Windows 7 sp1 64bit
java version "1.8.0_20"
Java(TM) SE Runtime Environment (build 1.8.0_20-b26)
Java HotSpot(TM) 64-Bit Server VM (build 25.20-b23, mixed mode)
Got the vertical cave in my village
One day, I changed the Java version form 1.8.0 64bit to 1.8.0_b20 64bit,
and I got the vertical cave in my village.
And I changed the Minecraft version form 1.7.10 to 1.8-pre2, the cave has exists.
In Minecraft version 1.7.10, I can jump to the cave.
In Minecraft version 1.8-pre2, I lost my lift used Shift+W key near the cave.
Attachment is form Minecraft version 1.8-pre2.