Ages 9–11🔬 Science9 verified questions on this shelf
Rock Layers & Relative Dating
Understand that rock layers (strata) form in sequence with the oldest at the bottom and the youngest at the top, and that fossils found in deeper layers are older — this is the principle of relative dating
Try three questions
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Question 1 of 3
A geologist studies a canyon wall where four sedimentary layers are visible from bottom to top and are named Layer W, Layer X, Layer Y, and Layer Z. A fossil of a giant fern is found in Layer X, a fossil of a small shark is found in Layer Y, and a fossil of a dinosaur bone is found in Layer Z. Years ago a landslide removed the original bottommost layer (Layer V) that used to be below Layer W. Which statement correctly describes the relative ages of the three fossils that are still present?
Question 2 of 3
A geologist is examining a quarry where four sedimentary layers are visible. From bottom to top they are called Layer 1, Layer 2, Layer 3, and Layer 4. The top part of Layer 1 was worn away before the quarry was studied, so only the upper portion of Layer 1 can be seen. A fossil of an ancient fern is found in Layer 2, and a fossil of a marine snail is found in Layer 3. Which fossil is older, and why?
Question 3 of 3
Scientists examine a quarry that shows three sedimentary layers. The lowest layer (Layer 1) holds a fossil of a tiny mammal, the middle layer (Layer 2) holds a fossil of a duck‑billed dinosaur, and the top layer (Layer 3) holds a fossil of a pterosaur. Which statement correctly describes how the scientists can decide which fossil is the oldest using relative dating?
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