- Deposition of volcanic ash, probably fluvially transported, possibly in a lake or floodplain.
- Uplift (or drop in base level), with subsequent erosion of a large channel.
- Deposition of a debris flow/lahar into that channel.
- Erosion of a smaller channel into that deposit.
- Deposition of a smaller lahar into the smaller channel
- (There may have been other lahar desposits, but I'm not seeing any clear-cut evidence for them)
- Deposition of homogenous tafoni-weathered tuff, either as airfall, or as in #1.
- Eruption of basalt, possibly of CRB/SMB affinity, creating rimrock.
Photo unmodified. August 19, 2011.