hypabyssally

hyp·a·bys·sal

 (hĭp′ə-bĭs′əl, hī′pə-)
adj. Geology
Solidifying chiefly as a minor intrusion, especially as a dike or sill, before reaching the earth's surface. Used of rocks.

hyp′a·bys′sal·ly adv.

hypabyssally

(ˌhɪpəˈbɪsəlɪ)
adv
(Geological Science) in a hypabyssal manner