Contents of a Normal Sussex County Boy's Pockets in 1855

From the Delaware State Reporter newspaper, issue 2 March 1855, which has said a boy is very miscellaneous in his habits and when they emptied Master Smith's pockets the other day, they found the contents to consist of these articles; sixteen marbles, one spin top, an oyster shell, two chips of a brick, one doughnut, part of a curry comb, a paint brush, three wax ends, a handful of corks, a chisel, two knives, both broken, a skate strap, three buckles and a dog eared spelling primer.
Everything seems normal except the oyster shell and the bet is that he carried it to drink water out of a deep well or fresh spring. Whats your best bet?