Originally it was a Dry. A combination of both Quill Gordon and March Brown characteristics, tied Wulff style. Supposedly it has enough similar characteristics to pass for both on a mountain stream. The only variation was to be the size. I'll post the particulars of the pattern later.
A google of it will show that Harry Murray has recently, applied the name to many of the different flies he sells. I've seen an article on the "Rapidan" family of flies, etc. An attempt to published more