When I dug my hole down there, I happened to land in the corner of this cave/platform. Just a few blocks off and I would have hit more stone without going anywhere, or falling much further. I was promptly met by an Enderman, but he was cool about it and left me alone.
So here's a cave I was met with upon landing. I lit it up with a few torches before running into a zombie mob, so I turned back.
Turning directly around, I was met with a sheer cliff!
The water below was too shallow to cushion a jump, but walking along a narrow walkway along the cliff I found some water that ran two ways: one formed a waterfall leading below, and the other end ran into a cave. Down the cave I found a Creeper (not pictured) and a Spider, so I placed torches as close as I could and hightailed it out of there.
Going down the waterfall slowly I landed on a ledge, which the Enderman teleported to!
He wasn't going anywhere so I couldn't look along the ledge any further, so I continued down the waterfall to the floor of the cavern, which housed several different ores.
Continuing in either direction led to a dead end, once you got past the water and lava.