912 ^^- YOKOYAMA; MESOZOIC PLANTS 



ours ; wliil.st in the Dogger flora we have a comparatively rich one 

 from Siberia. 



The determination of the age of the plant-heels leads to the con- 

 clusion that on the outer or convex side of Japan, ns far as our present 

 investigation goes, no Middle Jurassic fresh-water formation is 

 developed. Ijut whether the converse liolds true, that no Younger 

 Mesozoic p]ant-heds have Ijcen deposited on tlie inner or concave side 

 of Japan is at present difficult to say and must be left for future 

 investigation to determine. 



For C(3nYenience' sake I propose tlie name of L'ijüscl^i Sen\'s lor 

 all those strata containini"' Younaer Mesozoic plants in distinction to 

 those containing- Middle Jurassic ones. For the latter I also sufi'^'est 

 the name Tcluri Series, from the ^■alley (jf the river lV't»jri in K:iga, 

 where thev Avere first discovered. 



