[Seeing Sorey perk up cheers him even more than just getting some breathing room here, he must admit. And now that he's brought up their favorite subject, he can't help but be drawn into the debate...]

I doubt we'll find much if any evidence in this area -- unless it's buried and we just haven't tested the seafloor enough yet. It's all supposition right now without any artifacts or evidence, but either's possible. Though it may not all come down to equipment, if that's the case, since we're talking about potentially very different lifeforms from Glenwood's; they may have been amphibious, or they could have lived at much greater depths than this. Or they could have other adaptations we can't even imagine. In any case, I doubt any ruins left behind will be anything like we're used to.

[...which means the possibilities are endless.]