Gay Marriage in California (or not)

I am puzzled by the California Supreme Court's decision last Tuesday, validating Proposition 8.

The irony is that the prior decision by Chief Justice George (granting gay couples the right to marriage) stated that the ability of all people to marriage is a fundamental right. As such, under the California Constitution, any change to that status must be made by an Amendment to the Constitution, with a specific set requirements--most definitively passage of the bill by super-majorities of both State legislative houses.

Prop. 8, which took away what Chief Justice Ronald George termed a fundamental right, by a bare majority of the voters, was never considered by either house. And I would bet that with Democratic majorities in both houses, it would never pass.

I'm remain, as I started, puzzled as to how the court got around this requirement.