The fact that two landmasses are converging creates a downward warp to the west in the interior of North America. This is known as a foreland basin . As a result of this basin being formed, deopisition occurs within it. The closer to the collision, the more muds and coarser-grained particles that are being shed from the east, producing shales, siltstones and sandstones. The further away from the collision, the more limestone is produced.
Mountains form and are eroded.
Quiet, shallow seas, ideal for the deposition of limestones and dolostones. By matching the number in the upper left-hand corner of every photo with this sitemap, this will allow you to see where each photograph was taken.