[Recently I came across a Hamilton Cross Country watch. From what I have read, it appeared on the scene in 1956. This model used an Illinois watch movement with 17 jewels. The black inner dial rotates as the hours advanced. The letters P M C E and G represent the US time zones, and Greenwich mean time. It was supposed to appeal to travelers going cross country, but it never really caught on. So from what I gather is that it is an uncommon watch, not rare.
The watch that I purchased is currently in rather sad shape, as it is missing the second hand and has no crystal for it. Stupidly, I forgot to take before pictures of the watch, and it is currently in the hands of a local watch repairman. The pictures that will follow are gleaned from the web, so that what I described will make some sense.