22 GINKGOALES [CH, 



digitata and the veins are more crowded. For this type I suggest 

 the designation G. digitata var. polaris. Solms-Laubach 1 figures 

 an incomplete leaf from Franz Josef Land with a broader lamina 

 divided into several broadly rounded segments as in many British 

 specimens but with rather closer venation. A similar leaf from 

 the same locality is figured by Newton and Teall 2 . Fig. 635, K 

 shows a lobed leaf similar to that represented in fig. 640, described 

 by Nathorst 3 from Franz Josef Land and compared by him with 

 G. sibirica Heer and G. flabellata Heer from the Jurassic of East 

 Siberia. A very small specimen similar in form to the larger 

 example shown in fig. 635, K was figured by Nathorst 4 , also from 

 Franz Josef Land, as Ginkgo polaris var. pygmaea. From the 

 west coast of Greenland Hartz described a leaf very similar to 

 some of the Yorkshire examples as Ginkgo (Baiera) Hernielini 5 : 

 Hartz regarded the beds as Liassic or Rhaetic, and the occurrence 

 of shells pointing to a Kellaways horizon immediately above the 

 plant-beds suggests that the latter may belong to the Middle 

 Jurassic series 6 . Ginkgo digitata is represented also in Jurassic 

 strata in the New Siberian Islands by a leaf figured by Nathorst 

 as Ginkgo sp. which agrees with the type G. digitata var. Huttoni 7 , 

 and Krystofovic 8 has described G. digitata from Jurassic beds in 

 Ussuriland at the northern end of the Muravjev-Amurskyj penin- 

 sula. Some good specimens are recorded from Bornholm 9 , oi 

 Middle or Lower Jurassic age, as G. Huttoni which are identical 

 in form and size with British specimens. 



North America. 





Several examples of leaves of the G. digitata type and some of 

 the form Huttoni have been figured from Middle Jurassic rocks 

 irr Oregon 10 (fig. 635, H). Some particularly large examples are 

 named by Fontaine G. Huttoni var. magnifolia but these are not 



1 Solms-Laubach (04) PL i. fig. 10. 



2 Newton and Teall (97) PL XLI. fig. 10. 



3 Nathorst (99) p. 11, PL i. figs. 819. 4 Ibid. PL T. figs. 20 ? 21. 

 5 Hartz (96) PL xix. fig. 1. 6 Johnstrup (83). 



7 Nathorst (07) PL i. fig. 20. 



8 Krystofovic (10) PL m. fig. 1. 



9 Bartholin (94) p. 96, PL xn. figs. 13; (10) PL m. figs. 9, 10. 

 10 Fontaine in Ward (05) B. Pis. xxx. xxxn., XLVI. 



