Well, you should see a clear difference between the right and left sides of the red line. The right side of the outcrop is the Idaho Springs Formation. To the left of the red line is the Fountain Formation. The Idaho Springs Formation is a Precambrian formation consisting of gneiss, schist and granite with slate filling the spaces between the metamorphic and igneous rock. The outcrop of the ISF at Stop 1 is dominantly a black and white quartz diorite.
Numerous folds are present throughout the formation.
The Fountain Formation is a Paleozoic sedimentary formation consisting of mostly arkosic sandstone and conglomerate. Clasts in the FF are immature, cobble to fine sand. The formation is dominated by feldspar with some quartz and muscovite. The sorting is very poor. Numerous scours are present.