Tis a shame you put your greasy little fingers on anything that old. Tsk, tsk, white gloves are de rigeur at any archives, if they even let get far enough to pick up an original.
Just having fun..
But, back O/T, for any Ross materials, and over a span of time, you might call Audrey Moriarity at Tufts Archives, 910.295.3642. Tufts has quite a few original documents. Some of Ross' field sketches are on a fine vellum type paper. Audrey can tell what type paper was really used for his field sketches and course plans.
Now, you might also IM Wayne Morrison as I think he got Philly cheesesteak on the Colt Pine Valley plan. The plan absorbed less grease than a napkin if that helps but he can explain.