1904 May 92 Sigma Phi Epsilon has long since passed the point where it is a question whether it will live or die. It stands to-day on a rock-solid foundation.
1972 (Sunday Times Insight Team) xvi. 273 They had seen their support in the area—once rock-solid—steadily and severely eroded.
1996 Mar.–Apr. 20/1 His credentials as a practitioner are apparently rock-solid.