Old English Iron Blue Dun

From Trey Combs, Steelhead Fly Fishing and Flies (Frank Amato, 1976):

Tail: Golden pheasant red breast feather fibers
Body: Blue-gray dubbing (muskrat) ribbed with oval silver tinsel
Hackle: Natural black or dark gray
Wing: Gray goose or gray squirrel tail

This was Peter Schwab's favorite steelhead pattern. he called it, "the most universally successful fly I have ever seen." For Schwab it was best a clear water summer-run dressing, and he fished it at the exclusion of many patterns he had designed and made nationally famous. (p.95)

note: my example in the photo uses natural gray sheep's wool rather than muskrat.