Yeah the boundary between the red Entrada Sandstone and grey/green Curtis Formation limestone in particular is really sharply defined. It makes sense because that boundary is from when the area that used to be a beach / on the edge of the sea was totally unundated by the sea in a geologic instant :) We are loving Utah so far! I actually plan a couple more posts about this trip, I took a ton of photos and also video clips of the drive through the mountains which was also cool.