“During the Pleistocene Epoch (two million to 10,000 years ago before present), the Rush Creek glacier slowly ground its way along the Eastern Sierra, creating a crescent-shaped canyon now called the June Lake Loop. The Loop is located off of 395 south of Mono Lake.” (Mammoth Mountain Environment Eastern Sierra History, pg 6)
The Rush Creek Glacier created June, Gull, Silver and Grant Lakes, and left the “Balanced Rock” perched above the road next to the June Lake Fire Station.
The phenomena that placed the rock in this precarious position is called “glacial erratics” where a piece of rock that differs from the size and type of rock native to the area in which it rests. "Erratics" take their name from the Latin word "errere", and are carried by glacial ice, often over distances of hundreds of kilometers. (Wikepedia.org)
This boulder is 18 feet tall and weighs 150 tons. It was carried by the Rush Creek Glacier to its present position. (Wikepedia.org)