Lin, I think those two pictures you posted do show a Spicebush Swallowtail. This site shows more:
http://www.discoverlife.org/mp...
Are there any host plants around there?
I grow Spicebush plants just for those butterflies. A nursery guy once showed me some Spicebush plants, then he showed me the caterpillars. Clever, wasn't he? Well...he sold me a Spicebush plant and I left with one caterpillar also!