=> ~ We 
Photo by W. L. Bra 
od 
y. 
Iie. 23. Large angular boulder, Heel Pond, with moisture-holding blanket 
built up by vegetation, and now covered by polypody. 
Photo by W. L. Bray. 
Fig. 24. A boulder upon which the soil blanket became heavy enough to 
support approximately climax forest vegetation. 
