The Little Cottonwood stock is a granitic intrusion that extends from the mouth of the canyon almost to Snowbird ski resort. It is Oligocene in age, roughly 30.5 to 29 million years old, composed primarily of granodiorite, quartz monzonite, and granite, with some mafic enclaves. The Little Cottonwood stock is intruded in its northeast corner by another unit called the White Pine intrusion, and other smaller igneous units, collectively about 27-26 million years old, which are the source of the inactive White Pine molybdenum ore deposit in White Pine fork.