438 TEANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



provided with a flap which was intended to prevent the 

 escape of sewage at other than ebb tide. This flap, so I 

 was told, became detached some years ago, and in addition 

 a number of pipes have worked loose, become unbolted or 

 broken, so the sewage now escapes at all states of the tide, 

 and at a point some 40 feet nearer shore than the point 

 marked by the buoy. I also heard that one of the pipes 

 had even been standing on end, and had to be removed, as 

 it was a danger to navigation. I should, therefore, have 

 dropped my floats 40-50 feet closer inshore, but this was 

 impossible owing to the danger of the launch going 

 aground. The results obtained on ebb tides showed that 

 at neaps the sewage does not get carried down to the bar, 

 but is held in the eddy off Ynys-y-Brawd, moving up and 

 down between the island and the sewer outfall till turn of 

 tide. The sewage at such periods can be seen at the sur- 

 face in the area marked, and also lying about the shore of 

 the island near the beacon. At spring tides the floats were 

 carried down towards the bar and out to sea. 



A lavatory with three privies on the quayside is 

 another contaminating influence in this area, which dries 

 out completely at low tide. Any sewage entering here 

 is likely to accumulate, and probably only gets carried 

 away by a strong flood tide. On flood tides the direction 

 taken by the floats after reaching the railway bridge 

 depends on the state of tide and the amount of water in 

 the estuary. The earlier the state of tide the closer inshore 

 is the drift likely to be. At no state of the tide though 

 did the floats pass directly over the mussel beds between 

 the bridge and Aberamffra harbour. Considering the 

 distance of these beds from the sewer outfall it seems pro- 

 bable that a good deal of the contamination of these 

 mussels is due to the drains from the houses on the cliff 

 which empty directly on to the beds. Here, too, at low 



