S 
headland with precipitous cliffs interrupts the continuity 
of the boulder beach, and where the land dips down to the 
Sound the cliffs give way in places to inlets and small bays 
offering a variety of algal habitats with floras of varied 
character. Perwick Bay shelters a stone-covered beach, 
and offers a favourable locality for the study of continuous 
Fucoid vegetation. 
From the point of view of the algologist, however, the 
most interesting piece of coast in the area is that starting 
from Perwick Bay, passing through Port St. Mary Bay 
(Map IJ, ro), Bay ny Carricky (Map II, 11), Pooyllvaaish 
(Map II, 12) and following the contours of the coast round 
Scarlet Point (Map II, 13) as far as the entry of the Silver 
Burn into the sea at Castletown (Map II, 14). 
The tilt of the land is such that the cliffs at Castle- 
_ town give way gradually to an almost flat coastline. The 
diminishing steepness results in a gradually extending 
breadth of shore between tide marks. Much of this piece 
of coast lies on limestone, and is built up of low terraces 
almost horizontal in places and with synclinal and anti- 
clinal slopes dipping gently seaward. These limestone 
terraces offer a type of habitat which stands in sharp 
contrast to the Fucus-covered boulders of the south-west 
coast. In places the limestone is worn into a series of 
hummocks separated by shallow saucer-shaped pools. 
Here is a locality unfavourable to the development of 
fucoid vegetation, but one that provides the student with 
an excellent opportunity of studying the flora of rock 
pools, especially the type known, on account of the 
dominance of Lithophyllum and Corallina, as “ coralline ”’ 
pools. 
The rest of the south-east seaboard is made up of 
stretches of fissured rock, interrupted by patches of sand or 
of sand overlaid by stones. The general trend of the coast 
brings it almost parallel to the direction of the prevailing 
