. Fossil plants : for students of botany and geology . Paleobotany. XL] GINKGOITES 19. occasionally occur iu association with the foUage of this and otbe; Jurassic species. Male flowers^ similar in habit to those of Ginkgo bildba are also found in beds containing impressions of Ginkgoites. The abundance and wide geographical range of Ginkgoites digitata precludes anything more than a brief reference to some representative types selected in illustration of the range in form and the widespread occurrence of the species in Jurassic floras. The leaf represented in fig. 637 is an unusually complete
. Fossil plants : for students of botany and geology . Paleobotany. XL] GINKGOITES 19. occasionally occur iu association with the foUage of this and otbe; Jurassic species. Male flowers^ similar in habit to those of Ginkgo bildba are also found in beds containing impressions of Ginkgoites. The abundance and wide geographical range of Ginkgoites digitata precludes anything more than a brief reference to some representative types selected in illustration of the range in form and the widespread occurrence of the species in Jurassic floras. The leaf represented in fig. 637 is an unusually complete example from the Middle Jurassic beds of Scarborough; the lamina is 3-8 cm. deep and 6 cm. broad, the venation agrees with that of Ginkgo hiloba. A very similar type of leaf is figured by Heer from Upper Jurassic (or Wealden) strata of Spitzbergen as G. integriuscula^, but with the proviso that it may be merely a variety of G. digitata, a view that Nathorst^ has wisely adopted. The latter author in spealdng of the occurrence of G. digitata in Spitzbergen states that 'sometimes the surface of the schists [shales] is as completely covered with the leaves of Ginkgo as the soil beneath a living Ginkgo tree may be in autumn*.' In some specimens from the Yorkshire coast the lamina is practically entire as in a leaf from Scarborough in the York Museum figured in 1900^. An exceptionally large form is shown in fig. 638; the lamina, 8 cm. broad, is divided into several short and comparatively broad obtuse or truncate lobes*. Fig. 639 shows a leaf from the Stonesfield Slate, now in the Cirencester Museum; the lamina is deeply divided into two broad cuneate lobes as in some forms of the recent species. The Stonesfield Slate specimens were origin- ally named by Buckman Noeggerathia {1) and later Stricklandia 1 See page 51. 2 geer (77) i. p. 44, PI. x. figs. 7—9. ' Nathorst (97) p. ; for a discussion of the age of the Spitsbergen beds, see JSTathorst (IS^). « Nathorst (11') p. 221. °
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