Cala d’Or (Mallorca); mariene schelpen zoeken op het droge

In July 1997 the author stayed two weeks at Cala d’Or on Mallorca, Spain. Neither on the beaches (beachcombing), nor in the sea (snorkeling) he found many different species. But on rocks some 4 meters above sealevel he found hundreds of shells, mostly of very fine quality. In total he found 57 different species. On other comparable rocks nearby however he didn't find shells at all. He wonders whether other (amateur) malacologists have similar experiences and/or can offer an explanation for this peculiar find-spot.