Along Rock Creek near the Park Police station are some interesting geological features.
The "measles" in this large boulder come from larger rocks originally embedded in sediment. This rock is schist -- if you split it open, you would see the tell-tale layers.
Years and years of stream action create
"potholes" in the rocks in the stream bed. Can
you find them in the photos below? Since the potholes are
above water level, this must mean that the water level has
changed over time.