168 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



any pollution of the smaller channels on the north side of the 

 estuary since there are only a few houses here and there along 

 this shore. 



The main sources of pollution of the estuary are Lancaster 

 and Stodday, that is, a population of over 40,000 persons. 

 All this sewage is untreated. It enters the channel at various 

 points higher up than the area represented on the Sketch 

 Chart. Two sewers are shown, those at Glasson and Conder 

 Green. These serve a population of about 1,600 persons. 

 The sewage is untreated and discharges directly into the sea, 

 the Glasson sewer into the main channel, and the Conder 

 Green sewer into a brook which flows through a salt marsh 

 into the main channel. 



The mussels taken from the Lune Estuary come from 

 various places. Most are taken from the training wall at 

 Bazil Point and the adjacent part of the channel. This wall 

 is a rubble structure which comes adry at low water, so that 

 it is washed by the water coming down the channel at the 

 lowest states of the tide. The mussels here are thoroughly 

 polluted. The numbers M 90,000, 11,650, and 3,700 represent 

 the results of recent analyses — they are the mean numbers of 

 sewage bacteria contained in a mussel. Some mussels are 

 taken from Crook Skear, which is the area of rough foreshore 

 opposite Sunderland Point. Others are taken from the Skears 

 at Abbey Lighthouse, and from the bottom of the Channel 

 near there. 



The water in the estuary at low water is greatly polluted. 

 The numbers W 83 and W 82 on the sketch chart represent 

 the numbers of sewage bacteria per cubic centimetre as found 

 in some recent analyses. These numbers would probably vary 

 greatly from time to time according to the state of tide and 

 the amount of fresh water in the river. 



In the cleansing experiments the mussels were taken from 

 the training wall, and the adjacent bottom of the channel not 



