264 Miocene of Midi and Arctic Regions. 



being diminished by central subsidence and long-con- 

 tinued sub-aerial waste, the mountain of Beinn More in 

 Mull is now only 3,172 feet in height. 



No shells of any kind have yet been found in the 

 Bovey beds, nor have any been seen in the Hebrides, but 

 in Mull, at the headland of Ardtun, the Duke of Argyll 

 discovered in 1851 three thin leaf-bearing beds of 

 shale, intercalated among beds of basaltic lava, and 

 tufas or volcanic ashes. These vegetable remains con- 

 sist of a conifer, Sequoia Langsdorfii, together with 

 Corylus Mac Quarrii, a plane tree, Platanus aceroides, 

 and a fern, Filicites hebridica, as yet only found in Mull. 

 These, and I believe also the Flora of Antrim, are partly 

 considered to belong to a more northern type of vegeta- 

 tion than the plants of Bovey Tracey, and two of the 

 species, the Coryllus and Platanus, are also found in 

 Iceland. 



Associated with the volcanic rocks of Skye and 

 the Faroe Islands, similar phenomena occur, with an 

 analogous but still more northern flora, and the early 

 volcanic eruptions of Iceland date back to the Miocene 

 period. There, in beds of lignite called Surturbrand, 

 are found the remains of Pines, Poplars, Elms, Plane- 

 trees, Maples, Oaks, Tulip-trees, and Vines, in latitudes 

 where nothing larger than dwarf-birches now grows. 

 Only two of the Iceland species, as stated above, occur in 

 Britain, and even the genera are distinct from those of 

 Bovey, with the exception of Sequoia and an Oak. In 

 Spitzbergen a similar flora of Miocene age occurs, and 

 also in Greenland, far north of the Arctic Circle. 



It may seem remarkable that, within the broad area 

 of the British Islands, no mammalian remains have been 

 found in the Miocene strata, for surely a land covered 

 with a wealth of trees, grasses, and other plants could 





