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volcanic activity which characterised the north-west 

 European area in the early Tertiary period and resulted 

 in the formation of the thick sheets of basalt on the 

 north-east coast of Ireland and in the Inner Hebrides. 

 There were occasional pauses in the volcanic activity, 

 during which vegetation established itself on the 

 wreath ered surface of the lava, and left traces of its 

 existence in the leaves and twigs preserved in the 

 sedimentary material enclosed between successive 

 lava-floras. xVt Ardtun Head in the Isle of Mull 

 beautifully preserved leaves of Ginkgo, 2 — 4 inches 

 in breadth, with the median sinus and the venation 

 characteristic of the leaves of the existing plant, have 

 been discovered in a bed of clay which marks the site 

 of a lake in a depression on the lava-plateau. The 

 resemblance of these Tertiary leaves fi-om Mull to 

 those of the surviving Maiden Hair tree is so close as 

 to suggest specific identity. Mr Starkie Gardner and 

 Baron Ettingshausen have described some seeds from 

 the London clay (Lower Tertiary) in the Isleof Sheppey 

 as those of Ginkgo, but this identification rests on 

 data too insufficient to be accepted without hesitation. 

 The recent cultivation of Ginkgo hiloha in Britain 

 may therefore be spoken of as the re-introduction of 

 a plant which in the earlier part or in the middle of 

 the Tertiary period flourished in the west of Scotland, 

 and was abundant in England in the earlier Jurassic 

 period. It is impossible to say with any confidence 

 where the Ginkgoales first made their appearance. 



