THE MARINE ALG.E UF GUKKNSEy 29 



or three inlets. Sand and peb])ly beaches — with great upstanding 

 boulders covered, or forming islets, at high tide,— reefs, platforms, 

 and low-lying rocks, hollowed out into pools or chinks, comprise the 

 main characteristics of the eastern side. 



The south of the Island has two wide bays, within which are 

 creeks running into the cliffs ; this region is well sheltered and the 

 temperature is warmer. Furtlier along, the coast is difficult of access 

 and moderately exposed, for the rocks rise sheer out of the water to a 

 considerable height, but here and there are some narrow openings 

 where the climb down to the boulder-heach, with rocky floors and 

 pools, is steep and difficult. I was only able to examine one of these, 

 Les Thielles. Pleinmont, the extreme south-west corner, is the most 

 exposed part of the Island ; the shores are rocky, very jagged and 

 rough, and boulders of all sizes lie scattered about. The gigantic 

 walls of rock screen off and afford some local shelter. Clefts between 

 descending terraces give passage to runnels and streams, after the 

 tide has receded. There are deep channels, pools, and lanes between 

 the rocks. 



The north-west coast is moderately exposed. Along it are five 

 deep bays, sandy down the centre, but intersected with reefs, and 

 rocky at the extremities. Large patches of Zostera occur low down 

 on the beach. The northern arm of liocquaine Bay is connected 

 at low tide with the Island of Lihou by a causeway ; on either side 

 there is a vast area of sand and pebbles interspersed with rocks, pools, 

 and Zostera beds. This is all covered at high tide and swept by a 

 channel with a strong current. Here and there the rocks half 

 encircle a terraced creek and give exceptional shelter. The wdiole 

 coast from Pleinmont Point to Grandes Hocques is thickly fringed by 

 countless islets, barriers, and reefs of rock, whose jagged and sharply- 

 jutting crags break the huge waves which come rolling up the 

 Channel into an enormous tract of surf and foam. The shores 

 beyond and north of Grandes Eocques are much flatter and mode- 

 rately exposed. There are several small ba^'s with boulder-beaches. 

 The rocks are less high and rough, the whole district lies at a much 

 lower level than the south, the slope of land being from the south to 

 the north downwards. Grande Havre and L'Ancresse are deep and 

 land-locked bays ; the former is a large quiet expanse with sandy 

 beach and scattered masses of rocks. L'Ancresse is so hemmed 

 round hy rocks as to form a locally sheltered district with sharply- 

 descending shores. 



The coasts of Guernsey therefore possess aspects which range from 

 extremely sheltered to quite exposed with the intermediates of mode- 

 rately exposed or locally sheltered. The shores consist of sand, mud, 

 and Zostera beds, with boulders and rocks of varying height and 

 roughness. 



(()) Salinity. 



Owing partly to the smallness of the Island, there are only a few 

 unimportant streams and an absence of any large body of fresh water 

 discharging its contents into the sea. The general luxuriance of the 

 marine vegetation is therefore unchecked by great variations in 

 the degree of salinity, which, in the English Channel, is unusually 



