erosion lines of stratified sedimentary rocks in steep mountainside

erosion lines limestone karst karstic landform stratified rock rocky strata stratification stratigraphy glacial lithology geology layers sediments layering steep vertical rough relief topography slope facies green grass landscape detail nature outdoors mountain cantabria valles pasiegos miera valley valle del spain land natural environment ecology spring horizontal color cantabrian mountains water river wearing away sedimentary rocks mountainside