We have studied the petrology of three type 4 carbonaceous chondrites, Coolidge, Karoonda, and Pecora Escarpment 82500, which was previously classified as an LL6 chondrite, and compared them to published descriptions of the other known metamorphosed C chondrites, Yamato 6903 and Mulga (west). All except Coolidge have abundant matrix, typically 80 vol %, composed largely of homogeneous olivine, Fa 29--33, and surprisingly heterogeneous plagioclase, mostly An 20--75. Their opaque mineralogy indicates high oxygen fugacities during metamorphism: metallic Fe, Ni and troilite are rare, and magnetite and pentlandite are abundant with accessory pyrrhotite, chalcopyrite, and pyrite. Possibly because of a lower matrix abundance, Coolidge has more reduced minerals: metallic Fe, Ni and olivine with Fa 14. The properties of all C4--6 chondrites appear to be consistent with an origin by metamorphism of C3-like precursors by processes analogous to those operating in ordinary chondrite parent bodies or planetesimals. However, type 4--6 material was not well mixed with type 3 material in the CV3 parent body, as it was in the ordinary chondrite parent bodies. Conceivably, C4--6 chondrites come from one or more separate parent bodies.