Deformed conglomerates | AMNH https://www.amnh.org/exhibitions/permanent/planet-earth/why-are-there-ocean-basins-continents-and-mountains/mountain-building/how-rocks-deform/deformed-rocks/deformed-conglomerates
These rocks were originally deposited in a stream as layers of rounded pebbles.
Deciphering the Grand Canyon Uplift and Erosion