5*4 



PRESIDENTIAL ADDRESS. 



[Proc. B.N.F C. 



SAND-HILLS : THEIR FORMATION, FAUNA AND FLORA. 



On the evening of Tuesday, 21st November, the President, 

 Mr. R. J. Welch, M.R.I.A., read his address on "Sandhills, their 

 Formation, Fauna and Flora," before a large and representative 

 audience. The President said, in the course of his address, coast- 

 dunes are one of the small compensations for the waste of the land 

 by the sea in other places, and they are formed by the wind, one 

 of the main causes of denudation. Once formed they become the 

 best protection against marine erosion. Dunes form rapidly where 

 the sea accumulates sand above the low-water mark, so that it 

 becomes dry between the tides. This may be seen any windy day 

 ■on strands if the tide be low, especially if the wind is blowing 

 landwards. It may be asked from whence the enormous amount 

 of material in our big sand-hills is derived. The material, at least 

 •on our east coasts, is almost entirely fine quartz grains. It is formed 

 by marine erosion, and the disintegrating action of frost, while 

 rivers are constantly bringing down debris from the hills, and from 

 their own beds. The sand-hills so common at the mouths of 

 many rivers are largely formed by the material brought down by 

 these rivers, and the material forming them may have done duty 

 many times before in past geological periods, for the sandstones 

 ■of to-day are only the consolidated lake, sea, or aeolian sands of 

 ( Cetaceous, Triassic, Carboniferous, or more ancient times. The 

 Glacial Period, too, left behind enormous quantities of loose 

 friable material containing much fine gravel and sand. Though 

 the great majority of dunes in temperate regions are formed of 

 siliceous material, yet we have in the west of Ireland and in 

 Devon and Cornwall areas of more or less calcareous dunes 



