Though this was not the
Looking at the cut, though, there are a couple of things that pop out immediately. There are two distinct sets of deposits here. From this perspective, the lower one looks fairly homogenous, with a kind of "badlands" morphology (It's even more distinct in the next cut). The upper one consists of angular, poorly sorted clasts ranging from quite fine to very large. However, despite being poorly sorted, there is a distinct trend for the clasts to get larger from the base of that deposit up to maybe 15-20 feet above that line. This is backwards from most examples of graded bedding, where the individual fragments start coarse and become more fine upwards, and thus is called "reverse grading." It indicates that even though deposition was occurring, the energy of the flow was increasing. It's an excellent indicator of a debris flow, and can often be seen in cuts in modern alluvial fans. This one, being composed of volcanic rock, would properly be called a lahar. Here's a crop to show the reverse graded portion more closely:
Photo unmodified. October 9, 2012. FlashEarth Location.