Sing that again?

After listening to a CD of kid's worship songs which included a song with the lyrics, "Trust in the Lord forever, for The Lord, the Lord is the rock eternal, the rock eternal" I caught Megan singing it. Only her version went, "Trust in the Lord forever, for The Lord, the Lord is the rocky turtle, the rocky turtle." When I asked her about it, she said she knew how it really went, but there was a hesitancy in her voice that made me doubt her.