Merrill, Robert H., 1881-1955, “Ladder & metric grid on sand, shade Macatawa,” Digital Collections, accessed April 2, 2025, https://digitalcollections.library.gvsu.edu/document/50421.
Black and white photograph of two metric measuring grid squares next to a measuring stick on sand. Part of a camera ladder rig system developed by Merrill for taking overhead photographs of archaeological excavations.