The Big Cone Fir in the center of the photo marks the trace of the hinge surface of the Oat Mountain Syncline. The photo is looking west from the East Canyon Motorway. The light colored, resistant beds in most of the photo belong to the lower Pliocene Towsley Formation. Rocks on the far edges of the photo belong to the upper Miocene Sisquoc Formation that contains deep-water, siliceous diatoms that were deposited in a basin plain environment. Where would you suggest that the contact between the two formations might be?