Land changes over time

This task is about rock layers and fossils.

We can learn a lot about changes in the Earth's surface by looking at a cutting through the surface layers.

Here is a diagram of a cutting through the side of a hill.

Question

a) Which layer in the diagram best fits each description below?

i) Formed on low-lying land that was covered with dense forests

- A - Fossilised shells in sandstone
- B - Limestone
- C - Fossilised reptile bones
- D - Coal

Which layer in the diagram best fits each description below?

ii) Formed from finely crushed shells and bones of sea creatures

- A - Fossilised shells in sandstone
- B - Limestone
- C - Fossilised reptile bones
- D - Coal

b) Which is the youngest layer?

- A - Fossilised shells in sandstone
- B - Limestone
- C - Fossilised reptile bones
- D - Coal

d) Which two layers were formed under the sea? (Choose two)

- A - Fossilised shells in sandstone
- B - Limestone
- C - Fossilised reptile bones
- D - Coal

			Y7 (07/1997)	Y8 (07/1997)
a)	i) ii)	D - Coal B - Limestone	moderate very difficult	easy difficult
b)		A - Fossilised shells in sandstone	easy	easy
c)		Because it is harder/more compressed or A is softer/less compact	very difficult	difficult
d)		A - Fossilised shells in sandstone and B - Limestone	difficult	difficult
e)		Dense forest on low lying land Dinosaurs roaming the land Change in sea level resulting in deep sea Sea becoming shallow	very difficult	very difficult

	Common error
a) i)	Where a wrong layer was chosen, 89% chose layer B – Limestone.
ii)	Layer A chosen by 31% of students. Layer C chosen by 26% of students.

	Analysis of responses
d)	A breakdown of the layers chosen to be formed under the sea. Layer A – selected in 38% of answers. Layer B – selected in 23.5% of answers. Layer C – selected in 23.5% of answers. Layer D – selected in 15% of answers.