Complex sentence: Josiah Whitney, the first director of the California Geological Survey, lamented that Yosemite Valley may become like what Niagara Falls was at the time a tourist trap where proprietary interests place tolls on every bridge, path, trail, and viewpoint.
Split into simpler sentences: Josiah Whitney, the first director of the California Geological Survey, lamented that Yosemite Valley would meet the same fate as Niagara Falls. At that time, Niagara Falls was a tourist trap that had tolls on every bridge, path, trail, and viewpoint.