Now I know "breech clouts" are a darn handy item to wear around water and in hot weather, but I've never seen historical journals or diaries refer to them as characteristicaly worn by the mountaineers.
off the top of my head come the many diaries of corps of discovery .
Many ,many depictions and information in them
i believe also the writings and descriptions of the Hennery expedition as well as Ashley’s accounts depict legging and breach clout even among the brigades. If you were a free trapper I would think depending on how long you had been out you would also have soon become accustom to wearing a breech cloth or clout when away from civilazation
Captchee,.... Maybe so, but what I've read in "The Journals of Lewis and Clark" by Bernard DeVoto, fails to make any mention of the expedition members wearing "breech cloths",..... I realize this book is a condensed version of the original journals (and lacks sketchs and etc.) so "breech cloths" may very well have been left out as not being important enough to mention.
Also,... I've read "William H. Ashley 1825 Rocky Mountain Papers" several times over the years and failed to notice any mention of "breech cloths" being worn by members of his brigade.
I have no writings with regards to Henry's Expedition, so I don't know if there is any mention of them or not.
Potts, Beall, Drugeon, Ferris, Thomas, Bradbury, Larpenteur, Spalding, Luttig, Russell, Pattie, Ruxton, and Sage,..... also
fail to mention trappers wearing breech cloths, unless I've missed it somewhere. (
which is entirely possible)
Would you care to share some "quotes" from the resources you have,.... I would appreciate any such information/documentation.

(thanks in advance)