We took out the long skinny stone (92x27x19cm) in the north of locus 10. So far the the matrix in the southern side is soft yellow-brown w/ some clay & gravel inclusions of a blue-green stone. Under the large stones that we took out the matrix is a hard friable dark bown. There is also a greenish matrix in the SE corner and a round pocket of the grey sand. lrg. capstone length = 170cm. Worked on breaking the lrg. tuff? capstone.