From Wiktionary, the free dictionary
From lith- + -ify.
lithify (third-person singular simple present lithifies, present participle lithifying, simple past and past participle lithified)
- To turn sediment into solid rock
2003, Ann G. Harris et al., Geology of National Parks[1], →ISBN, page 13:Shale is fine-grained rock made of silt or wet mud that has been lithified by compaction and cementation.
lithify on Wikipedia.Wikipedia