Almost vertically TO ½ to 1, at a great height,
a slow regular crumbling of the surface or falling down of small fragments, which seldom produce serious movement in such material, being the only deleterious effect of weather influences.
As the chalk becomes broken and less evenly bedded,
about 1 to 1.
Loose, friable chalk in surface beds will often not permanently stand at a less slope than from
1 to 1 TO 1½ to 1,
according to the depth and degree of exposure. The most usual slopes being
½ to 1 TO 1 to 1.
Impure wet chalk and marly chalk will require a slope not less than
1½ to 1.