Wow, that has got to be the largest mass of flat grass land I have ever seen. I always get hill bloody everywhere which makes building large things a pain in the ass.
Assuming by some of the half-buried trees, it's possible that he may have dug the dirt away.
It made finding a wolf quite hard. Had to travel for miles to find a forest and then got lost, camped out, got redstone and finally found my way back to my house. D:
You can still dig grass away.
Oh and Acid, what's that seed and the coords?