Siton Undae
... that the Martian dunes of Siton Undae are mostly composed of volcanic glass?
... that the <a href="./Mars" id="mwBZE" rel="mw:WikiLink" title="Mars">Martian</a> dunes of <b id="mwBZI"><a href="./Siton_Undae" id="mwBZM" rel="mw:WikiLink" title="Siton Undae">Siton Undae</a></b> are mostly composed of <a href="./Volcanic_glass" id="mwBZQ" rel="mw:WikiLink" title="Volcanic glass">volcanic glass</a>?