Video (starting at 0 min. 22 sec.): http://www.youtube.com/watch?v=UnAXKuX1Q-c#t=0m22s
Transcript for that section:
There is many a theory about the traveling stones including a few that involve aliens. Ice was the most popular idea for quite some time, and the guess was that the stones got trapped in it and the whole sheet moved, rock and all.
What really happens is the rock does indeed get frozen in the ice, but eventually the ice on the outer edges melt. The lightened stone and ice combo are then pushed effortlessly along by the wind, leaving a furrow behind them.
First of all, I don't quite understand how rock and all is connected to the rest of the sentence and what he's trying to say. The sheet and the rock and everything else is moved? Then where's the article?
Second. Is the subject the lightened stone and ice combo plural? If so, then it's not completely clear what he means by ice combo if we should think of it as a separate thing. But to me, it sounds like lightened stone and ice must be an adjective that's describing the combo. If so, then we must use is instead of are. It's kind of confusing.
Also, I believe there's a mistake in the script that he's reading. It should be melts.