Page "Stratum" Paragraph 4
from
Wikipedia
Each layer is generally one of a number of parallel layers that lie one upon another, laid down by natural forces.
Strata are typically seen as bands of different colored or differently structured material exposed in cliffs, road cuts, quarries, and river banks.
Each band represents a specific mode of deposition: river silt, beach sand, coal swamp, sand dune, lava bed, etc.
Page 1 of 1.
1.997 seconds.