I'm happy the way the strata worked out here. A fractal terrain includes twist and shear; 'dandelO's' 10M cracks file; and, FrankB's suggested method of attaining strata irregularity. The darker upper surface layer blends nicely with the base color; and, includes an array of four sizes of fake stones which are the same color as the upper surface layer.
Also included are:
• dandelO's Cumulus Fractus clouds.
• Walli's Big Dense Pine.
• Walli's Pine.
• lightning's bushes.
The image was adjusted for brightness /contrast in PS.