The topmost geologic layer, the Cohansey Formation, is composed of sand, gravel, and erosion resistant ironstone.
This layer forms a hard capstone along the highest summits, protecting more easily weathered underlying geologic layers such as the Kirkwood Formation.
"Researchers know that certain churches come from certain geologic layers, but when it comes to pinpointing the place, they are at a loss."
The walls of the Tinker's Creek valley expose four geologic layers.
Engineers also need to calculate the highest rate in each combination of geologic layers as the well is drilled.
Mount Toby is also part of such a geologic layer cake.
An aquifer is a geologic layer which can hold water such as sand and gravel, limestone, or sandstone, through which water flows and is stored.
The ridgeline of the mountains forms the edge of the cap rock layer, which is being eroded relatively slowly, protecting underlying geologic layers from being weathered.
The geologic layers beneath Ocean Beach, starting from the top (i.e. the youngest), are:
Over time, the sediment collected and consolidated into new sandstone at the Garden of the Gods, producing a geologic layer known as the Dakota Formation.