous leaf 

 has been obtained, and referred, upon no ground whatever, except 

 a fancied resemblance iu the form of the leaf, to Populus. 



The newer Cretaceous rocks of Greenland are said to contain 

 species of a large number of existing genera ; but these appear, with 

 trifling exceptions, to be all determined upon the greater or less 

 resemblance of the fossil leaves to some of the forms of leaf met with 

 in such genera. The ages of the deposits are apparently very un- 

 certain, and no specimens have jet found their way to our museums. 



Another extensive and supposed Cretaceous flora from Vancoiiver's 

 Island has frequently been referred to ; but no specimens, so far as 

 I know, exist in England. 



A yet more extensive flora is that from the Dakota group at the 

 base of the American Cretaceous series. The leaves are mostly 

 lobed, resembling those of Platanus, Sassafras, and Liquidambar, 

 but seemingly no fruits have yet been identified. A remarkable 

 fact about this flora is, that while utterly disconnected from any 

 other supposed Cretaceous flora in Europe, it bears a resemblance 

 to the English Lower Eocene flora. 



Cretaceous rocks containing Dicotyledons are also met with in 

 New Zealand, but as yet little appears known about their floras. 



It is quite apparent that the whole subject is still involved in the 

 utmost obscurity, and that our actual definite knowledge of Cretaceous 

 Dicotyledons practically amounts to very little. A man would 

 indeed be bold who ventured to pronounce upon the precise age of 

 any Cretaceous rock only from the character of the dicotyledonous 



DECADE in. VOL. IV. KO. IV. 11 



