Answer:
Here's what I think
Explanation:
They wanted you to understand that, to a geologist, the stripes on the rock are like the pages of an encyclopedia of information.
You start reading and getting information from page 1 of an encyclopedia, then go on to the next page, and so on.
In the same way, the lowest layer of stripes is the oldest and gives information on the earliest geological period. The layer above it gives you information on the next period, and so on.
