I Think I Figured Out The "Caldera" RiddleThe caldera looks to be centered on the town of Cienega de Escobar. Load up Google earth and zoom in/out to see that Cienega de Escobar is situated on an area of flat, likely alluvial fill in the middle of the caldera, good for agriculture. This is the only area in the entire region that looks like a caldera, the flat central area appearing to be about 5-8 km wide. I estimate an overall diameter of about 15 km, including all of the slump areas around its edges, with the resurgent rhyolite domes.
It is well known that calderas are so large that they are difficult to discern with the naked eye. It took me several times on Google Earth to see it myself.
The REX Sandra-Escobar property only occupies the East to ENE quadrant of the caldera, so there might be a lot more prospective property in the area to be staked. I do not fear posting this here, because Cope chose to ammend the boiler-plate language in his PR's to include a reference to the caldera. So I assume he has already finished looking / staking any other available property in the area.
My earlier post on volcanic tuff might really be quite important, if the source of that tuff was the caldera itself, and not one of the resurgent rhyolite domes. This is likely to be the case, as most mineralization in caldera settings apparently comes from pre-collapse rocks.
Enough for one post. Maybe more later.