This Ordovician rock is composed of laminated mudstone and siltstone with greywacke sandstone. The basalts are interbedded with slate and greywacke, faulted, and intruded by granitic rocks. This area is dominated by steep sandstone, greywacke and mudstone hills and winding valleys. Siltstone, greywacke, iron formation, ferromanganiferous shale and chert represent minor rocks. Soils vary between slate, basalt and greywacke clay of volcanic origin. The Crimson Creek Formation consists of greywacke with tholeiitic basalt. It mainly has quartzite, marble, pelite, greywacke and extinct volcanos exposed in the Aravalli-Delhi Orogen. Also, another sequence of interbedding calcareous greywacke and carbonaceous shale is found. The majority of the rocks are weakly metamorphosed coarse greywacke. These sediments compacted into horizontal layers of shale and greywacke. Bluestone from Pennsylvania and New York is sandstone defined as feldspathic greywacke. Only fragments remain of the sarcophagus, which was probably made of greywacke or basalt. In the North Island they were commonly made from greywacke or basalt. The underlying rock is Malmesbury shale with a zone of greywacke and quartzitic limestone. Bruce is dominated by the greywacke of the Ordovician Pittman Formation.