Mixed methods research conducted across three semesters in introductory college geology classes (n=187, 190, 138) attempted to ascertain whether integrated study of petrified wood could serve as a portal to improved student geobiological understanding of fossilization, geologic time, and evolution. The Petrified Wood Survey[TM] was administered as a preinstructional and postinstructional assessment in control and experimental classes; the experimental class received integrated petrified wood instruction. Paired t tests of differences in students' pre- and postinstructional scores for control and experimental groups revealed significance ([alpha]= 0.05, effect size = 0.79, confidence interval 0.56-1.01). The students with integrative study showed greater knowledge gains about petrified wood's abundance, properties, nature, location, and geologic time. However, understanding of fossilization geochemistry remained problematic for both groups. The Petrified Wood Survey[TM] is appended. (Contains 9 tables and 2 figures.)