As a result, rocks that are otherwise similar, but are now separated by a valley or other erosional feature, can be assumed to be originally continuous.
Layers of sediment do not extend indefinitely; rather, the limits can be recognized and are controlled by the amount and type of sediment available and the size and shape of the sedimentary basin.
As long as sediment is transported to an area, it will eventually be deposited.
The lateral variation in sediment within a stratum is known as sedimentary facies.
In those cases, the lateral limits of the sedimentary layer will be marked by an abrupt change in rock type.
Schematic representation of the principle of lateral continuity.
[
1
]