The last one, the lovers find it hard to determine whether they are asleep or awake.
Answer: They were tilted after they were deposited; they were originally deposited horizontally; the youngest layer was originally deposited as the bottom layer; their relative ages have not changed even though they are tilted.
Geologic tilting is the process by which the Earth's rock layers begin to slant irregularly. This can be caused by vertical or horizontal faults, <em>angular unconformity</em> and disturbances on the Earth's magnetic field.
A geologist cannot know the exact age of a rock layer just from looking at it. The information can only be obtained by other methods, to an approximation. He can, however, know that the youngest layer is the one that was originally at the bottom. He also knows that the relative age of the layers has not changed.
<em>Angular unconformity</em> occurs when a new layer of sedimentary rock is deposited on layers that were already tilted, thus exacerbating it. By looking at the layer carefully, the geologist can find out whether the tilting happened while the sediments were being deposited, or afterwards. He can also know which way they were originally deposited by studying characteristics such as cracks and ripple marks.
The Scottish-born American industrialist and philanthropist Andrew Carnegie (1835-1919) was one of the first "captains of industry." Leader of the American steel industry from 1873 to 1901, he disposed of his great fortune by endowing educational, cultural, scientific, and technological institutions.
