476 
SAND CONCRETIONS IN DUNES. 
formed ? To wliat was it once fixed ? What power broke it 
loose ? How was it beaten smaller and ever smaller by the 
waves ? They tossed it, for aeons, to and fro upon the beach, 
rolled it up and down, forced it to make thousands and thou¬ 
sands of daily voyages for millions and millions of days. Then 
the wind bore it away, and used it in building up a dune; 
there it lay for centuries, packed in with its fellows, protecting 
the marshes and cherished by the inhabitants, till, seized again 
by the pursuing sea, it fell once more into the water, there to 
begin the endless dance anew—and again to be swept away by 
the wind—and again to find rest in the dunes, a protection 
and a blessing to the coast. There is something mysterious 
about such a grain of sand, and at last I went so far as to fancy 
a little immortal spark linked with each one, presiding over 
its destiny, and sharing its vicissitudes. Could we arm our 
eyes with a microscope, and then dive, like a sparling, into 
one of these dunes, the pile, which is in fact only a heap of 
countless little crystal blocks, would strike us as the most mar¬ 
vellous building upon earth. The sunbeams would pass, with 
illuminating power, through all these little crystalline bodies. 
We should see how every sand grain is formed, by what mul¬ 
tifarious little facets it is bounded, we should even discover 
that it is itself composed of many distinct particles.” * 
Sand concretions form within the dunes and especially in 
the depressions between them. These are sometimes so exten¬ 
sive and impervious as to retain a sufficient supply of water to 
feed perennial springs, and to form small permanent ponds, 
and they are a great impediment to the penetration of roots, 
and consequently to the growth of trees planted, or germinat¬ 
ing from self-sown seeds, upon the dunes, f 
* J. G. Kohl, Die Insetn und Marschen dev Herzog thinner Schleswig und 
Holstein , ii, p. 200. 
t Staring, De Bodem van Nederland , i, p. 317. See also, Bergsoe, 
JRevenUov's Virksomhed , ii, p. 11. 
“In the sand-hill ponds mentioned in the text, there is a vigorous 
growth of bog plants accompanied with the formation of peat, which goes 
on regularly as long as the dune sand does not drift. But if the surface of 
the dunes is broken, the sand blows into the ponds, covers the peat, and 
