Alan, I've not got this one figured out either. The lower, arcuate part looks like a failure surface along impact-induced fractures. Above that it looks jumbled like ejecta. Then above that is a well-defined horizontal layer, with sand above that. Very complex.

--Bill

I agree; this is some complex stratigraphy. Alan has picked the lower boundary of what might be called a 'megabreccia'. And certainly there is a fine-grained lighter colored layer at the very top. It looks as if there is another layer of jumbled rocks between these two. In a couple of places the layer appears to have draped over the boulders of the 'megabreccia'.
The layer immediatly below alan's yellow line is also highly fractured. But the fragments here are more similar in size than the jumble of boulders and debris in the 'megabreccia' above the yellow line.
I'd be very reluctant to try to make any correlations with Endurance at this point.
That's my take anyway.
This is going to take some time and more images to figure out.

Perhaps the layer just below the fine surface coating is lava flows that 'draped' over the Megabreccia, then got soaked in water. The thin top layer is probably what has been quietly accumulating since things quieted down on the planet.