What is the desert rose bit? And the part labeled "???"

I looked up desert rose and it says it is either a flower or a special formation of gypsum/baryite (which looks pretty).

Also I noticed there doesn't appear to be an entrance. And does the fact they are humanoid cats influence the architecture much?

On a side note I would consider trying white text with a black stroke rather than black with white. It might be more readable.