Patch of tufo and basalt paving covered by wall 4040 on W, ending at line of wall 4025 on N (though does not see to abut this wall ) and either abutting wall 4061 on SE or cut by construction cut 4049 for wall 4061. Another wall on E separates 4041 from basalt paving 4048, a possible doorway through the unnumbered E wall may connect the two. Cut on NE and SE by known actions. Large block in SW corner has rectangular notches cut on 2 S sides-- may be a doorway to/from the paved area. Paving seems to represent a room (interior or exterior), but function unknown.