4o8 MORPHOLOGY OF GYMNOSPERMS 



^ <» d O" w <l 



~Rt,ctrit 

 \S00mi. 



. mOnii 



TroTirozoio 

 Orcheozofc 



460 



Figs. 459, 460. — Diagrams indicating the historical con- 

 nections of the gymnospenn groups and, the relative periods of 

 time involved : fig. 459, a sector of the earth, showing to scale 

 the thickness of the superficial deposits (shadql)"'from which 

 fossil records have been obtained; fig. 460, the suggested 

 historical connections of the gymnosperm groups, all contained 

 within the shaded region of fig. 459. — Prepared by Sister 

 Helen Angela. y 



459 



