A Compostelan Cross is also referred to as a Scallop Shell Cross.
What's a 'Compostelan'?
The Scallop Shell Cross is formed by several ... yes, you've guessed ... scallop shells.
Pecten shells are such useful items. They start life as homes to sea molluscs, and when their host dies, they lie provocatively on the sand waiting for some beach-comber to come along and say "Wow!" Then they are taken home to be used as ashtrays or soap dishes for a couple of years before they are thrown out with the household rubbish. Some fare better and become picture frames, lamps, jewelry, or musical instruments. And some are used to make a cross.
We shouldn't write-off such handicrafts as tacky ornaments - over 100 years ago, boxes covered in oriental shells were such a popular import item for a Victorian shipping company, that they named their company "Shell". Since then, the company has grown to be one of the most successful energy and petrochemical companies in the world.
Another reason the company decided on the pecten shell for its logo was because the family of an early financier, Mr Graham, had a coat of arms that included such an emblem. Mr Graham's ancestors had pilgrimaged to Santiago de Compostela, the tomb of St. James, and since the Middle Ages countless European pilgrims have visited this tomb. (See also St. James's Cross)
Pilgrims would pick up a scallop shell from Galicia as a souvenir of their journey and evidence that they had visited the shrine of St. James. Pilgrimages to other sites had similar customs of bringing back souvenirs which were more than just mementos; they would wear them as a cap badge as a 'passport' to show bandits and local authorities they were passing in peace and meant no harm. The shell could also be used as a scoop or spoon for the pilgrim to feed himself modestly at an abbey where he might stop for sustenance. The shell would be a sign to potential hosts that the pilgrim did not beg for much food.
"A bolle and a bagge
He bar by his syde
And hundred ampulles
On his hat seten
Signes of Synay,
And Shelles of Galice,
And many a conche
On his cloke,
And keys of Rome,
And the Vernycle before
For men sholde knowe
And se bi hise signes
Whom he sought hadde"
(Piers Plowman)
The shell has also become a baptism symbol. It has been found in artwork discovered in ancient Christian catacombs and also in Renaissance art. Often John is depicted baptising Jesus by pouring water from a scallop shell1.
A shell symbol features in many family crests (for example, that of the late princess Diana), and prominently in the logo of the Methodist Church in Kenya (MCK) and the Methodist Church of Southern Africa (MCSA).
The Methodist Church Nigeria (MCN) logo shows a small shell beneath the Agnus Dei over an outline map of the country.
In addition to being a symbol for baptism, another reason for the scallop shell motif on Methodist logos may be from its appearance beneath a 1778 engraving of John Wesley, thus becoming a de facto family coat of arms.
A gold shell symbol has been incorporated into the papal coat of arms of Benedict XVI. There are three reasons for this:
Finally, here's a little humorous story of another guy walking on the beach, picking up sea shells.