i don't think the arena was quarried, just a shallow tunnel dug in then blasted out - the rock there is by and large horrible choss and worthy of its historic neglect
hopefully someday our paths cross there bird-boi - beacon needs more goofy fucks! if'n you haven't done it yet, here's something to do by the drinking fountain on the n side - havne't had any 2nd opinions yet and of course this time of year my sad, sad ego needs intense stroking