[Ray76]

Gray rock on upper right. This was not subjected to hammering yet it eroded quickly.

on the ground in that area

[EarthResearcher333]

Hi Ray76, Again, in your pictures, it reveals a notable eroded volume of highly fractured weathered rock all along sections of the emergency spillway. This "tumbling rock", carried by the focused 12,000 cfs spillway overflow, led to a convergence in a known historical erosion basin - distinct by the topology. You noted this historical topological inferred erosion "stream" flow in your post & pictures in post 2,554. DWR geologists, in update videos, describe the "seams" of weathered rock that were eroded away, but left the hard & "fresh" remaining blue grey amphibolite which resisted the erosive "weathered rock debris filled flow".

Your second picture only reinforces the evidence of a sharp "V seam" of weathered rock being removed revealing the hard amphibolite base. This would be normal for historic waterflows at these locations causing the weathering & thus becoming the "highly fractured weathered rock".

Keep in mind, that all of the observed eroded weathered rock is gone. Where did it go? It tumbled down the flow channel.

But don't take my word on all of this... look at the DWR geology video of the new mini-fault "seam" discovered at the bottom of the emergency spillway flow. The geologist explains how this seam was revealed by the erosion & the amphibolite that remained.