Big Important Conference Paper

I'm about a page and a half into the big important conference paper and I've already run into my first major snag--I already disagree with the leading expert in the field on a significant detail. Not just a matter of interpretation, but I think he has the facts wrong. Here's the rundown:

The primary source I'm working with is an account book kept by Pierson B. Reading, a one-time employee of John Sutter at New Helvetia. Reading led a party of Indian trappers in the fall/winter of 1845. This trapping party, and the debts they run up with Sutter for trade goods, is the subject of my paper. According to everything I'm reading in the Reading collection, Reading spent 1845 either at New Helvetia while Sutter was off at war in Southern California, or on this trapping expedition based out of "Camp Hanishaw." To the best that I can tell, this seems to be in the Delta, since Sutter describes Reading's position as "below" New Helvetia and he reports hearing that Reading is on the San Joaquin River near the confluence of the Stanislaus River.

Major problem: In Indian Survival on the California Frontier, Al Hurtado cites Reading's account book as evidence that Reading spent 1845 trapping at the headwaters of the Trinity River in the Siskiyou mountains, waaaay up north.

Maybe this is the problem all green horns like myself run into eventually--the expert seems wrong, but how do I know I'm not overlooking some key detail that someone smarter than myself would immediately recognize as evidence that Reading and Co. were in fact on the Trinity?