Doodles of a Pleistocene Yellowstone, Volume III, is a further collection of quick drawings done as simple compositional studies for the Mudpie Project, a visual representation of the 2 million year span of the Pleistocene in Yellowstone, a time of repeated volcanism and glaciation. These 127 drawings depict something of this ancient history—often from the perspective of wandering about on foot—based on impressions from hikes, my own film and digital photographs and drawings in the field—informed by books on glaciation, the park’s geology and a few USGS publications.