450 ANNUAL REPORT SMITHSONIAN INSTITUTION, 19 3 8 



of Siberia and as far east as the western shores of the Pacific Ocean. 

 Its territory was spread over wide tracts in both the Old and the New 

 World, mainly in the Northern Hemisphere. It is, however, sig- 

 nificant that in 1935 Prof. E. W. Berry, of Johns Hopkins University, 

 recorded the discovery of Tertiary Ginkgo leaves in Patagonia. This 

 fact affords impressive proof of the enormous distance over which 

 Ginkgo trees had been dispersed. Tertiary records are not all from 

 rocks of the same geological age; most of them are from the Lower 

 Tertiary, the Eocene stage; some from Miocene and Oligocene rocks 

 and a smaller number from the uppermost, or Pliocene stage, of the 

 period. As the ages of the Tertiary period passed, the geographical 

 range of the genus became more restricted until, so far as we know, 

 only a single species remained when the Recent period began. 



There is no clearly marked difference in the position occupied by 

 the genus in the living garment of the Cretaceous earth; it was very 

 abundant as far back as the older Cretaceous floras. The chief 

 difference is that as we descend from the Tertiary to older periods we 

 find a gradual increase in the number of other genera of the Ginkgo 

 family. Confining attention for the moment to Ginkgo, it is interest- 

 ing to find in rocks corresponding in age to the sediments deposited 

 in the great Wealden lake of southern England, northern France, 

 Belgium, and northern Germany leaves very similar in external 

 characters to those of the maidenhair tree. Such have been dis- 

 covered in Lower Cretaceous strata in Alaska, western Greenland, 

 Franz Josef Land, northwest Germany, northern France, and else- 

 where. Fossils gathered from the sedimentary beds of the still more 

 ancient Jurassic period at many localities in both hemispheres demon- 

 strate an almost world-wide distribution of Ginkgo. Some of the 

 leaves from the Jurassic rocks near Scarborough bear a striking re- 

 semblance in size, shape, and venation to the modern type of foliage 

 and differ only in comparatively minor structural characters. With- 

 out discussing precise correlation of plant-bearing beds within the 

 long period embraced by the Jurassic system with its several subdivi- 

 sions, it can be said with confidence that Ginkgo had by that time 

 reached its maximum in abundance and geographical range. There 

 were Ginkgo trees in Jurassic Australia, New Zealand, Afghanistan, 

 Turkestan, Siberia, many parts of China, also in Japan and Korea. 

 It grew in southern Russia, in Sardinia, and throughout Europe; it 

 had wandered as far west as Oregon on the Pacific coast. A few 

 specimens from Jurassic rocks of India have been assigned to Ginkgo, 

 but these are less satisfactory as records than those from other regions. 

 It is noteworthy that neither Ginkgo nor any other member of the 

 family has been found in the rich Jurassic flora described some years 

 ago from Grahamland, which members of the recent Grahamland 

 expedition have proved to be a peninsula of the Antarctic continent 



