Precambrian formations include highly metamorphosed crystalline rocks and are distinguished as Pelagonian Horst Anticlinorium (also known as the Pelagon,[citation needed] or the Pelagonian Massif[4]) together with some blocks in the Vardar Zone.[4] They are widely distributed in the Serbian-Macedonian Massif.[4] The lower part of the segment includes gneiss, biotite, muscovite, magmatized and augen gneiss, metagabbro, eclogite, amphibolite, amphibolite shale and micaceous marble. In the upper segment are different types of mica schist, granite, kyanite and staurolite. The upper Precambrian of the Pelagon Horst Anticlinorium include mixed series of gneiss, mica schist, barite, cipolem, marble and metarhyolite together with calcite and dolomite up to three kilometers thick.