 Ne Ch'e Ddhawa, a cinder cone to the connection of the Yukon and Pelly rivers formed between 0.8 and one million years ago when this area lied beneath the vast Cordilleran Ice Sheet.The youngest volcano, Volcano Mountain just north of the junction of the Yukon and Pelly rivers, formed in past 10,000 years (Holocene), producing lava flows that remain unvegetated and appear to be only a few hundred years old.However, dating of sediments in a lake impounded by the lava flows indicated that the youngest lava flows could not be younger than mid-Holocene and could be early Holocene or older.