AND GKAVELS Of AKDTUN, ETC., IN MULL. 



295 



opinion regarding the age of any of the older Tertiary floras, even 

 with the best of material. 



There are, moreover, many prevailing types of leaves common to 

 widely distinct genera which seem to occur in- most floras, whether 

 recent or fossil. The so-called Corylus, on which so much stress 

 has been laid, is one of such ; for even the brambles and hazels in 

 any hedgerow are seen to have the same cutting and venation. 

 The identifications of the Mull and Greenland plants with those of 

 European Miocenes will be seen to rest upon leaves of this kind, 

 and not upon the well-characterized forms, which differ most com- 

 pletely. Instances of similarity, and even identity, between the 

 Greenland plants in question and those of the Cretaceous and older 

 Tertiary floras of Europe have passed without comment, whilst the 

 majority of the identifications actually made are untrustworthy, for 

 in nearly every case there are marked and often fundamental dis- 

 crepancies between the form and venation of the leaves compared. 



Of the Eerns, the oldest are unknown in any other European 

 formation, though the Ballypalady type appears in the ' Heersien ' 

 of Gelinden and the Woolwich Beds of Bromley ; but directly the 

 newer beds of Lough Neagh are reached two widely spread Middle 

 Eocene types appear (Journ. Linn. Soc, Bot. vol. xxi. pi. xxvi.). Of 

 the Conifers, the only one to reappear in any post-Eocene deposit of 

 Europe is the still living Ginkgo, which recurs in the late Miocene 

 or Pliocene (?) of Sinigaglia, in North Italy. It is upon the Dicoty- 

 ledons, however, that reliance has chiefly been placed ; and it is 

 likely that their evidence is the more trustworthy, since they must 

 have been undergoing somewhat rapid modification in the direction 

 of existing species and genera. 



The first fossil plants brought back by Arctic expeditions were 

 from the lower of the two plant-beds at Atanekerdluk, in Green- 

 land ; and collections from this were made by McClintock, Colomb, 

 and Whymper. They were determined by Heer to be Miocene, and 

 comprised not only all the plants from Ardtun illustrated byEorbes, but 

 most of those since discovered by Baily at Glenarm and Ballypalady, 

 in Antrim. Fifty-two out of the 178 species * from this bed were 

 identified with European or American Miocene plants, and these we 

 propose to examine, since the evidence in support of the Miocene 

 age of the Ardtun plants alone would scarcely require further con- 

 sideration ; whilst if the Atanekerdluk bed is really Miocene, the 

 Ardtun bed would be equally so. The Atanekerdluk bed is 1200 

 feet above the sea, and under a great capping of basalt ; most of the 

 leaves were found in a reddish concretionarv ironstone like that of 

 Lough Neagh ; and others, less distinct, in dark shale and a yellowish 

 ochreous sandstone. A second plant-bed occurs 200 feet above, 

 with considerably more than half its 78 species peculiar to it, and 

 much less like those of Mull and Antrim. Since then fossil plants 



* At least one half of these should be suppressed. Robert Brown, the com- 

 panion of Whymper, was the first naturalist to visit these beds, and he strongly 

 protested- against the " reckless way Heer makes species and genera out of these 

 fossils." Trans. Edinb. Geol. Soc. vol. i. p. 194 (1868). 



