The beds that make up this cliff vary in thickness, color, cementation and resistance to erosion. The variable properties seen here impact the topography as we gradually work our way through each layer further upstream. Starting at the stream bed, the Berea Sandstone overlies the Bedford Formation that we first encountered about half way up the stream. The contact is somewhere in the weak shales that separate the two units. It is the lowest layer seen on the cliff, and the one that is now undercutting the big waterfall. Next is a resistant series of sandstone beds that form the caprock of the big waterfall around the bend. It in turn is overlain by a friable (easily crumbled), yellowish, cross-bedded layer of weak sandstone that erodes into recessed alcoves, as seen on this cliff and on the stream banks upstream. Barely visible as a dark line is the “thin limonitic zone,” a one-foot-thick bed rich with iron oxide minerals. Next is the massive layer where we see a cross-section through an ancient delta as it gradually fills the Ohio Bay some 350 million years ago. The final rock bed consists of thin, interbedded shales and siltstones that form the scenic, step-like cascades leading up to the exit trail.
|Return to Stop 10|