De Silva, M.C. <br/><br/>
පෘතුවිය 
 Pruthuviya 

 -  Education department  1975 
 - 32p., ill.,  25 cm 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Earth <br/>Ocean <br/>Sea <br/>Mineral <br/>Mineralogy
<br/><br/><label>Universal Decimal Class. No.: </label>551.1  / DES