Attached crash report.
Looks like cobble to me in the latest snapshot.
Horses do not usually jump by themselves. Were you riding it? Otherwise, their AI might not look for holes.
Happened to me when trying to tp relative to my location, which was at bedrock at the time.
Cannot reproduce. All inventory features seem to be working for me.
Confirmed happening in 13w24b, camera wobbles back and forth against the movement of the cart.
Was able to reproduce.
Duplicate of already reported issue.
Duplicate of already reported issue.
Confirmed on Windows 7 with Java 7.
Still occurs in MC 1.6.2