Just looks like a geological formation to me.
That picture is from John Wesley Powell’s second expedition to survey the Colorado River between 1871-1872 and taken in April of 1872. It’s generally attributed to James Fennemore, but Elias Olcott Beaman was also one of the photographers. John Karl Hillers had originally been a boatman for the expedition, later acting as a photographic assistant, and the tiny figure sitting on a ledge to the right is said to be him.
If there had been a statue or any kind of remarkable feature, it would surely have been mentioned in Powell’s 1875 “Report on the Exploration of the Colorado River of the West and Its Tributaries” (revised and reissued in 1895 as “The Exploration of the Colorado River and Its Canyons”).