Laurie is correct about the unakite of course.  However the red parts of the dull green and red rocks I referred to are not feldspar. The dull red appears to be some meta-volcanic rock that is as tough as the epidotized meta-volcanic material, and is abundant in the Rose River compared to the less common unakite.

I saw some amazing saprolite prospecting a friend's farm in Charlotte County several weeks ago. The area outcrops were schist, I think partly on its way to gneiss due to distinct banding. I was looking for pegmatite sign, of which a little was seen in one plowed spot, and investigating what the landowner guessed was "black lava" but was really a layer of conglomerated black nodules (likely iron or magnesium ore as found in general region) and quartz fragments.  He had cut a drainage trench and had to break through the hard layer of nodules about 18" below surface. The layer overlaid red clay and quartz in some areas. But elsewhere it overlaid what looked exactly like the schist outcrops -- until you took a trowel or shovel to it!  It cut like butter but retained all the coloring and layering of the schist outcrops. Cool.

I'm  sure I'm over-generalizing what he said, and I certainly don't remember exactly what he spoke back in 1977.  He likely said something like, rotten rock is among places  to find minerals,  and a good sign that you might find something interesting.  But what stuck with me was his glee in describing the hunt.