Linear spread of tufo rubble in silty soil mixed with some tile, pottery, and bone located just E of road and S of section of E retaining wall for road 4023. Originally thought to be collapse of part of road retaining wall, but wall seems to have been robbed out here or is at a lower elevation. Layer is most likely a continuation of (=) 4022. the layer composed of the collapse of wall 4007 other tufo and basalt rubble, and various other debris. Underneath layer was another spread of stones that may be part of the retaining wall or more of 4022--to be determined in 2012 when excavation of 4022 is completed.