From Wikipedia:

"Thanatology is the academic, and often scientific, study of death among human beings."

and

"Lithology once was approximately synonymous with petrography, but in current usage, lithology is a subdivision of petrology focusing on macroscopic hand-sample or outcrop-scale description of rocks, while petrography is the speciality that deals with microscopic details."

I believe the "lithologist" is the study of rocks.

Makes sense to me, but working in word carving and symbolism somehow would as well. "Thanatopictographologist"?