Web this packet will help students to have a better understanding of the basic principles used to determine the age of rocks and fossils. _____ 6.2 geologic time 6.2.2 relative dating the law of superposition in any undisturbed sequence of strata, the oldest layer is at the bottom of the sequence, and the youngest layer is at the top of the sequence. Students read about fossils, relative dating, the law of superposition, and the three traits of an index fossil. Columns i and ii contain rock layers a, b, c and d, e, f. Students read about fossils, relative dating, the law of superposition, and the three traits of an index fossil.