Their GIS data is minimally attributed for the most part, their public wells data set did have a more robust attribution scheme. One cool feature I found in the wells data is that they provide a hyper-link for many features to an on-line site record. Found both shapefiles and file geodatabases in the samples I downloaded.
More interestingly, I opened up their Bedrock Geological Map and noticed something odd to me. See the bulls-eye just NW of center? That, even to a non-geologist like me, does not look too geologic.
Turns out it is related to a meteorite impact known as the Manson Crater, once thought to be The Dinosaur Killer until it was determined to be too old.