George Bird Grinnell 
Jack in the Rockies [EPUB ebook] 

At the time Jack Danvers journeyed through the Yellowstone National Park, that wonderful country was little known. Since then it has become famous, and people from all parts of the globe go to visit it. There is no more delightful summer excursion possible than a trip to the National Park where—if one can take a pack train and journey away from the beaten roads and trails—it is still possible to see elk and deer and many other wild animals, almost in their old time abundance.