1914-15.] BOTANICAL SOCIETY OF EDINBURGH 347 



The great storm on the Culbins came with a west wind, 

 and winds from the same direction are said, as above 

 noted, to be still the prevailing. 1 The arrangements of 

 the blown sand and the changes in its position certainly 

 suggest that this is the case. 



Geology. 



The Culbin Sands, according to Craig, rest upon the 25- 

 foot beach which extends from Inverness to the mouth of 

 Findhorn and which is here especially broad, the 100-foot 

 terrace at Kintessock being about 2\ miles from the 

 present coast. 2 



The sand is finely pulverised and free from shells, pebbles, 

 or organic remains. 3 The particles are mostly about j-J^ 

 inch in diameter, according to Mackie, 4 and show a very 

 high degree of rounding. This is due to the fact that 

 the sands owe their form largely to the action of wind. 5 

 The sand shows a preponderance of kaolinised felspars, 

 about 73 per cent. 6 Mackie gives the results of an exami- 

 nation of a specimen of Culbin sand with mineralogical 

 constituents and degrees of rounding. 7 Another examina- 

 tion shows the " inordinate disproportion of the quartz to 

 the felspar and other constituents." Out of 100 particles, 

 78 were quartz, 18 felspar, 1 composite fragment of quartz 

 and felspar, 1 flake of mica, 1 fragment of garnet,! either 

 a particle of magnetite or a chip of hornblende, tourmaline, 

 zircon, or sphene. 8 With regard to the source of the sand, 

 Mackie compares the felspars with those of the Ardclach 

 and Kinsteary granites, 9 and also compares the size of the 

 sand-grains with those of the rivers Findhorn and Nairn, 

 " from which we have reason to believe they have in large 



1 "260 days in the year at Forres "—Craig, The Culbin Sandhills, 

 p. 528. 



2 Craig, The Culbin Sandhills, p. 526. 



3 Ibid., p. 527. 



4 Mackie, On the Laws that Govern the Rounding of Particles of 

 Sand, p. 311. 



5 Ibid., p. 300. 



6 Mackie, The Felspars Present in Sedimentary Rocks as Indicators 

 of the Conditions of Contemporaneous Climate, p. 459. 



7 Mackie, On the Laws that Govern the Rounding of Particles of 

 Sand, p. 307. 



8 Mackie, The Sands and Sandstones of Eastern Moray, p. 148. 



9 Ibid., p. 150. 



