mortar stone foundation wall

huangyhg

mortar & stone foundation wall
i am looking at an existing foundation wall for a home.  the house is estimated at 100+ years old.  the foundation walls for the basement are stone and mortar (probably sandstone).  finished basement floor to top of wall is 6'-8".  the wall is 12" thick (minimum).  the wall looks to be held at the top by the first floor construction.  the basement slab is poured concrete.  the house is located in the midwest (ks/ne border).  i am assuming a soil lateral load of 65 psf/ft.
am i correct in assuming that friction/gravity is resisting shear?  and the mortar on the inside face is in tension resisting bending forces?  where can i find allowable tension for mortar and friction values?
sperling -
there was a recent thread about tensile strength for unreinforced masonry, try a search.   65 pcf sounds somewhat high-  do you have a water table issue?
regards.
with the axial load on the wall from the weight of the building and the self-weight of the wall, you may not necessarily develop tension on the inside face...just need to check it.