Clare Island Survey — Marine Algae. 15 11 



Man}' of the islands provide flat beaches of sand and stone with good 

 collecting-ground at low water. At Armagh Island there is a salt-marsh. 

 The Bunowen river at Louisburgh, the stream at Belclare, and the rivers 

 at Westport and Newport give brackish and fresh-water conditions. In 

 the innermost part of the bay there are wide stretches of mud, and the 

 ground is very poor ; with the exception of hasty inspections near Westport 

 and one day at Newport, it was but little explored. The northern side 

 consists largely of sand. At Mulranny there are strips of salt-marsh, 

 also fresh-water and brackish streams. The peninsula of Curraun 

 Achill follows, with a rocky shore of Old Eed Sandstone and exposed 

 conditions. 



The floor of Clew Bay is everywhere soft, consisting of sand with stones. 

 In spring and early summer there is a rich and luxuriant sub-littoral vegeta- 

 tion, which in shallower parts may be easily studied from a boat, or hauled up 

 by a hand-dredge. Banks of Lithothamnium occur, and there are numerous 

 Zostera beds. Between the outer islands, channels with a swift current, where 

 the bottom is usually stony, are frequent. 



Achill Sound, easily reached by train from Mulranny, provides perfect 

 shelter, and yet fully saline conditions. At low water, the Sound becomes 

 dry, exposing a large stretch of sand. The water enters from both the north 

 and south, and at the end of the ebb-tide the parting of the streams will be 

 observed to take place at a point about a quarter of a mile south of Achill 

 Bridge. The vegetation is for the most part poor, especially in the summer ; 

 but channels provide good ground, and the stones set out by the peasants 

 yield a fine crop of Fucus. Further south (towards Achillbeg) there are 

 swift currents and deeper water, and here a marked increase in the 

 luxuriance of the vegetation is noticeable. On the north side of the bridge 

 there is much mud ; but the peat banks flooded by the tide offer some in- 

 teresting types of plant-associations. Bellacragher Bay, a lough-like inlet 

 surrounded by high hills, differs from Achill Sound in possessing deep water, 

 and being less tidal. It is connected with the sea (Blacksod Bay) by a 

 narrow opening at the north-west corner. Several streams descend from the 

 hills ; and owing to the water only partly escaping on the ebb, the whole 

 bay must be often more or less brackish. Some samples taken at the end 

 of the dry summer of 1911 showed, however, almost normal salinity. The 

 littoral region is narrow, and composed of stones or rock. The bottom 

 appears to be rocky, since a vigorous belt of Laminaria is disclosed at low 

 water. 



B2 



