204 F. H. KNOWLTON 



Jabalpur 

 China Tyrkyp-Tag 



Border Hami Desert 

 Australia 

 New Zealand 

 Louis Philippe Land 63° S. 



The flora of the Jurassic, while in the main a continuation of that 

 of the late Trias, and consisting of equisetums, ferns, cycads, ginkgos, 

 and conifers, shows the incoming of a number of more modern types 

 in these groups. The cycads were of course abundant and diversified, 

 whence it has been called the age of cycads. The flora is remarkably 

 uniform over wide portions of the world. Thus not far from 50 per 

 cent, of the North American flora — exclusive of the cycad trunks — 

 is the same as that found in Japan, Manchuria, Siberia, Spitzbergen, 

 Scandinavia, or England, and what is even more remarkable, the 

 plants found in Louis Philippe Land, 63° S., are practically the same 

 as those from Yorkshire, England. 



Some idea of the climatic conditions which prevailed at this time 

 may be gained from the present distribution of certain obvious 

 descendants of the Jurassic flora. Thus Matonidium and Laccop- 

 teris are represented by Matonia of which there are two species living 

 in the Malay region and Borneo; Dictyophyllum, Protorhipis, Haus- 

 mannia, Caulopteris, etc., are closely allied to Dipteris, which has 

 five species living in the eastern tropics; Ginkgo — so abundant in 

 the Jurassic — has but a single living representative in China and 

 Japan. 



Climatic conditions in Jurassic. — The presence of luxuriant ferns, 

 many of them tree-ferns, equisetums of large size, conifers, the 



