Henry David Thoreau, Walden or life in the woods, Boston, Houghton Mifflin and Company, 1854.

There are many furrows in the sand where some creature has travelled about and doubled on its tracks; and, for wrecks, it is strewn with the cases of cadis worms made of minute grains of white quartz . Perhaps these have creased it, for you find some of their cases in the furrows, though they are deep and broad for them to make.

Chapitre XIII House-Warming