>> Gossamer Gear...Trail Days...
Poached from Gossamer Gear's website:
"May 19-21, 2006:Trail Days - Damascus, Virginia
Grant will be exhibiting and selling the latest in Ultralight Gear from Gossamer Gear as well as old favorites. See the new Mariposa Plus, which features the original Mariposa constructed with 2.2 oz. ripstop nylon. Also see the new Squall Classic, a 25 oz. fully enclosed 2 person shelter based on the original Squall Tarptent design from Henry Shires."
As it's a GG product, I agree with Dondo, Jeremy, and David that it's probably made out of Spinnaker Cloth.