A PROPOSED METHOD FOR RECOGNIZING SELECTED PALEOGASTROLITHS USING A SCANNING ELECTRON MICROSCOPE
Proposed paleogastroliths from the skeletal remains of a Seismosaurus were obtained and examined using an SEM. The samples are mostly highly polished stones composed dominantly of chert, impure chert, and quartzite. The stones were observed at magnifications that ranged from 100x to 400x. The Seismosaurus stones exhibited a micropitted texture, with the cherty stones being significantly smoother than the quartzite stones. All of the cherty samples contained sets of parallel to sub-parallel, curved, polish grooves. In places, the sets of polish grooves crosscut one another. Polish grooves were not noted on either the impure chert or quartzite samples. We suggest that the sets of polish grooves formed as a result of muscle manipulation in the stomach; small particles lodged in the muscle acted in much the same manner as a polishing cloth on the stones.
In conclusion, sets of polish grooves were observed on all of the cherty samples and not noted on the impure chert and the quartzite samples. Therefore, we suggest that the presence of sets of polish grooves on cherty stones found within skeletal material is probable evidence for genuine paleogastroliths. Consequently, the recognition of sets of polish grooves on suspected paleogastroliths outside of skeletal remains would also provide supporting evidence for genuine paleogastroliths.