Ted Hall has been following the Lewis and Clark trail for years. His second book on the the Corps of Discovery's route over Lost Trail Pass is the subject of an autograph party at the Ravalli County Museum Thursday evening, March 1.

"Lost Pass 1805" is the result of years of work by Hall and others to determine how the 1805 expedition crossed into the Bitterroot Valley. The trail at the south end of the valley has been in dispute for quite a while. Hall, an engineer and surveyor has been "groundtruthing" that portion of the route, using William Clark's daily notations in the Corps of Discovery journals. The expedition traveled from St. Louis to the Pacific Coast and back again, leaving only a few physical traces of where they had been, but chronicling their experience.

The Reveal and Premiere Autograph Party will be at Hamilton's Ravalli County Museum, starting at 6 p.m. There will be a presentation of the highlights of the book and supporting statements from those who helped Hall.

The book, published by Stoneydale Press of Stevensville, will be available, and is a companion book to Hall's 2003 publication, "The Trail Between the Rivers," which followed the route between the Dillon area and Orofino, Idaho.

Publisher Dale Burke has been a staunch supporter of Hall's efforts and is proud that the Bitterroot National Forest has accepted the trail location with some trail clearing work and signage.