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rocks in the Ural mountains and from Lower Permian 

 beds in France, and those of the recent species, is 

 considered by some authors sufficiently striking to 

 justify the reference of these fossils to tlie genus 

 Ginkgo. Similar leaves of Permian age, which may 

 also be related to the existing species, have been 

 described under the name Ginkgophyllum. Other 

 specimens of Palaeozoic age from North America 

 and elsewhere have been assigned to the Ginkgoales ; 

 but in none of these cases, despite the resemblance 

 in leaf-form, is there sufficiently convincing evidence 

 of close relationship to warrant a definite assertion 

 that the plants in question were members of the 

 group of which Ginkgo alone remains. 



It is, however, an undoubted fact that the INIaiden 

 Hair tree is connected by a long line of ancestors 

 with the earliest phase of the Mesozoic era. From 

 many parts of the world large collections of fossil 

 plants have been obtained from strata referred to 

 the Rhaetic period, or to the upper division of the 

 Triassic system. A comparison of floras from these 

 geological horizons in different parts of the world 

 points to a vegetation extending from Australia, 

 Cape Colony, and South America, to Tonkin, the south 

 of Sweden and North America, which Avas character- 

 ised by a greater uniformity than is shown by widely 

 separated floras at the present day. One of the com- 

 monest genera in Rhaetic floras is that known as 



