580 PERMANENCE OF DUNES. 
been able to learn from my own observation, or that of others, 
is the same. Thirty years ago, when that region was scarcely 
inhabited, they were generally covered with a thick growth of 
trees, chiefly pines, and underwood, and there was little ap- 
pearance of undermining and wash on the lake side, or of shift- 
ing of the sands, except where the trees had been cut or turned 
up by the roots.* 
Nature, as she builds up dunes for the protection of the sea- 
shore, provides, with similar conservatism, for the preservation 
of the dunes themselves; so that, without the interference of 
man, these hillocks would be, not perhaps absolutely perpetual, 
but very lasting in duration, and very slowly altered in form or 
position. When once covered with the trees, shrubs, and her- 
baceous growths adapted to such localities, dunes undergo no 
apparent change, except the slow occasional undermining of 
the outer tier, and accidental destruction by the exposure of the 
interior, from the burrowing of animals, or the upturning of 
trees with their roots, and all these causes of displacement are 
very much less destructive when a vegetable covering exists in 
the immediate neighborhood of the breach. 
Protection of Dunes. 
Before the occupation of the coasts by man, dunes, at all 
points where they have been observed, seem to have been pro- 
tected in their rear by forests, which served to break the force 
* The sands of Cape Cod were partially, if not completely, covered with 
vegetation by nature. Dr. Dwight, describing the dunes as they were in 1800, 
says: ‘‘Some of them are covered with beach grass; some fringed with 
whortleberry bushes; and some tufted with a small and singular growth of 
oaks. . . . The parts of this barrier which are covered with whortleberry 
bushes and with oaks, have been either not at all or very little blown. The 
oaks, particularly, appear to be the continuation of the forests originally 
formed on thisspot. . . . They wore all the marks of extreme age ; were, 
in some instances, already decayed, and in others decaying ; were hoary with 
moss, and were deformed by branches, broken and wasted, not by violence, 
but by time.” —7Travels, iii., p. 91. 
