This map was drawn by, or with the assistance of, an unidentified Clatsop Indian early in January of 1806. If we only had some record of the conversation that was carried on between Clark and his informant, we might be able to make sense of it, but it bears no resemblance to any other map from that time to this. Nevertheless, it is another piece of the material evidence of many Indians' willingness to help the visiting Americans.
Clark has written the phonetic equivalents of the names of the Indian tribes as he heard them. Few are of any significance today, nor for the overall story of the expedition's visit to the lower Columbia River. The only names that were used elsewhere in the extant journals are "Clott Sop" (Clatsop), "Cal-le-moX" (Tillamook) and "Nat-ti."