30 GmKGOALBS [CH. 



name Salisburia adiantoides for the Miocene leaves from Sengallia 

 in North Italy Unger^ indicated their pfobable identity with 

 Ginkgo biloba L., the generally adopted name for the existing 

 species which Smith in 1797 proposed should be called Salisburia 

 adiantifolia^. The Miocene leaves from SengaUia figured by 

 Massalongo and Scarabelh^ have an entire, irregularly crenulate 

 or a more or less deeply bilobed lamina very Uke that of Ginkgo 

 biloba: the specimen named by them S. Procaccini* should also 

 be included in G. adiantoides. The resemblance to the recent 

 leaves extends to the presence of short secretorj^ tracts between 

 the veins, but these were referred by Massalongo to a fungus 

 which he named Sclerotites Salisburiae^ . 



The two specimens reproduced in fig. 644 from the Eocene beds 

 in the Isle of Mull illustrate the broad fan-hke lamina that varies 

 from 5 to 10 cm. in breadth and may be entire, unevenly lobed or 

 symmetrically bilobed. The venation is identical with that of the 

 living species : the characteristic marginal veins on the lower edge 

 of the lamina are clearly seen in fig. 644, A. The preservation 

 of these British leaves described by Mr Starkie Gardner^ is 

 exceptionally good; they occur as purple impressions in white 

 clay interbedded with basaltic sheets in the chfEs of Ardtun Head 

 in the Island of Mull. Though perhaps on the average these 

 Eocene leaves from Mull are larger than those of the Maidenhair 

 tree some examples of the latter exceed in size any of the fossils. 



Leaves identical with or very similar to the Itahan and Scottish 

 specimens are recorded from both Tertiary and Upper Cretaceous 

 rocks in many parts of the world. Specimens collected by Dr Lyall 

 from Tertiary (Miocene or Eocene) beds on Disco Island off the 

 West coast of Greenland, lat. N. 70°, were described by Heer' as 

 Salisburia borealis and he also speaks of them as Salisburia adian- 

 toides var. borealis^. An examination of the original specimens 

 in the Kew Museum and an impression in the Dublin Museum 



1 Unger (45) p. 211 ; (50) A. p. 392. = Smith, J E. (1797). 

 3 Massalongo and ScarabeUi (58) p. 163, PI. i. fig. 1 ; PI vi fie 18 • PI vii 

 fig. 2 ; PI. XXXIX. fig. 12. = . . 5. , . . 



» Ibid. p. 165, PI, XXXIX. fig. 1. 



'■ Ibid. PI. I. fig. la. ■ c Gardner (86) p. 99, PI. xxi. ; (87) A. 



' Heer (68) i. p. 95, PI. 11. fig. 1 ; Pl. xLvn. fig. 4 a . 



" Ibid. p. 183. 



