[362]There is a reasonable view that holds this lake to be the only real feature upon this section of the map and identifies it as Brooks Lake, but Colter never saw or knew of the main branch of the Bighorn River or its source in Brooks Lake. [363]Clark named this mythical lake for William Eustis, who had been representative to Congress from Massachusetts. About this time he was Secretary of War in President Madison’s cabinet. Whatever Colter drew was certainly lacking Lake Eustis, Lake Biddle, and the Rio Grande, Arkansas, and Platte rivers. He was a simple frontiersman who had probably never heard of Eustis or Biddle and was not interested in mapping anything beyond his own route. Had Lewis linked Eustis and Biddle-Riddle lakes together, a possible approximation to Colter’s draft might have appeared. [364]In 1941, Paul J. Shamp, a US. forester, reported the discovery of numerous petrifications in the vicinity of Pass and Scatter creeks in the Thorofare country. This is the line of Colter’s reconstructed route. It has been the author’s desire to make a search for this missing link of evidence by actually going over the route. In 1947, he made a partial exploration during a three day hike. It was enough to suggest the size of the problem. [365]Colter may have reached Chicken Ridge by Fishhawk, Mountain, or Lynx creeks or via Falcon, Mink, or Crooked streams. It must be remembered that this map sheet has been much mussed up. It is impossible to know what has been erased; yet, enough of Colter’s map remains to provide a logical basis for the above itinerary. It is relatively unimportant which creeks he negotiated to reach Chicken Ridge. The vitally important fact is that he drew a sketch of South Arm from that angle which added to the Thumb makes an accurate map of what a trapper would have seen of Yellowstone Lake. [366]J. Neilson Barry has made the most intensive study of the Map of 1814. It is his opinion that Colter drew other map sheets besides the one of the Buffalo Bill country. He also has hope that these sheets may be discovered among the Lewis-Clark-Biddle papers. INDEX