Mystery rocks and mounds

Today Mom and I once again hiked into Highbanks and into the site. This time we took an aproach from the South, just off the path. We walk along the top of the earthworks and probed as we went. Once we got back towards the northern  portion we probed around the exterior and noticed what may be the secound mound or ring of earthworks that Baby mentions in his notes. This was very exciting and we probed along this formation. Strang rocks that seemed really out of place were all along the earthworks ontop of them and around them. Now these rocks seem local but could not have eroded out of the earthworks unless there are sections of the earthworks which contain large stones, perhaps for support. This was really wierd to say the least. Further investigation may come in the future.
We walked back into the enclosure and probed a low area which  we flagged for excavation. In our probes we collected the typical yellow clay and saw red clay and charcoal inclusions. It was exciting because this red clay is only seen inside the earthwork walls and is not local to the area. Further inside the enclosure, as we were working our way South, we saw another wierd occurance. Multiple, small mounds dotted the landscape. It was really odd, they almost looked like sifting piles from Baby's excavation but they were too far away from the earthworks. They also looked like a serial killer had come in and buried a half dozen bodies. Mom probed one, which was braver then me. They turned out to be pretty much solid yellow clay. The mystery increases!!! As we continued to walk back to the path we realized that these mounds were most likely the result of a fallen tree. We saw other trees that had fallen and when the root bulb comes up it brings with it a great deal of clay that is caught in the roots. Once the organics decay it leaves behind the big pile of clay. So no serieal killer mass burial ground, just a bunch of fallen trees....or are they?