Steptoe Butte rises above the rolling Palouse of eastern Washington. It is a bit tricky to get a sense of scale. When I first spotted the peak I thought I was seeing Mount Hood, but that would have been an absurd view given how far east I was. The butte rises approximately 1,100 feet above the surrounding rolling hills, but its isolated location makes it stand out as an impressive high point.
The peak is underlain by Precambrian rocks that Waggoner (1984) placed in the Ravalli Group. Due to its isolated exposure the interpretation is a bit tentative.
The butte lends its name to a geologic term. A steptoe is an isolated island of older rock surrounded by younger formations. In this case the billion year plus rocks of Steptoe Butte rise above 15 million year old basalt lava that buried everything else in the area. The butte also rises above vast loess deposits of the wind blown sediment that blew out of the Columbia Basin and settled as a thick blanket of silt over the Palouse creating the rich farmland of the Palouse region of Washington State. Why the butte was not buried in a layer of thick loess is a question that adds to the curiosity of this isolated peak.
The grass and wheat covered ground in the image above is for the most part underlain by the Palouse silts and as such are rich active farmland. The dark band of forest in the low area in the mid distance between the viewer and Steptoe Butte is the Rock Creek drainage. Here the palouse silts were scoured out by ice age floods leaving the area not very viable for wheat growing and instead it is a mix of grazing and pine forest.
Steptoe Butte was named for Colonel Steptoe. However, the butte should not be confused with the hill where Steptoe and his men fought off an Indian attack before escaping near the town of Rosalia.