The pebbles on the shore were pitch.

I think your common sense will tell you that these pebbles are not mere concretions; that is, formed out of the substance of the clay after it was deposited.

"A score of times ere now I had seen them fall and receive no damagethis time, as Lucy Snowe's hapless luck would have it, they so fell that each clear pebble became a shivered and shapeless star.

The round pebbles in it being, I believe, pieces of Old Red sandstone, may have come from the great Old Red sandstone region of South East Wales and Herefordshire.

It is too late now; but the dull colorless pebble might have been the bright glancing gem.

The little pebble was five feet from the earth."