PLEASE HELP In this laboratory experiment, you will write a narrative history of a rock section found in the Grand Canyon. You will describe and explain the events starting with the Vishnu Schist forming and ending with the unconformity above the Redwall Limestone in the Mississippian. Your description should include environmental changes. 1.Interpret the bottom half of the cross section below. Start with the Vishnu Schist and end with the Redwall Limestone.