Inter-tidal Zonation — BEVERIDGE and Chapman 
199 
Fig. 11. Vertical distribution of species of the 
northeast and north of Lion Rock. 
different adjustment. The chief guide used in 
making this adjustment was the level of the 
species in the most sheltered habitats. It 
must, however, be emphasised that owing to 
the great difficulties involved this attempt at 
allowing for wave action can only be a first 
approximation. From a study of this diagram 
it may be concluded that the most marked 
critical levels (i.e., levels where a number of 
species reach their upper or lower limit) are 
as follows: 
Upper Lower 
limits limits Total 
11 feet— M.H.W.S. . . 6 3 9 
Between 8.5 and 9.5 feet 3 3 6 
4 feet— E.(H).L.W.N. .5 2 7 
3 feet— M.L.W.N. . . 5 1 6 
2.3 feet 4 3 7 
1.4 feet— M.L.W.S. . . 5 4 9 
It will be seen that there are nine upper or 
lower limits between 11 feet and M.H.W.S. 
so that this, together with 1.4 feet, is one of 
the more distinctive levels. Reference to Fig- 
BY TIDE POLE N. CAMEL ROCK 
north of Camel Rock. 
