The metamorphic rocks of western Crete form a series some 9000 to 10,000 ft.
The central plateau consists almost entirely of metamorphic rocks with extensive tracts of granite in Unyamwezi.
In many deposits of iron ores found in connexion with igneous or metamorphic rocks small quantities of phosphate occur.
Consisting of red sandstones, mudstones and conglomerates, they are inclined at high angles usually away from the granite massif and the encircling metamorphic rocks.
They occur (a) in crystalline igneous and metamorphic rocks as an original constituent, (b) in veins associated with igneous rocks, and (c) in sedimentary rocks either as organic fragments or in secondary concretionary forms.