Continuous cleavage goes upto high metamorphic grade-amphibolite facies. A slaty cleavage is very closely spaced cleavage with planes
on < 0.1 to perhaps 1 mm scale at the upper limit. A smooth highly penetrative foliation consisting of parallel orientations of clays or micas. Penetrative to microscopic scale. The kind of rock that is normally used for roofing or kitchen table tops. Slaty Cleavage is a
type of foliation expressed by the tendancy of a rock to split along parallel planes. This should not be confused with bedding planes, which are sedimentary structures not related to natural tectonic forces.
Slaty cleavage results from the parellel orientation of microscopic platy minerals. Phylitic Cleavage and Schistosity are progressively more coarsely crystalline penetrative foliation.
Gneissic Layering: Strong compositional banding defines foliation. High grade metaorphic rock have spaced or disjunctive broadly spaced cleavage.