OP,
I STRONGLY suggest your son apply to USC, which, as mentioned above, has a superb geology dept, accepts MANY transfer students, offers great FA to transfer students, and even has scholarships available for them.
DS was a Geology major / Physics minor at USC and found the dept offered more geology classes than he could possibly take. He was able to take some of the graduate geology classes as well.
http://dornsife.usc.edu/earth/undergraduate-courses/
I do suggest that your DS take some physics classes, as they are prerequisites for some of the more advanced geology classes.