Tabular blocks of layered ash in a matrix of cross-bedded ash deposited by ancestral Missouri River

Typical exposure of tabular blocks of layered ash in a matrix of cross-bedded ash. The tabular blocks were deposited, rapidly hardened, and ripped up and transported downstream along the ancestral Missouri River system with another pulse of ash and water, forming the cross-bedded matrix. Black-colored Leatherman multitool for scale.  Photo by Rob Thomas, August 2021.