exposed crevices* In some cases they undoubtedly Jiave the 
way for higher plants. Further Inshore various foliose and 
fruticose lichens and mat-forming mosses form a definite 
stage of the rock succession. Among these may be mentioned 
Grimmia apocarpa (I.) Hedw., Amblystegium varium (Kedw.) 
Lindb., Btiota amplissima (Scop.) Mass*, Panne li a conspersa 
(Ehrh.) Ach., StereE7caul on paschale (L.) Hoffta. and various, 
species of Cladonia, 
Following the mosses and lichens one often finds the 
bearberry ( arotostaphylos Uva-ursi fL*) Spreng,) as a pioneer 
mat former. With the accumulation of more soil, shrubby 
species become more abundant. Besides those mentioned, the 
following occur:- Diorvilla Ionicera Mill, (bush honeysuckle), 
Amelanohier canadensis fL.) Medic, (shad bush), Oornus alter - 
nifolia L. f. and Rub us parviflorus IJutt. (salmon berry). 
In the development of this succession finally come 
the trees, their roots sometime spreading 3 - 10 m. before 
finding.a suitable crevice for anchorage (fig. 19). Roots 
of this kind.form an important barrier for holding back soil 
washed from above. The fallen trunks also assist in the same 
manner, as well as finally furnishing additional humus by 
their decay. 
-Types of shere- 
The character of the shore vegetation is largely in- 
