"Soil horizon" means a distinct layer of soil running parallel to the soil surface, designated as the O, A, B or C horizon proceeding vertically through the soil profile from the soil surface downward.
N.H. Admin. Code § Env-Wq 1002.67
(See Revision Note at chapter heading for Env-Wq 1000) #9086, eff 2-9-08; renumbered by #9904-A (from Env-Wq 1002.66)