Cleveland shale is usually a black layer of sedimentary rock, lying below Euclid bluestone and Chagrin shale. Part of the huge Marcus shale formation, the rock is rich in oil. Cleveland Shale can yield an average of 14 US gallons of oil per 1 short ton of rock, and is 360 to 358.9 million years old, dating to the latest Devonian era.
It’s only when it is exposed that it turns red. In fact there is no iron at all, but chlorite, illite, pyrite and quartz. Normally it is black. Shot straight up and against the overhanging sedimentary cliff face.