and if you believe God exists, you got that from the Bible, so you must also believe the rest of the Bible, so you must believe all literal statements made in the Bible.
God wrote the rocks, Man wrote the Bible.
What the rocks tell us is true. What the Bible tells us may or may not be true. Parts of the Bible are true, parts are not. I have yet to see a "literalist" who actually believes everything in the Bible without "interpretation", AKA "not literal".