When this site was ploughed in the 1930s a funerary urn was discovered. But this was more than just another round barrow. Until it was removed in 1912, a seven foot standing stone topped the mound (7'1" x 1'6" x 7", according to the Coflein record).
I'm assuming it is the same one spoken about by Janet Bord in her 'Fairy Sites' book (2004). Her informant Paul Parry apparently knew the site as 'Carreg y Dol' and that a goblin (an ellyll) guarded the site and the treasure that it contained.