Today’s outcrop is a little north of yesterday’s baked angular unconformity in the Paradise Valley between Gardiner and Livingston, Montana. It is an outcrop of a vertical basaltic(?) dike intruded into volcaniclastic conglomeratic sediments. The dike stands up in positive relief because of differential weathering.
There are also a number of small plugs of the same rock just to the northeast of the dike that presumably share its origin. Upon closer inspection, the knobs just to the northeast of the dike appear to be more consolidated deposits of the volcaniclastic conglomerates into which the dike is intruded. None of the field guides of the area I have indicate the age of this dike, but I would presume it is geologically young given the apparently unconsolidated nature of the volcaniclastics that surround it. Note also the center pivot irrigation system in the field in the foreground to get a sense of the scale of this dike. Measuring in Google Earth I estimate it to be about 11 meters wide.
Explore this and all of my 2010 Deskcrops and Outcrops in Google Earth!