As seen in 'REPORT_COMPARISON.png', the terrain generated in Minecraft Java Edition snapshot 18w06a differs from the same terrain generated with Minecraft Java Edition stable 1.12.2. One can clearly see that those mountain shaped formation is more far away and is shaped entirely different in 1.12.2.

Steps to reproduce:

• generate a world with the seed noted in both 18w06a and 1.12.2
• teleport to 149 // 115 // 571
• look to the south
• the formation should be different

Tinier differences were seen at 100 // 200 // 100, turning downwards and looking to the south.