http://www.ebay.com/itm/400944282071
This vintage jacket was made around 1910. It is made of white wool flannel, with a dramatic cutaway, unvented back, single button functional cuffs, mother of pearl buttons and a five button (3 functional) front. The shoulder seams are steeply back-slanted, the jacket is half-lined, and it has two steeply slanted internal breast pockets and an internal ticket pocket. I was told this was originally purchased in Big Timber, Montana, though there are no tags left in the jacket.

Chest (pit to pit): 21″ (doubled = 42″)
Shoulder to shoulder: 15-1/2″
Sleeve (shoulder to cuff): 23-3/4″
Length (Base of collar to hem): 31″