Hmm...have you looked at Smalltalk-72?

Now Alan makes it clear that the inspiration for Smalltalk OO came from Simula (and a bit from the Burroughs 220 and 5000, from Sketchpad etc.), but to say that Smalltalk is just that is a stretch at best.

The more direct line goes from Simula (Algol with classes) to C++ (C with classes).