An adventurer and explorer of no mean repute, Lieutenant Frederick Schwatka leads an expedition by mule train into the forbidding Sierra Madre mountains of Mexico to one of the richest silver mining regions in the world. He offers lively (and occasionally disparaging) descriptions of the the unfamiliar flora and fauna of this often desolate region, of the cliff and cave dwellings inhabited and abandoned, and of the social customs of the various peoples he meets. He marvels at the unmatched running prowess of the Rarámuri (Tarahumari) Indians of the Barranca del Cobre--the famous Copper Canyon of Chihuahua State. He writes always with humor that keeps the narrative light and the reader smiling.