Chunk Error Confusion (My Bad)

When I checked out part of my base at y=20-ish there was some granite there that I know wasn't there before. I have no idea where it came from and I got creeped out. Seriously, this chunk was first generated in 1.7.3 or 1.7.4 and shouldn't have granite. I looked all over and there was only 2 veins of granite in the whole chunk. There was not even diorite or andesite. It's connected to my base (1.7.3) and only like 6 chunks away. Plus, the light level was all fudgey.