Giant Turtle? Or Rotting Whale Blubber?

Did the decaying remains of a previously uncatalogued Giant Turtle just turn up?
Cryptomundo has posted a series of photos of a massive carcass that washed up on a Pacific Ocean beach. No official word on what the hell it is, but the theories rage.

Is it a rotting whale carcass, or a giant turtle on its back?
There was a monster-sized turtle species that roamed the oceans about 70 million years ago called the GiantArchelon ischyros. One set of fossilised remains showed the creatured measured 16 feet long.
The theories on what those photos show are flowing here, but most presume it is a whale carcass of some kind.
Damn, and we thought it might be proof that Gamera's body had been found after its final, heroic battle against Godzilla.