The Pony Express basaltic ash is locally a useful stratigraphic marker in Lake Bonneville sediments in west-central Utah. The ash was erupted from a vent in the Sevier Desert basin soon after Lake Bonneville had transgressed high enough to flood into the basin about 24,000 years ago. The ash is found at or near the base of the Bonneville marl below altitudes of 1400m (4600 ft) in part of the Sevier Desert basin and the southernmost part of the Great Salt Lake basin. The chemical composition of the ash is similar to that of other basalts in the Sevier Desert. Possible source vents are in the Pahvant Butte area or a maar near Smelter Knolls.
A backhoe trench in deposits of Pleistocene Lake Bonneville and Holocene wetlands below the mouth of Juke Box Cave, near Wendover, Utah, provides an excellent view of the late Pleistocene and Holocene geologic history of the area.
Color booklet that answers questions about the Great Salt Lake and Lake Bonneville such as when did Lake Bonneville exist and what kinds of animals lived around it, why is the Great Salt Lake salty, what islands are in the lake, and what ...