AND GEAVELS OF AEDTUN, ETC., IN MULL, 



299 



cation of these beds renders it in the highest degree improbable that 

 beds of Eocene age should be unrepresented, whilst the known 

 temperature of the Eocene would have been more favourable to the 

 growth of temperate floras in high latitudes than the diminished 

 heat of the Miocene. If paleeontological evidence is to count for 

 anything, the floras of Glenarm and Ballypalady must be correlated 

 with the Thanet flora of Grelinden ; the lower bed of Atanekerdluk 

 is a little older, and the flora* of Ardtun is a little older still. The 

 relative stratigraphical positions of the Antrim and the Ardtun 

 leaf-beds bear this out. The flora of Lough Neagh, which is the 

 newest of the basaltic floras in Ireland, is, upon palaeontological 

 evidence, somewhere on the horizon of the Bournemouth and Bovey 

 floras. 



I have dwelt at some length on the illusory nature of the evidence 

 upon which these floras have for so long been regarded as Miocene. 

 The misconception as to their age was easy to propagate, but, after 

 finding a place in every text-book of geology for 35 years, is hard 

 to remove. If I have failed to attain this object, I am convinced 

 that it is less from lack of evidence than from failure to arrange 

 it in a convincing manner. Wo steps towards a rational appre- 

 ciation of fossil floras can be made until the fallacies regarding 

 their age are swept away ; but when this shall have been accom- 

 plished, due allowance being made for differences of latitude and 

 longitude, they may even surpass faunas in furnishing trustworthy 

 data for determining the age of rocks. 



EXPLANATION OF THE PLATES. 

 Plate XIII. 



Eocene Plants and Insects from Limestone of Ardtun ; natural size, except 



fig. 14 a. 



Fig. 1. Coniferous foliage, resembling that from Greenland described as Sequoia 

 Langsdorfii, Heer. 



2. Coniferous foliage, similar to that described as Glyptostrobus europaus, 



Heer. 



3. Fruiting branch of Podocarpus borealis, sp. nov. (p. 289). 



4. Flower-spike stem. 



5. 6, 10. Bracts or fragments of husks. 



7. Small drupaceous fruit. 



8. Elytron of a beetle. 



9. Hind wing of a Cercopid insect. 



11. Impression of a large subarjgular seed. 



12. Fruit of Platanus hebridicus, Forbes ? 



13. 14, 15. Male catkins of ditto. 

 14 a. Detached anthers, magnified. 



Plate XIV. 



Typical Eocene Plants from Limestone of Ardtun ; natural size. 



Fig. 1. Lobed leaf, a- form usually ascribed to Acer. 



2. Quercites grcenlandicus, Heer. 



3. Ovate, serrate leaf, undetermined. 



