The Schierholz porcelain factory was founded in Plaue, Thuringia in 1817 and this mark was introduced to commemorate the 150th anniversary of the factory in 1967.
This tureen and cover is typical of the decorative wares produced by this factory often influenced by pieces made at the Meissen factory. C19th Plaue pieces are considered very collectable.
It has one small chip in a blue petal on the lid, otherwise, it is in perfect condition. I’ve had it appraised and can provide a certificate. The apprasial came in between $100 -$150.