BT Yev 94a(34) :הוה ליה לר׳ אלעזר בן מתיה למידרש בהאי קרא מרגניתא ודרש ביה חספא‏ : could have interpreted a 'pearl' [i.e. a valuable interpretation] regarding this verse, but (instead) he interpreted regarding it an 'oyster shell' [i.e. a worthless one]
See the entire entry for drš vb. to tread; to expound