layer puzzle

I think that the order is  4,5,2, b, a ,6,1 & 3 because 4 is lowest then 5 then. Then 2 because the intrutions are younger than everything they cut through. Next is B because it cuts through 5 and 4 then A because it levels it out. Next is 6 and 1, after that is 3 because it cuts through all of them.