230 me. a. c. seward on the [May 1903, 



Conclusion. 



The main object of this paper is to record the occurrence in the 

 Jurassic plant-beds of Yorkshire of a genus previously supposed 

 to be confined to Japan, India, and Bornholm. A comparison of 

 the Lower Jurassic flora from the Eajmahal Series of India with 

 European floras reveals a greater similarity between the vegetation 

 of Eastern and Western regions during part, at least, of the IVIesozoic 

 Era than is usually admitted. The differences between Mesozoic 

 floras of approximately the same geological age are for the most 

 part few and unimportant, when we consider their wide geographical 

 separation. 



Equisetaceous plants are practically ubiquitous ; several ferns of 

 apparently the same species occur in the far East and in Western 

 Europe ; Cycadaceous plants are represented by cosmopolitan types, 

 and the same may be said of the genus Araucarites and other 

 members of the Coniferae. The most noteworthy exceptions are 

 afforded by the Mesozoic representatives of the two isolated recent 

 ferns Matonia 1 and Dipteris 2 ; these two families — each with a 

 surviving genus — played a conspicuous part in the vegetation of 

 the Rhaetic and succeeding Jurassic periods in Europe and, to a less 

 extent, in North America, but we have no satisfactorj?' records of 

 their existence in India or Japan. A similar state of things is 

 illustrated by the Ginkgoales, the class of which the maidenhair 

 tree of China and Japan (Ginkgo biloba 3 ) forms the solitary 

 survivor ; the abundance of both Ginkgo and Baiera in Europe is 

 in striking contrast to their almost complete absence in India. 



Bibliography. 



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