Please help ID Mark on marked sterling enamel locket?

[seelly]

can anyone id this mark on this necklace? was thinking it may be the mark of Meyle & Mayer who were German jewelers in the early 1900's but was told that it was not. Their mark is a dragonfly.
The mark is difficult to make out even with a 30x loupe because it's worn.
Any other ideas on the marking?
The necklace is enamel on sterling with marcasite, garnets and diamonds. At least that's what my gem tester is reading. Will take it to a jeweler for verification when I find new one to go to.
THanks!