AND ADJACENT WATERS. 287 



tliese were known to occur in the Sound in Boswarva's time. I sliall 

 suppose readers of the following pages to be familiar with the above- 

 mentioned catalogue, and to have a general knowledge of the Sound, 

 from' the Admiralty chart or otherwise. My chief objects when 

 dredging' were to see if the rare " washed ashore '•" weeds had any 

 local habitat, if there was a well-marked connection between the 

 east and west shores of the Sound by extra-tidal weeds, and to work 

 out as fully as possible the extra-tidal flora. For the accomplish- 

 ment of these objects it was necessai'y to work as near in to the 

 shore as it was safe'^ to take the steamer {" Firefly ") or the sailing 

 boat ("Mabel''). 



Disturbing Influences in the Flora. 



Many disturbing influences have been at work since the date of 

 Boswarva's catalogue, the weeds mentioned by him as occurring in 

 particular localities being in many cases no longer to be met with, or 

 only after very diligent search. Of these influences it will be well 

 to notice a few. 



The Breakwater. — This immense structure, completed in 1841, and 

 extending for more than a mile across the Sound, must have had an 

 impoverishing effect on the flora of the Sound internal to it. This 

 is more especially seen in the eastern inlets. Rum Bay, Jennycliffe 

 Bay, Batten Bay, protected by the Breakwater from the south-west 

 gales, are also cut off, to a large degree, from communication in a 

 south-west direction with the English Channel and the Atlantic 

 Ocean, and, to this extent, deprived of the spores of weeds brought 

 by south-west currents. Batten Bay has been still further denuded 

 by the presence, since 1882, of Batten Pier, and, spite of the pre- 

 sence of several rare weeds, has changed from a locality rich in sea- 

 weeds to one of the poorest, the effects of town and harbour refuse 

 on the seaweeds in these eastei'n bays being also very marked. 



Refuse. — No doubt in the Sound, as elsewhere, the increase, with 

 population, of refuse has had a deteriorating effect on the algse, as 

 e.g. in Batten Bay just cited. I was given to understand that 

 during recent years the bed of the Laira has been raised five feet 

 by the deposit of clay and general refuse from the china clay 

 works on Dartmoor. This cannot but have an effect on the weeds 

 of the Laira and the Cattewater. Batten Pier seems to tend to- 

 di'ive the water from the Cattewater, Laira, and Sutton Pool, west- 

 ward, where, between the west end of Batten Pier and the ladies' 



* I have much pleasure in acknowledgiug the great help I received from the fisherman 

 to the Laboratory, W. Roach, without whose astonishing knowledge of the submerged 

 rocks, &c., it would have been impossible for me to do as I did. 



