Quarry is on the contact between a fossiliferous arkose sandstone and a greenschist. These contacts are dolomitized. There was a spring in the quarry that contained hydrogen sulfide. Hot spring alteration aureole. (Dr. Hidemichi Hori, original discoverer of the ammonioleucite-bearing outcrop, went back for a second visit 15 years later and found that the entire occurrence had been carted away by mineral collectors and not a trace of the stuff can now be found.)
Ref.: American Mineralogist (1986): 71, 1022-1027.
