The lower park of Gower Gulch cuts into steeply dipping sedimentary layers of the Artist Drive Formation. The Artist Drive Formation consists of a mix of conglomerate, sandstone, marls, mudstone, shale, and volcanic tuff beds deposited in a intermountain basin setting during the middle Tertiary (ranging in age from about 28 to 5 million years ago, spanning the Miocene Epoch into the early Pliocene).