Abstract On this field trip, participants will get their hands dirty while characterizing soils formed on five different rock types: Archean Gneiss, Flathead Sandstone, Wolsey Shale, Meagher Limestone, and Absaroka Volcanics (a basaltic andesite rock). We first recap prior soil survey efforts across the Gallatin National Forest in southwestern Montana and introduce a state factor approach to understanding soils. For over 50 years, Montana State University faculty have explored parts of this lithosequence, using it as a natural laboratory for thousands of students. We continue this tradition with this field guide, emphasizing how the combination of field and laboratory data can enrich our understanding of soil processes. We will observe and measure striking differences in soils; these differences in physical and chemical properties, from textures and colors to pH and elemental composition, are discussed in the context of quantifying the influence of the underlying rock on soil properties. We use these differences to ask whether heterogeneity in soil properties justifies the inference that soil properties are dominated by the underlying lithology. We conclude that the underlying rock strongly influences soil properties, but in variable ways across this lithosequence. This influence is both direct and indirect: chemical weathering of the rock leads to compositional changes in overlying soil, but rock weathering also leads to coarse fragments in the soil profile, which alters soil hydrology.