From reading a number of river history books, it seems the grand canyon in the earlier days of being boated, was often called "The canyon", contemporary river runners are more likely to call it " The Grand". Terminology has changed over the years for various aspects of river running, and i'm guessing that is where tton is coming from.
My generation of river guides reffered to the hole in low water sunshine as the crux hole, since my last time hanging out at corner pocket, it seams kids these days are calling it "el diente" instead.
Can't fight against the youth though, as they will still be boating after i'm reduced to worm food, or running rapids bert loper stile if i'm lucky!
" I wish I were a headlight, on a North bound train..."