I just thought I should give you some info about pottery marks for the various incarnations of this pottery manufacurer. One great site for finding staffordshire pottery marks is www.thepotteries.org and the Bible of pottery marks is Goddens which is a very expensive tome. But here, for your delectation, is the minimum you'll need to know about Powell & Bishop, Powell Bishop & Stonier, and Bishop & Stonier. The key marks that you'll see on their pottery: i.) the wand of Caduceus ( a rod entwined by serpents flanked by a pair of wings - based on the Hermetic symbol and similar to the medical symbol) and ii.) a chinaman under a parasol for the Oriental Ivory range. The works of this factory are usually very well marked (except for some small pieces like saucers) so you can usually spot one of their pieces quite easily. Also, to my knowledge, there has been no fad for faking/forging their works as there aren't many pieces that command massive prices (except for the White Star Line wares), so you can be pretty confident that when it's marked, it's the genuine article. The factory tended to be fairly consistant in their marking of pattern names and numbers. I haven't, as yet, found out if individual painters and paintresses had marks - if anyone out there knows, please do tell me.