These rocks are frequently metamorphosed greenschist, amphibolite, and granulite facies. It is called French Creek Granite although it has been metamorphosed into gneiss. The constituent rocks are metamorphosed sediments. The oldest rocks are Proterozoic, metamorphosed sediments. The majority of the rocks are weakly metamorphosed coarse greywacke. The first are so-called greenstone belts, consisting of low-grade metamorphosed sedimentary rocks. Conditions producing widespread regionally metamorphosed rocks occur during an orogenic event. They have been metamorphosed to greenschist or low grade amphibolite. The rocks have metamorphosed and are deeply eroded and faulted. These were metamorphosed and deformed in the Cretaceous. The oldest rocks are Permian sediments of the Swanson Formation, which is slightly metamorphosed. Grossular is found in skarns, contact metamorphosed limestones with vesuvianite, diopside, wollastonite and wernerite. It also occurs in carbonatites and metamorphosed magnesium-rich limestone. They are metamorphosed basement rocks from prior to the Miocene. Monticellite is found in contact metamorphosed dolomites.