heart cockle
... that Shell Beach in Western Australia is entirely composed of empty shells of the heart cockle?
... that <a href="./Shell_Beach_(Western_Australia)" id="mwD-Q" rel="mw:WikiLink" title="Shell Beach (Western Australia)">Shell Beach</a> in Western Australia is entirely composed of empty shells of the <b id="mwD-U"><a href="./Fragum_erugatum" id="mwD-Y" rel="mw:WikiLink" title="Fragum erugatum">heart cockle</a></b>?