I thought we could use a thread for general discussion of the structure of the crater again. I am still intrigued by the question "What's on top?".
I see a number of structures that I will just call "hoods" to avoid any implication about how they form. This image shows the top of the slope at Duck Bay. There is a rough line in the slope about half a meter below the crest. Near the center of the image this "contact" or discontinuity seems to rise over a very large rock. Further to the left the contact rises over a smaller rock where it forms a "hood", a thin layer above the rock and molded to it (perhaps) that protrudes slightly in front of the rock as if it were more resistant to erosion.
Notice also in the image above, a thinner layer at the plain's surface of uniform material, appearing fine-textured, perhaps 20 cm thick. I am now pretty convinced that this material is continuous "bedrock" that overlies the breccia immediately below. I do not understand how it formed. I sure wish scientists would take an interest.
Getting back to "hoods", there are two more clear ones in this image of the slope-top south-west of Bottomless Bay. Look near the slope crest just left of center where two adjacent rocks have little caps or "hoods":
Here are perhaps up to a dozen more "hoods" in this image of the top of the cliff at Bottomless Bay. In most of these cases the underlying rock "mold" (?) is missing. These "hoods" and all the others I think I see are within half a meter of the plain's surface:
There are more examples of hoods scattered along the rim. I think that these hoods may be structures that have formed within the breccia as a result of proximity to the plain's surface, long before their exposure in the eroding crater wall. The "half-meter contact" in the Duck Bay image (first above) is at about the maximum depth that would be reached by diurnal warming. I think that these hoods are yet another chemically formed structure like the fracture fills and rinds.
Here is another image of a continuous top rock layer on Victoria's rim:
I am now fairly convinced that most of the top layer that forms the plain's surface in the image above is rock not soil. At the bottom of this top layer where it meets coarser material, in the distance in this image, there seems to be a thin layer of protruding material more resistant than that above or below it. That material, at least, is clearly rock and clearly not breccia, so what the heck is it?