One of the oldest ritual tools in Witchcraft is the shell or bowl. Originally large shells were used to contain seawater for blessings and ritulas. The moon as long been associated with the tides of the ocean, so seawater is considered to contain the essence of the Moon's power, and shells are an old traidtional symbol for the Goddess.

In Italian Witchraft, it was common to use either a large round stone, or the log, or stump of a fallen tree as an altar, uponm this the shell bowl would be placed with the open end faced up. I can imagine that abalone shells would have been those most likely used, becasue thier shape and size sounds about right for use as a bowl.

Upon the altar a cirlce of small white shells were placed around the bowl, forming a cresent shape just below the bowl. Once the ritual was over the shells were removed one at a time from left to right.

Over time the use of shells as bowls began to change, and more commonly the use of gourds, wooden, or cermaic bowls grew in popularity.