26 ipostelsia 



small dry crevices of the slate rock, and in spite 

 of the ])recari()us foothold flourish better than 

 fartlier l)ack where competition with other forms 

 is more sharp. 



b. Protected rocky beaches. 



These are of two ])rincipal kinds. First, 

 those protected by elevation and distance from 

 the sea and second, those i^rotected by project- 

 ing:; points or shelxes of rocks. The former is 

 characterized bv a more or less scantv depos- 

 ition of soil towards the front and by well estab- 

 lislied lurf towards the l)ack. ()n the patches 

 of soil and in the crevices where soil has ac- 

 cumulated is found a i^rouj) of ])lants which may 

 well Ije desiL^nated as a society of rock peren- 

 nials. The species abounding here are:- 

 Paiiiriiiii unci pliylluni Frai^aria chUocusis 



Deschampsia cacspitosa Trijoliiim heterodon 



AUium ccrniium Prunella vulgaris 



Riniicx salicijolius Castilleja acuminata 



Sagina occiilciitalis Achillea lanulosa 



Aster joliaceiis 



This association is succeeded in passing to- 



