SEED-BEARING PLANTS 



425 



Fig, 315. — The organization of shallow water accumulations in a lake 

 of the present geological epoch, showing remains of roots, leaves, etc. 

 Near the center of the figure may be seen a cross-section of the triangular 

 needle of a white pine. (Cf. Figs. 316 and 317.) (After E. C. Jeffrey.) 







Fig. 316. — Fine muck from the bottom of a pond, as seen under the 

 compound microscope, showing the presence of pollen grains of pine, 

 spruce, and fir. (Cf. Figs. 315 and 317.) (y^.fter E. C. Jeffrey.) 



