1914-15.] BOTANICAL SOCIETY OF EDINBURGH 351 



A. Findhorn Bay Margin — 



1. Salt-Marshes. 



2. Fixed Dunes, adjoining on the west the Salt- 



Marshes, and in several places passing into and 

 combining with them. 

 i". i Sandy Flats. 

 Sandy Rid^. - 



B. Culbin Sandhills proper — 



1. Shifting Dunes. 



2. Fixed Dunes. 



3. Dune-Marshes. 



C. Maviston Sandhills — 



1. Fixed Dunes. 



2. Shifting Dunes. 



A. Findhorn Bat Margin. 



The road which gives most convenient access to the 

 Culbins enters at the south-west corner of Findhorn Bay 

 and continues in a northerly and north-easterly direction 

 through the sand, along the flat which is bounded on the 

 east by Findhorn Bay. on the west by a ridge of fixed 

 dune and the north end of the birch wood, until it leaves 

 the sands again at Binsness Wood. The flora of these flats 

 and the ridges which are properly included in the same 

 division, owes its striking combination of salt-marsh and 

 fixed-dune characters to the fact that, while the region 

 lies to leeward of the shifting dunes and, in one sen- 

 landward of the seashore from the direction of which the 

 prevailing westerly winds carry the sand, it at the same 

 time is close beside the tidal waters of Findhorn Bay. 

 Thus, on one side are found purely sand-dune associations, 

 where the substratum of sand is blown in from the shifting 

 dunes ; on the other are salt-marsh plants where the muddy 

 soil is washed by the estuarine water. Further, although 

 one may conceive a sort of normal boundary where these 

 two influences meet, instability and a mixed character are 

 given to the associations by the blowing of sand in excep- 

 tionally high winds on to the salt-marsh, in places resulting 

 in the growth of sand-plants above buried marsh-plants. 

 and by the flooding of the sandy areas in high tides with 

 resultant changes in the soil and the vegetation. 



