 Raynolds 's 1848 expedition to the summit of Pico de Orizaba in Mexico predated what is known as the Golden age of alpinism ( 1854 – 65 ) , when many major mountain peaks in the Alps were first climbed . The effort to summit the mountain was one of the earliest deliberate attempts to climb a major mountain peak , and involved logistics , planning and use of rudimentary climbing equipment , " making it one of the more serious mountaineering expeditions undertaken to that point in history . " Though unable to penetrate into the heart of what later became Yellowstone National Park , the Raynolds Expedition produced maps that were used by subsequent explorers to the greater Yellowstone region . Raynolds also located suitable wagon routes in the Bighorn Basin and was able to help narrow down the most appropriate routes for a future transcontinental railroad . The Raynolds Expedition further determined that few if any rivers in the region would be suitable for steamboats due to numerous rapids and steep gradients . Several lighthouses whose construction was designed or supervised by Raynolds are still in use and several are listed on the National Register of Historic Places . 
