The Lost World as a title already does half the work before anyone even sees the painting. You're marking this as a body of work, not just one piece, and that changes how people read it. I did a gouache series a few years back from a trip through Portugal, sketched the same doorway six different times across three days, different light each time. Didn't think to call it anything until someone asked if they were studies or a set, and naming it suddenly made it feel like the thing I'd been building toward instead of just six tries at the same spot. Sounds like you've got that clarity already.

I've been thinking about that permanence question a lot lately. Oil on canvas lets you come back, layer over, adjust until it's where you want it, but the thing you're painting toward still has to live somewhere clear in your head or the whole piece wanders. Stone only goes one direction, which sounds limiting until you realize it just moves that same problem earlier. You still have to know what world you're after before you start taking away. A lost world collection sounds like exactly that kind of sustained vision, the kind that holds through however many pieces it takes to say the whole thing.