20 Postelsia 
cases the distance from the waters edge to the 
forest is generally considerable and the gently 
sloping beaches are mostly bare in front but 
loaded with driftwood towards the back. If 
the inlet is sheltered from the wind, the sand 
beach is of less width, and driftwood is either 
absent or found only in small quantities. Other 
inlets are narrow and are simply openings of 
small ravines or gullies. These are drainage 
courses and frequently small streams find their 
way through them to the sea. From the fact 
that these streams drain from the humus-laden 
forest soil, a greater complexity of plant life is 
met with upon the sand beaches at the mouth of 
these ravines than upon other kinds referred to 
above. ‘The humus contents of the soil is much 
greater than that of the larger, more open 
beaches, backed by no extensive natural drainage 
course. It is quite evident that conditions 
arising landward exert themselves more strongly 
here because they are concentrated as it were, 
into a smaller space. The result is the establish- 
ment of a group of plants numerous both as to 
individuals and species and among which the 
competition is sharp. 
