Up from the far beach

At the far right of the beach the ground steps up too high to climb, so the far beach seems to be a dead end.
Nudge 1Where to look
Dizzy needs something to stand on.
Nudge 2A stronger push
Something empty lies in the wreck of the old galleon, under the bay.
What you needOther problems to solve first
Solve these first (each opens its own page, no answers on the way):
Show the solutionThe whole answer, with a video
Bring the empty treasure chest up from the wreck and drop it at the foot of the step on the beach's far right. It stays there as a step: Dizzy climbs onto it, and on into the grasslands' west part.